Frühere Termine

Reconstructing Words from Right-Bounded Binary Block Words

19.06.2020

A reconstruction problem of words from scattered factors asks for the minimal information, like multisets of scattered factors of a given length or the number of occurrences of scattered factors from a given set, necessary to uniquely determine a word. We show that a word $w\in\{a,b\}^*$ can be reconstructed from the number of occurrences of at most $\min(|w|_a,|w|_b)+1$ scattered factors of the form $a^i b$, where $|w|_a$ is the number of occurrences of the letter $a$ in $w$. Moreover, we generalize the result to alphabets of the form $\{1, \ldots, q\}$ by showing that at most $\sum_{i=1}^{q-1} |w|_i \, (q-i+1)$ scattered factors suffices to reconstruct $w$. Both results improve on the upper bounds known so far. Complexity time bounds on reconstruction algorithms are also considered here.

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Nano Self-assembly and Electrical Function

08.06.2020 von 16:00 bis 17:00

Aquarium-D-036

Self-assembled structures are of large importance in chemistry and biology. Their construction principles may become significant for the future bottom-up construction of three-dimensional electronic architectures. I will review our recent investigations on the electronic charge transport in various nanoscale self-assembled structures, ranging from molecular mono- and bilayers on solid surfaces to regular arrays of metallic nanocubes, formed by directed self-assembly.

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From Monolithic to Cloud-Native

24.04.2020 von 14:00 bis 15:00

Cloud-Native technologies, and especially microservices are enjoying increasing popularity and diffusion in industrial environments, being adopted by several big players such as Amazon, LinkedIn, Netflix, and SoundCloud. Several patterns and platforms such as nginx (www.nginx.org) and Kubernetes (kubernetes.io) exist on the market. During the migration process, practitioners often face common problems, which are due mainly to their lack of knowledge regarding bad practices and patterns. In this session, we provide an introduction of microservices and serverless, reporting their issues and motivations, and describing the most common issues that companies usually postpone accumulating technical debt.

Short Bio: Davide Taibi is Associate Professor at the Tampere University (Finland) where he heads the Cloud and Web Engineering Group (CLoWeE). His research is mainly focused on Empirical Software Engineering applied to cloud-native systems, with a special focus on the migration from monolithic to cloud-native applications. He is investigating processes, and techniques for developing Cloud Native applications, identifying cloud-native specific patterns and anti-patterns. He is member of the International Software Engineering Network  (ISERN) from 2018. Before moving to Finland, he has been Assistant Professor at the Free University of Bozen/Bolzano (2015-2017), post-doctoral research fellow at the Technical University of Kaiserslautern and Fraunhofer Institute for Experimental Software Engineering - IESE (2013-2014) and research fellow at the University of Insubria (2007-2011).
 

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Nano Self-assembly and Electrical Function

10.02.2020 von 16:00 bis 17:00

Aquarium-D-036

Self-assembled structures are of large importance in chemistry and biology. Their construction principles may become significant for the future bottom-up construction of three-dimensional electronic architectures. I will review our recent investigations on the electronic charge transport in various nanoscale self-assembled structures, ranging from molecular mono- and bilayers on solid surfaces to regular arrays of metallic nanocubes, formed by directed self-assembly.

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Nano Self-assembly and Electrical Function

10.02.2020 von 16:00 bis 17:00

Aquarium-D-036

Self-assembled structures are of large importance in chemistry and biology. Their construction principles may become significant for the future bottom-up construction of three-dimensional electronic architectures. I will review our recent investigations on the electronic charge transport in various nanoscale self-assembled structures, ranging from molecular mono- and bilayers on solid surfaces to regular arrays of metallic nanocubes, formed by directed self-assembly.

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MIMO - Wireless Communications meets Radar

MIMO - Wireless Communications meets Radar

Intelligente Systeme - Vom autonomen maschinellen Lernen zur technischen Anwendung

31.01.2020 von 14:00 bis 16:00

Audimax, Hörsaal A

Immer öfter übernehmen intelligente Systeme Aufgaben aus dem täglichen Leben und der Arbeitswelt autonom und zuverlässig.  Tätigkeiten laufen automatisiert im Hintergrund ab und schaffen damit Freiräume für den Nutzer.


Neben der Entlastung des Menschen von einfachen Aufgaben besteht ein weiterer Vorteil darin, dass intelligente Systeme lernfähig sind. Die zunehmende Nutzung dieser Systeme führt zu robusteren, effizienteren und flexibleren Lösungen, da sie sich kontinuierlich selbst verbessern und kontext-abhängig agieren.


Beispielsweise kann eine Kaffeemaschine ihren Nutzer erkennen und die bevorzugte Zubereitungsform wählen, eine Zahnbürste informiert, wenn der Zahlbelag noch nicht vollständig entfernt wurde und eine Ampelanlage schaltet auf die jeweilige Verkehrssituation um.


Intelligente Systeme basieren auf Mechanismen zur kontinuierlichen Überwachung und Anpassung an sich verändernde Parameter. Wesentlich ist dabei die Herausforderung, auf unbekannte Situationen adäquat zu reagieren oder auch bei stark gestörten Bedingungen einsetzbar zu bleiben: Herausforderungen, für die bislang Menschen ihre Kreativität einsetzen. Deswegen besteht das Ziel bei der Entwicklung intelligenter System vorrangig darin, Verfahren und Algorithmen zu entwickeln, die menschliche Kreativität nachbilden können.  


In meinem Vortrag werde ich in das Gebiet intelligente Systeme einführen, einen Überblick über die Arbeit meiner Gruppe geben sowie einen Ausblick auf Herausforderungen und künftige Entwicklungen dieses Forschungsbereiches geben. 

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Intelligente Systeme - Vom autonomen maschinellen Lernen zur technischen Anwendung

31.01.2020 von 14:00 bis 16:00

Audimax, Hörsaal A

Immer öfter übernehmen intelligente Systeme Aufgaben aus dem täglichen Leben und der Arbeitswelt autonom und zuverlässig.  Tätigkeiten laufen automatisiert im Hintergrund ab und schaffen damit Freiräume für den Nutzer.


Neben der Entlastung des Menschen von einfachen Aufgaben besteht ein weiterer Vorteil darin, dass intelligente Systeme lernfähig sind. Die zunehmende Nutzung dieser Systeme führt zu robusteren, effizienteren und flexibleren Lösungen, da sie sich kontinuierlich selbst verbessern und kontext-abhängig agieren.


Beispielsweise kann eine Kaffeemaschine ihren Nutzer erkennen und die bevorzugte Zubereitungsform wählen, eine Zahnbürste informiert, wenn der Zahlbelag noch nicht vollständig entfernt wurde und eine Ampelanlage schaltet auf die jeweilige Verkehrssituation um.


Intelligente Systeme basieren auf Mechanismen zur kontinuierlichen Überwachung und Anpassung an sich verändernde Parameter. Wesentlich ist dabei die Herausforderung, auf unbekannte Situationen adäquat zu reagieren oder auch bei stark gestörten Bedingungen einsetzbar zu bleiben: Herausforderungen, für die bislang Menschen ihre Kreativität einsetzen. Deswegen besteht das Ziel bei der Entwicklung intelligenter System vorrangig darin, Verfahren und Algorithmen zu entwickeln, die menschliche Kreativität nachbilden können.  


In meinem Vortrag werde ich in das Gebiet intelligente Systeme einführen, einen Überblick über die Arbeit meiner Gruppe geben sowie einen Ausblick auf Herausforderungen und künftige Entwicklungen dieses Forschungsbereiches geben. 

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Mit Process Mining zu mehr Transparenz bei Datenanalyse

31.01.2020 von 14:00 bis 15:00

Audimax, Hörsaal A

Händisch erstellte Modelle bilden häufig nicht das vollständige Wissen über einen bestehenden Prozess ab. Prozessteilnehmer kennen oft nur die Arbeitsschritte für die sie selbst verantwortlich sind und können nur unvollständige Informationen über den Gesamtprozess bei der Erstellung des Modells geben. Unvollständige Prozessmodell führen allerdings zu fehlerhaften Prozessausführungen und Prozessanalysen. Mit Hilfe von Process Mining können reale Vorgänge und Prozesse automatisch ermittelt und systematisch analysiert werden.

Nach einer Einführung in Process Mining wird in diesem Vortrag gezeigt, wie Process Mining zu mehr Transparenz bei der Analyse von komplexen Datenstrukturen führen kann. Es werden auch Lösungen für aktuelle Herausforderungen des Process Mining vorgestellt.

 

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Optimale Planung und den Betrieb von effizienten „Net-Zero Energy Factories“

Optimale Planung und den Betrieb von effizienten „Net-Zero Energy Factories“

Extrem kompakten Antriebssysteme für elektrische Fahrzeuge

20.01.2020 von 17:00 bis 18:00

Aquarium-D-036

Fahrzeuge mit elektrischen Antriebsstrang werden zukünftig unseren Straßenverkehr prägen. Die Reichweite und der Preis solcher Fahrzeuge beeinflussen maßgeblich die Nutzerakzeptanz. Die Kosten und die Reichweite werden üblicherweise von der Batteriegröße und dem Fahrzeuggewicht beeinflusst, daher werden für solche Fahrzeuge extrem kompakte elektrische Antriebsstränge mit einem sehr hohen Wirkungsgrad benötig.

Die Fachhochschule Kiel arbeitet im Rahmen verschiedener Forschungsprojekte, u.a. mit Volkswagen, an solchen Antriebssystemen der nächsten bzw. übernächsten Generation. Daraus sind Inverter mit einer Leistungsdichte von mehr als 100kW/l entstanden.

Im Rahmen dieses Vortrages sollen beispielhaft Lösungsansetze für verschiedene Herausforderungen anhand von Forschungsprojekten dargestellt werden.

Zu den Herausforderungen gehören u.a.: das Systemdesgin bei hohen thermischen Anforderungen; die Erhöhung des Wirkungsgrades durch Minimierung der Streu-Induktivitäten im Kommutierungskreis; innovative Ansätze zur Strommessung in Invertern auf möglichst kleinem Bauraum; Treiberentwicklung für einen minimalen Bauraum; Zustandsüberwachung etc.

Im Rahmen des Vortrages sollen die Lösungswegen zu den unterschiedlichen Problemen dargestellt werden, die vielfach aus einem theoretischen Ansatz, einer Schaltungs- oder FEM-Simulation und praktischer Verifizierung bestehen.

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Extrem kompakte Antriebssysteme für elektrische Fahrzeuge

20.01.2020 von 17:00 bis 18:00

Aquarium-D-036

Fahrzeuge mit elektrischen Antriebsstrang werden zukünftig unseren Straßenverkehr prägen. Die Reichweite und der Preis solcher Fahrzeuge beeinflussen maßgeblich die Nutzerakzeptanz. Die Kosten und die Reichweite werden üblicherweise von der Batteriegröße und dem Fahrzeuggewicht beeinflusst, daher werden für solche Fahrzeuge extrem kompakte elektrische Antriebsstränge mit einem sehr hohen Wirkungsgrad benötig.

Die Fachhochschule Kiel arbeitet im Rahmen verschiedener Forschungsprojekte, u.a. mit Volkswagen, an solchen Antriebssystemen der nächsten bzw. übernächsten Generation. Daraus sind Inverter mit einer Leistungsdichte von mehr als 100kW/l entstanden.

Im Rahmen dieses Vortrages sollen beispielhaft Lösungsansetze für verschiedene Herausforderungen anhand von Forschungsprojekten dargestellt werden.

Zu den Herausforderungen gehören u.a.: das Systemdesgin bei hohen thermischen Anforderungen; die Erhöhung des Wirkungsgrades durch Minimierung der Streu-Induktivitäten im Kommutierungskreis; innovative Ansätze zur Strommessung in Invertern auf möglichst kleinem Bauraum; Treiberentwicklung für einen minimalen Bauraum; Zustandsüberwachung etc.

Im Rahmen des Vortrages sollen die Lösungswegen zu den unterschiedlichen Problemen dargestellt werden, die vielfach aus einem theoretischen Ansatz, einer Schaltungs- oder FEM-Simulation und praktischer Verifizierung bestehen.

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Extrem kompakte Antriebssysteme für elektrische Fahrzeuge

20.01.2020 von 17:00 bis 18:00

Aquarium-D-036

Fahrzeuge mit elektrischen Antriebsstrang werden zukünftig unseren Straßenverkehr prägen. Die Reichweite und der Preis solcher Fahrzeuge beeinflussen maßgeblich die Nutzerakzeptanz. Die Kosten und die Reichweite werden üblicherweise von der Batteriegröße und dem Fahrzeuggewicht beeinflusst, daher werden für solche Fahrzeuge extrem kompakte elektrische Antriebsstränge mit einem sehr hohen Wirkungsgrad benötig.

Die Fachhochschule Kiel arbeitet im Rahmen verschiedener Forschungsprojekte, u.a. mit Volkswagen, an solchen Antriebssystemen der nächsten bzw. übernächsten Generation. Daraus sind Inverter mit einer Leistungsdichte von mehr als 100kW/l entstanden.

Im Rahmen dieses Vortrages sollen beispielhaft Lösungsansetze für verschiedene Herausforderungen anhand von Forschungsprojekten dargestellt werden.

Zu den Herausforderungen gehören u.a.: das Systemdesgin bei hohen thermischen Anforderungen; die Erhöhung des Wirkungsgrades durch Minimierung der Streu-Induktivitäten im Kommutierungskreis; innovative Ansätze zur Strommessung in Invertern auf möglichst kleinem Bauraum; Treiberentwicklung für einen minimalen Bauraum; Zustandsüberwachung etc.

Im Rahmen des Vortrages sollen die Lösungswegen zu den unterschiedlichen Problemen dargestellt werden, die vielfach aus einem theoretischen Ansatz, einer Schaltungs- oder FEM-Simulation und praktischer Verifizierung bestehen.

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Innovative soft magnetic materials for electrical drives

20.01.2020 von 16:00 bis 17:00

Aquarium

In electric drive technology and mechatronics the market for variable-speed drives is continuously increasing. These electrical machines are requested to provide maximum drive power whereas only minimum installation space or little weight is required. In addition, there is often the demand for high energy efficiency.
Applications range from electric traction drives for battery electric vehicles, electric aircrafts, fans and compressors to medical technology. The enhancement of mechanical power is usually accomplished by increasing the speed. As a result, the supply frequency of the three-phase system must be significantly elevated compared to drives that work directly on the 50 Hz supply grid. However, this has a strong impact on the power flow within the machine. The increase in the current heat losses in the winding - due to current skin effects at higher frequencies - can be sufficiently counteracted by a suitable winding design. On the contrary, core losses increase intrinsically with the frequency. Hence thinner electrical sheets with reduced losses are used. However this procedure is limited to supply frequencies of 1 kHz due to material composition.
An innovative alternative to standardized electrical sheets is the use of soft magnetic composites (SMC). In addition to a significant reduction of eddy current losses, SMC is a magnetically isotropic material. In contrast to common radial flux machines, the guidance of the magnetic flux can be extended to the third space dimension without additional efforts and costs. As a result, it is possible to develop novel motor designs and manufacturing processes which provide numerous advantages.
During the colloquium talk, current SMC products are presented and compared with conventional soft magnetic materials. In addition, the opportunities and limits of these new materials for electrical drives are demonstrated by means of prototypes and their testing. Finally some indications are given in which scenarios the use of SMC is particularly of advantage.

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Innovative soft magnetic materials for electrical drives

20.01.2020 von 16:00 bis 17:00

Aquarium

In electric drive technology and mechatronics the market for variable-speed drives is continuously increasing. These electrical machines are requested to provide maximum drive power whereas only minimum installation space or little weight is required. In addition, there is often the demand for high energy efficiency.
Applications range from electric traction drives for battery electric vehicles, electric aircrafts, fans and compressors to medical technology. The enhancement of mechanical power is usually accomplished by increasing the speed. As a result, the supply frequency of the three-phase system must be significantly elevated compared to drives that work directly on the 50 Hz supply grid. However, this has a strong impact on the power flow within the machine. The increase in the current heat losses in the winding - due to current skin effects at higher frequencies - can be sufficiently counteracted by a suitable winding design. On the contrary, core losses increase intrinsically with the frequency. Hence thinner electrical sheets with reduced losses are used. However this procedure is limited to supply frequencies of 1 kHz due to material composition.
An innovative alternative to standardized electrical sheets is the use of soft magnetic composites (SMC). In addition to a significant reduction of eddy current losses, SMC is a magnetically isotropic material. In contrast to common radial flux machines, the guidance of the magnetic flux can be extended to the third space dimension without additional efforts and costs. As a result, it is possible to develop novel motor designs and manufacturing processes which provide numerous advantages.
During the colloquium talk, current SMC products are presented and compared with conventional soft magnetic materials. In addition, the opportunities and limits of these new materials for electrical drives are demonstrated by means of prototypes and their testing. Finally some indications are given in which scenarios the use of SMC is particularly of advantage.

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Innovative soft magnetic materials for electrical drives

20.01.2020 von 16:00 bis 17:00

Aquarium

In electric drive technology and mechatronics the market for variable-speed drives is continuously increasing. These electrical machines are requested to provide maximum drive power whereas only minimum installation space or little weight is required. In addition, there is often the demand for high energy efficiency.
Applications range from electric traction drives for battery electric vehicles, electric aircrafts, fans and compressors to medical technology. The enhancement of mechanical power is usually accomplished by increasing the speed. As a result, the supply frequency of the three-phase system must be significantly elevated compared to drives that work directly on the 50 Hz supply grid. However, this has a strong impact on the power flow within the machine. The increase in the current heat losses in the winding - due to current skin effects at higher frequencies - can be sufficiently counteracted by a suitable winding design. On the contrary, core losses increase intrinsically with the frequency. Hence thinner electrical sheets with reduced losses are used. However this procedure is limited to supply frequencies of 1 kHz due to material composition.
An innovative alternative to standardized electrical sheets is the use of soft magnetic composites (SMC). In addition to a significant reduction of eddy current losses, SMC is a magnetically isotropic material. In contrast to common radial flux machines, the guidance of the magnetic flux can be extended to the third space dimension without additional efforts and costs. As a result, it is possible to develop novel motor designs and manufacturing processes which provide numerous advantages.
During the colloquium talk, current SMC products are presented and compared with conventional soft magnetic materials. In addition, the opportunities and limits of these new materials for electrical drives are demonstrated by means of prototypes and their testing. Finally some indications are given in which scenarios the use of SMC is particularly of advantage.

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Absolventenfeier Informatik 2020

Sonderkolloquium Frau Dr. Judith Michael, RWTH Aachen,

The Resurrection of Models: Generative Software Engineering in Research and Real-World Projects

The Resurrection of Models: Generative Software Engineering in Research and Real-World Projects

Magnetic Particle Imaging - Promises and Challenges of an Emerging Imaging Modality

13.01.2020 von 16:00 bis 17:00

Magnetic Particle Imaging (MPI) is a recently invented three-dimensional imaging method that quantitatively measures the spatial distribution of a tracer based on magnetic nanoparticles. The modality promises a high sensitivity and high spatial as well as temporal resolution. There is a high potential of MPI to improve interventional and image-guided surgical procedures because, today, established medical imaging modalities typically excel in only one or two of these important imaging properties. MPI makes use of the non-linear magnetization characteristics of the magnetic nanoparticles.

For this purpose, two magnetic fields are created and superimposed, a static selection field and an oscillatory drive field. If, for instance, SPIONs, i.e. superparamagnetic iron-oxide nanoparticles, are subjected to the oscillatory magnetic field, the particles will react with a non-linear magnetization response, which can be measured with an appropriate pick-up coil arrangement. Due to the non-linearity of the particles' magnetization characteristics, the received signal consists of the fundamental excitation frequency as well as of harmonics, i.e. oscillations with multiples of the fundamental frequency.

After separation of the fundamental signal, the nanoparticle concentration can be estimated based on the harmonics. The spatial coding is realized with the static selection field that produces a field-free point. Essentially, reconstruction in MPI is the solution of an inverse problem, where, based on the measured induction voltages in the pick-up coils, the spatial distribution of the nanoparticles can be estimated. The relation between the measured voltages and the desired tracer distribution is established by the MPI system function.

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Magnetic Particle Imaging - Promises and Challenges of an Emerging Imaging Modality

13.01.2020 von 16:00 bis 17:00

Magnetic Particle Imaging (MPI) is a recently invented three-dimensional imaging method that quantitatively measures the spatial distribution of a tracer based on magnetic nanoparticles. The modality promises a high sensitivity and high spatial as well as temporal resolution. There is a high potential of MPI to improve interventional and image-guided surgical procedures because, today, established medical imaging modalities typically excel in only one or two of these important imaging properties. MPI makes use of the non-linear magnetization characteristics of the magnetic nanoparticles.

For this purpose, two magnetic fields are created and superimposed, a static selection field and an oscillatory drive field. If, for instance, SPIONs, i.e. superparamagnetic iron-oxide nanoparticles, are subjected to the oscillatory magnetic field, the particles will react with a non-linear magnetization response, which can be measured with an appropriate pick-up coil arrangement. Due to the non-linearity of the particles' magnetization characteristics, the received signal consists of the fundamental excitation frequency as well as of harmonics, i.e. oscillations with multiples of the fundamental frequency.

After separation of the fundamental signal, the nanoparticle concentration can be estimated based on the harmonics. The spatial coding is realized with the static selection field that produces a field-free point. Essentially, reconstruction in MPI is the solution of an inverse problem, where, based on the measured induction voltages in the pick-up coils, the spatial distribution of the nanoparticles can be estimated. The relation between the measured voltages and the desired tracer distribution is established by the MPI system function.

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Magnetic Particle Imaging - Promises and Challenges of an Emerging Imaging Modality

13.01.2020 von 16:00 bis 17:00

Magnetic Particle Imaging (MPI) is a recently invented three-dimensional imaging method that quantitatively measures the spatial distribution of a tracer based on magnetic nanoparticles. The modality promises a high sensitivity and high spatial as well as temporal resolution. There is a high potential of MPI to improve interventional and image-guided surgical procedures because, today, established medical imaging modalities typically excel in only one or two of these important imaging properties. MPI makes use of the non-linear magnetization characteristics of the magnetic nanoparticles.

For this purpose, two magnetic fields are created and superimposed, a static selection field and an oscillatory drive field. If, for instance, SPIONs, i.e. superparamagnetic iron-oxide nanoparticles, are subjected to the oscillatory magnetic field, the particles will react with a non-linear magnetization response, which can be measured with an appropriate pick-up coil arrangement. Due to the non-linearity of the particles' magnetization characteristics, the received signal consists of the fundamental excitation frequency as well as of harmonics, i.e. oscillations with multiples of the fundamental frequency.

After separation of the fundamental signal, the nanoparticle concentration can be estimated based on the harmonics. The spatial coding is realized with the static selection field that produces a field-free point. Essentially, reconstruction in MPI is the solution of an inverse problem, where, based on the measured induction voltages in the pick-up coils, the spatial distribution of the nanoparticles can be estimated. The relation between the measured voltages and the desired tracer distribution is established by the MPI system function.

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Magnetic Particle Imaging - Promises and Challenges of an Emerging Imaging Modality

13.01.2020 von 16:00 bis 17:00

Magnetic Particle Imaging (MPI) is a recently invented three-dimensional imaging method that quantitatively measures the spatial distribution of a tracer based on magnetic nanoparticles. The modality promises a high sensitivity and high spatial as well as temporal resolution. There is a high potential of MPI to improve interventional and image-guided surgical procedures because, today, established medical imaging modalities typically excel in only one or two of these important imaging properties. MPI makes use of the non-linear magnetization characteristics of the magnetic nanoparticles.

For this purpose, two magnetic fields are created and superimposed, a static selection field and an oscillatory drive field. If, for instance, SPIONs, i.e. superparamagnetic iron-oxide nanoparticles, are subjected to the oscillatory magnetic field, the particles will react with a non-linear magnetization response, which can be measured with an appropriate pick-up coil arrangement. Due to the non-linearity of the particles' magnetization characteristics, the received signal consists of the fundamental excitation frequency as well as of harmonics, i.e. oscillations with multiples of the fundamental frequency.

After separation of the fundamental signal, the nanoparticle concentration can be estimated based on the harmonics. The spatial coding is realized with the static selection field that produces a field-free point. Essentially, reconstruction in MPI is the solution of an inverse problem, where, based on the measured induction voltages in the pick-up coils, the spatial distribution of the nanoparticles can be estimated. The relation between the measured voltages and the desired tracer distribution is established by the MPI system function.

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Advanced functional materials for sustainable energy applications

16.12.2019 von 16:00 bis 17:00

Aquarium-D-036

Research on phase transitions in advanced functional materials is widespread and continues to grow. Scientific interest aside, they are attractive for a wide range of current and future technologies that include computation, medical instrumentation, and energy conversion and storage. During this talk, I will present my work on ferromagnetic, ferroelectric and ferroelastic phase transitions that permit large thermal changes to be driven by changes in magnetic field, electric field or stress field. The resulting magnetocaloric, electrocaloric and mechanocaloric (barocaloric and elastocaloric) effects promise new cooling technologies that are energy efficient and environmentally friendly. The materials that I study include multiferroic materials that possess strong magnetoelectric coupling, which are interesting also for applications in sensors, actuators and data storage.

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Advanced functional materials for sustainable energy applications

16.12.2019 von 16:00 bis 17:00

Aquarium-D-036

Research on phase transitions in advanced functional materials is widespread and continues to grow. Scientific interest aside, they are attractive for a wide range of current and future technologies that include computation, medical instrumentation, and energy conversion and storage. During this talk, I will present my work on ferromagnetic, ferroelectric and ferroelastic phase transitions that permit large thermal changes to be driven by changes in magnetic field, electric field or stress field. The resulting magnetocaloric, electrocaloric and mechanocaloric (barocaloric and elastocaloric) effects promise new cooling technologies that are energy efficient and environmentally friendly. The materials that I study include multiferroic materials that possess strong magnetoelectric coupling, which are interesting also for applications in sensors, actuators and data storage.

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Advanced functional materials for sustainable energy applications

16.12.2019 von 16:00 bis 17:00

Aquarium-D-036

Research on phase transitions in advanced functional materials is widespread and continues to grow. Scientific interest aside, they are attractive for a wide range of current and future technologies that include computation, medical instrumentation, and energy conversion and storage. During this talk, I will present my work on ferromagnetic, ferroelectric and ferroelastic phase transitions that permit large thermal changes to be driven by changes in magnetic field, electric field or stress field. The resulting magnetocaloric, electrocaloric and mechanocaloric (barocaloric and elastocaloric) effects promise new cooling technologies that are energy efficient and environmentally friendly. The materials that I study include multiferroic materials that possess strong magnetoelectric coupling, which are interesting also for applications in sensors, actuators and data storage.

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On Privacy Notions in Anonymous Communication

On Privacy Notions in Anonymous Communication

On Privacy Notions in Anonymous Communication

Silicon photonics for electronic photonic integration

02.12.2019 von 16:00 bis 17:00

Abstract:

Already since the advent of cable telephony there is a remarkable growth of network traffic on a global scale. A similarity to Moore’s law of microelectronics has been pointed out. In fact, this permanent growth would have been impossible without the fascinating advance of IC technology.  The technologies required to sustain this unprecedented growth are photonic and electronic integration. Optical solutions intimately integrated with electronics are required to satisfy the demand of bandwidth, energy-per-bit, and cost. The power horse of electronic photonic integration is silicon photonics, in particular photonic CMOS or BiCMOS technologies. Going beyond the concept of present More-than-Moore technologies, photonic BiCMOS combines 2 high-performance technology sub-modules (high –performance HBTs and photonics) with a baseline CMOS process. The added complexity pays off with a full set of photonic features fit for broad-band optoelectronic system integration.

The talk shall provide a short introduction to the field of silicon photonics. We shall then present IHP’s perspective on a photonic More-than-Moore technology, joining most advanced HBT technology with high-speed photonic devices in photonic BiCMOS. The final part of the presentation will present examples of photonic electronic integration for a range of applications.

 

Bio:

Lars Zimmermann leads the silicon photonics team at IHP, the Leibniz Institute für innovative Mikroelektronik in Frankfurt (Oder) and is professor at TU Berlin in the field of silicon photonics. He coordinates the cooperation of IHP and TU Berlin in the frame of the Joint Lab Silicon Photonics. His current work is dedicated to high-performance photonic-electronic integration for optical communications and for nonlinear optical signal processing. Lars Zimmermann undertook his postgraduate studies at Katholieke Universiteit Leuven, Belgium. In Leuven, he was affiliated with IMEC where he worked for 5 years and received a PhD degree in 2003. His scientific work at IMEC dealt with the development of extended short-wave infrared detector arrays and sensor assembly processes. In 2004, Lars Zimmermann moved to TU Berlin. In Berlin, he worked for 5 years on silicon-based optical motherboard technology, realizing early hybrid assemblies of silicon waveguides with lasers, semiconductor optical amplifiers, and detectors. In 2008, Lars Zimmermann moved to IHP, directing IHP’s silicon photonics developments. In 2018, he re-joined TU Berlin.

 

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Silicon photonics for electronic photonic integration

02.12.2019 von 16:00 bis 17:00

Abstract:

Already since the advent of cable telephony there is a remarkable growth of network traffic on a global scale. A similarity to Moore’s law of microelectronics has been pointed out. In fact, this permanent growth would have been impossible without the fascinating advance of IC technology.  The technologies required to sustain this unprecedented growth are photonic and electronic integration. Optical solutions intimately integrated with electronics are required to satisfy the demand of bandwidth, energy-per-bit, and cost. The power horse of electronic photonic integration is silicon photonics, in particular photonic CMOS or BiCMOS technologies. Going beyond the concept of present More-than-Moore technologies, photonic BiCMOS combines 2 high-performance technology sub-modules (high –performance HBTs and photonics) with a baseline CMOS process. The added complexity pays off with a full set of photonic features fit for broad-band optoelectronic system integration.

The talk shall provide a short introduction to the field of silicon photonics. We shall then present IHP’s perspective on a photonic More-than-Moore technology, joining most advanced HBT technology with high-speed photonic devices in photonic BiCMOS. The final part of the presentation will present examples of photonic electronic integration for a range of applications.

 

Bio:

Lars Zimmermann leads the silicon photonics team at IHP, the Leibniz Institute für innovative Mikroelektronik in Frankfurt (Oder) and is professor at TU Berlin in the field of silicon photonics. He coordinates the cooperation of IHP and TU Berlin in the frame of the Joint Lab Silicon Photonics. His current work is dedicated to high-performance photonic-electronic integration for optical communications and for nonlinear optical signal processing. Lars Zimmermann undertook his postgraduate studies at Katholieke Universiteit Leuven, Belgium. In Leuven, he was affiliated with IMEC where he worked for 5 years and received a PhD degree in 2003. His scientific work at IMEC dealt with the development of extended short-wave infrared detector arrays and sensor assembly processes. In 2004, Lars Zimmermann moved to TU Berlin. In Berlin, he worked for 5 years on silicon-based optical motherboard technology, realizing early hybrid assemblies of silicon waveguides with lasers, semiconductor optical amplifiers, and detectors. In 2008, Lars Zimmermann moved to IHP, directing IHP’s silicon photonics developments. In 2018, he re-joined TU Berlin.

 

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Silicon photonics for electronic photonic integration

02.12.2019 von 16:00 bis 17:00

Abstract:

Already since the advent of cable telephony there is a remarkable growth of network traffic on a global scale. A similarity to Moore’s law of microelectronics has been pointed out. In fact, this permanent growth would have been impossible without the fascinating advance of IC technology.  The technologies required to sustain this unprecedented growth are photonic and electronic integration. Optical solutions intimately integrated with electronics are required to satisfy the demand of bandwidth, energy-per-bit, and cost. The power horse of electronic photonic integration is silicon photonics, in particular photonic CMOS or BiCMOS technologies. Going beyond the concept of present More-than-Moore technologies, photonic BiCMOS combines 2 high-performance technology sub-modules (high –performance HBTs and photonics) with a baseline CMOS process. The added complexity pays off with a full set of photonic features fit for broad-band optoelectronic system integration.

The talk shall provide a short introduction to the field of silicon photonics. We shall then present IHP’s perspective on a photonic More-than-Moore technology, joining most advanced HBT technology with high-speed photonic devices in photonic BiCMOS. The final part of the presentation will present examples of photonic electronic integration for a range of applications.

 

Bio:

Lars Zimmermann leads the silicon photonics team at IHP, the Leibniz Institute für innovative Mikroelektronik in Frankfurt (Oder) and is professor at TU Berlin in the field of silicon photonics. He coordinates the cooperation of IHP and TU Berlin in the frame of the Joint Lab Silicon Photonics. His current work is dedicated to high-performance photonic-electronic integration for optical communications and for nonlinear optical signal processing. Lars Zimmermann undertook his postgraduate studies at Katholieke Universiteit Leuven, Belgium. In Leuven, he was affiliated with IMEC where he worked for 5 years and received a PhD degree in 2003. His scientific work at IMEC dealt with the development of extended short-wave infrared detector arrays and sensor assembly processes. In 2004, Lars Zimmermann moved to TU Berlin. In Berlin, he worked for 5 years on silicon-based optical motherboard technology, realizing early hybrid assemblies of silicon waveguides with lasers, semiconductor optical amplifiers, and detectors. In 2008, Lars Zimmermann moved to IHP, directing IHP’s silicon photonics developments. In 2018, he re-joined TU Berlin.

 

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Survey of state estimation for (bio)chemical systems - A personal perspective

Survey of state estimation for (bio)chemical systems - A personal perspective

Survey of state estimation for (bio)chemical systems - A personal perspective

Survey of state estimation for (bio)chemical systems - A personal perspective

Control and planning for autonomous systems under uncertainty - fusing predictive control and learning with guarantees

Kolloquium (ET/IT) von Professor Dr.-Ing. Rolf Findeisen, Institute for Automation Engineering (IFAT) Laboratory for Systems Theory and Automatic Control Otto-von-Guericke University Magdeburg

18.11.2019 von 16:00 bis 17:00

Weitere Informationen erhalten Sie hier

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Control and planning for autonomous systems under uncertainty - fusing predictive control and learning with guarantees

Control and planning for autonomous systems under uncertainty - fusing predictive control and learning with guarantees

An Algorithmic Method of Partial Derivatives

15.11.2019 von 14:15 bis 15:00

We give applications of the following problem to parameterized algorithms: Given a d × d matrix A, whose entries are linear forms, and a differential operator T of degree d represented by a (skew) arithmetic circuit, decide if the partial derivative of det(A) by T vanishes. This approach leads to improvements and significant simplifications of previous parameterized algorithms for unweighted problems. This question is connected to recent approaches in parameterized algorithms involving the exterior algebra and Waring rank, and raises natural questions in commutative algebra that could yield further improvements.

This is joint work with Kevin Pratt from CMU.

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An Algorithmic Method of Partial Derivatives

15.11.2019 von 14:15 bis 15:00

We give applications of the following problem to parameterized algorithms: Given a d × d matrix A, whose entries are linear forms, and a differential operator T of degree d represented by a (skew) arithmetic circuit, decide if the partial derivative of det(A) by T vanishes. This approach leads to improvements and significant simplifications of previous parameterized algorithms for unweighted problems. This question is connected to recent approaches in parameterized algorithms involving the exterior algebra and Waring rank, and raises natural questions in commutative algebra that could yield further improvements.

This is joint work with Kevin Pratt from CMU.

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An Algorithmic Method of Partial Derivatives

15.11.2019 von 14:15 bis 15:00

We give applications of the following problem to parameterized algorithms: Given a d × d matrix A, whose entries are linear forms, and a differential operator T of degree d represented by a (skew) arithmetic circuit, decide if the partial derivative of det(A) by T vanishes. This approach leads to improvements and significant simplifications of previous parameterized algorithms for unweighted problems. This question is connected to recent approaches in parameterized algorithms involving the exterior algebra and Waring rank, and raises natural questions in commutative algebra that could yield further improvements.

This is joint work with Kevin Pratt from CMU.

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Dynamic multi-frequency analysis: looking into the dynamic behaviour of electrochemical systems

13.11.2019 von 12:00 bis 13:00

Aquarium

Dynamic multi-frequency analysis (DMFA) is a tool that allows acquiring dynamic impedance spectra of electrochemical systems in a large range of frequencies, from 1 MHz down to few Hz, with high time-resolved precision [1,2]. Starting from the physical definition of impedance and admittance, and using Volterra series, it has been shown how the concept of dynamic impedance is an extension of the concept of stationary impedance [3]. Here an overlook in the application of dynamic multi-frequency analysis to several electrochemical systems will be shown, among which electron transfer to a redox couple, hydrogen evolution reaction, ion intercalation in Prussian blue analogues and lithium manganese oxide, silicon electro-oxidation. In particular, several aspects of modeling and fitting the dynamic impedance spectra will be addressed. In addition to this, a short overview on the analysis of the dynamic non-linear frequency response in electrochemical systems will be addressed, and first experimental results on electron transfer to a redox couple will be shown.

 

Literature:

 

[1] A. Battistel, G. Du and F. La Mantia, Electroanal. 2016, 28, 2346.

[2] D. Koster, G. Du, A. Battistel, and F. La Mantia, Electrochim. Acta 2017, 246, 553

[3] A. Battistel, and F. La Mantia, Electrochim. Acta 2019, 304, 513.

 

 

 

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Dynamic multi-frequency analysis: looking into the dynamic behaviour of electrochemical systems

13.11.2019 von 12:00 bis 13:00

Aquarium

Dynamic multi-frequency analysis (DMFA) is a tool that allows acquiring dynamic impedance spectra of electrochemical systems in a large range of frequencies, from 1 MHz down to few Hz, with high time-resolved precision [1,2]. Starting from the physical definition of impedance and admittance, and using Volterra series, it has been shown how the concept of dynamic impedance is an extension of the concept of stationary impedance [3]. Here an overlook in the application of dynamic multi-frequency analysis to several electrochemical systems will be shown, among which electron transfer to a redox couple, hydrogen evolution reaction, ion intercalation in Prussian blue analogues and lithium manganese oxide, silicon electro-oxidation. In particular, several aspects of modeling and fitting the dynamic impedance spectra will be addressed. In addition to this, a short overview on the analysis of the dynamic non-linear frequency response in electrochemical systems will be addressed, and first experimental results on electron transfer to a redox couple will be shown.

 

Literature:

 

[1] A. Battistel, G. Du and F. La Mantia, Electroanal. 2016, 28, 2346.

[2] D. Koster, G. Du, A. Battistel, and F. La Mantia, Electrochim. Acta 2017, 246, 553

[3] A. Battistel, and F. La Mantia, Electrochim. Acta 2019, 304, 513.

 

 

 

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Dynamic multi-frequency analysis: looking into the dynamic behaviour of electrochemical systems

13.11.2019 von 12:00 bis 13:00

Aquarium

Dynamic multi-frequency analysis (DMFA) is a tool that allows acquiring dynamic impedance spectra of electrochemical systems in a large range of frequencies, from 1 MHz down to few Hz, with high time-resolved precision [1,2]. Starting from the physical definition of impedance and admittance, and using Volterra series, it has been shown how the concept of dynamic impedance is an extension of the concept of stationary impedance [3]. Here an overlook in the application of dynamic multi-frequency analysis to several electrochemical systems will be shown, among which electron transfer to a redox couple, hydrogen evolution reaction, ion intercalation in Prussian blue analogues and lithium manganese oxide, silicon electro-oxidation. In particular, several aspects of modeling and fitting the dynamic impedance spectra will be addressed. In addition to this, a short overview on the analysis of the dynamic non-linear frequency response in electrochemical systems will be addressed, and first experimental results on electron transfer to a redox couple will be shown.

 

Literature:

 

[1] A. Battistel, G. Du and F. La Mantia, Electroanal. 2016, 28, 2346.

[2] D. Koster, G. Du, A. Battistel, and F. La Mantia, Electrochim. Acta 2017, 246, 553

[3] A. Battistel, and F. La Mantia, Electrochim. Acta 2019, 304, 513.

 

 

 

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Label-free particle and cell sorting based on inherent physical properties

11.11.2019 von 16:00 bis 17:00

Cell sorting is a key tool in medicine and biology to find and characterize cells of interest. Whereas standard immune-labelling is a powerful technique combined with for example fluorescence activated cell sorting (FACS), it does require expensive and sensitive equipment and reagents. Instead, we rely on the inherent physical properties of cells to avoid any need for labelling, and by implementing our sorting schemes on microfluidics platforms we make the preparation and analysis of a sample simpler, more widely accessible and cheaper.

In our laboratory we pioneered morphology, density and deformability-based sorting using deterministic lateral displacement (DLD) [1, 2] [3]. We characterized the mechanical and morphological properties of different variants of red blood cells as well as cancer cells and bacteria. We demonstrated the sorting of bacterial chains of different lengths[4], which is relevant due to the dependence of the morphology on virulence. We have been looking into nanoscale particles with our aims focused on extracellular vesicles. By combining the DLD with electrokinetics, we can tune the separation and sort particles that are close to 100nm [5].

Overall, we try to develop novel sorting schemes that rely on the inherent properties of the particles. This way we not only simplify the sorting but also open up for novel sorting parameters that are not accessible using standard approaches.

1.         Beech, J.P., et al., Sorting cells by size, shape and deformability. Lab on a Chip, 2012. 12(6): p. 1048-1051.

2.         Holm, S., J.P. Beech, and J.O. Tegenfeldt. Combined Density and Size-Based Sorting in Deterministic Lateral Displacement Devices. in microTAS2013. 2013.                       Freiburg, Germany: Society for Chemistry and Micro-Nano Systems.

3.        Holm, S.H., et al., Simplifying microfluidic separation devices towards field-detection of blood parasites. Analytical Methods, 2016. 8: p. 3291-3300.

4.         Beech, J.P., et al., Separation of pathogenic bacteria by chain length. Analytica Chimica Acta, 2018. 1000: p. 223-231.

5.         Beech, J.P., et al., Active Posts in Deterministic Lateral Displacement Devices. Advanced Materials Technologies, 2019. 4(9): p. 1900339.

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Kolloquium (Mawi) von Prof. Tegenfeldt, Universität Lund (Schweden)

Label-free particle and cell sorting based on inherent physical properties

11.11.2019 von 16:00 bis 17:00

Cell sorting is a key tool in medicine and biology to find and characterize cells of interest. Whereas standard immune-labelling is a powerful technique combined with for example fluorescence activated cell sorting (FACS), it does require expensive and sensitive equipment and reagents. Instead, we rely on the inherent physical properties of cells to avoid any need for labelling, and by implementing our sorting schemes on microfluidics platforms we make the preparation and analysis of a sample simpler, more widely accessible and cheaper.

In our laboratory we pioneered morphology, density and deformability-based sorting using deterministic lateral displacement (DLD) [1, 2] [3]. We characterized the mechanical and morphological properties of different variants of red blood cells as well as cancer cells and bacteria. We demonstrated the sorting of bacterial chains of different lengths[4], which is relevant due to the dependence of the morphology on virulence. We have been looking into nanoscale particles with our aims focused on extracellular vesicles. By combining the DLD with electrokinetics, we can tune the separation and sort particles that are close to 100nm [5].

Overall, we try to develop novel sorting schemes that rely on the inherent properties of the particles. This way we not only simplify the sorting but also open up for novel sorting parameters that are not accessible using standard approaches.

1.         Beech, J.P., et al., Sorting cells by size, shape and deformability. Lab on a Chip, 2012. 12(6): p. 1048-1051.

2.         Holm, S., J.P. Beech, and J.O. Tegenfeldt. Combined Density and Size-Based Sorting in Deterministic Lateral Displacement Devices. in microTAS2013. 2013.                       Freiburg, Germany: Society for Chemistry and Micro-Nano Systems.

3.        Holm, S.H., et al., Simplifying microfluidic separation devices towards field-detection of blood parasites. Analytical Methods, 2016. 8: p. 3291-3300.

4.         Beech, J.P., et al., Separation of pathogenic bacteria by chain length. Analytica Chimica Acta, 2018. 1000: p. 223-231.

5.         Beech, J.P., et al., Active Posts in Deterministic Lateral Displacement Devices. Advanced Materials Technologies, 2019. 4(9): p. 1900339.

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Label-free particle and cell sorting based on inherent physical properties

11.11.2019 von 16:00 bis 17:00

Cell sorting is a key tool in medicine and biology to find and characterize cells of interest. Whereas standard immune-labelling is a powerful technique combined with for example fluorescence activated cell sorting (FACS), it does require expensive and sensitive equipment and reagents. Instead, we rely on the inherent physical properties of cells to avoid any need for labelling, and by implementing our sorting schemes on microfluidics platforms we make the preparation and analysis of a sample simpler, more widely accessible and cheaper.

In our laboratory we pioneered morphology, density and deformability-based sorting using deterministic lateral displacement (DLD) [1, 2] [3]. We characterized the mechanical and morphological properties of different variants of red blood cells as well as cancer cells and bacteria. We demonstrated the sorting of bacterial chains of different lengths[4], which is relevant due to the dependence of the morphology on virulence. We have been looking into nanoscale particles with our aims focused on extracellular vesicles. By combining the DLD with electrokinetics, we can tune the separation and sort particles that are close to 100nm [5].

Overall, we try to develop novel sorting schemes that rely on the inherent properties of the particles. This way we not only simplify the sorting but also open up for novel sorting parameters that are not accessible using standard approaches.

1.         Beech, J.P., et al., Sorting cells by size, shape and deformability. Lab on a Chip, 2012. 12(6): p. 1048-1051.

2.         Holm, S., J.P. Beech, and J.O. Tegenfeldt. Combined Density and Size-Based Sorting in Deterministic Lateral Displacement Devices. in microTAS2013. 2013.                       Freiburg, Germany: Society for Chemistry and Micro-Nano Systems.

3.        Holm, S.H., et al., Simplifying microfluidic separation devices towards field-detection of blood parasites. Analytical Methods, 2016. 8: p. 3291-3300.

4.         Beech, J.P., et al., Separation of pathogenic bacteria by chain length. Analytica Chimica Acta, 2018. 1000: p. 223-231.

5.         Beech, J.P., et al., Active Posts in Deterministic Lateral Displacement Devices. Advanced Materials Technologies, 2019. 4(9): p. 1900339.

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Unconscious Bias – Unbewusste Vorurteile

06.11.2019 von 16:00 bis 18:00

Jeden Tag treffen wir Entscheidungen und glauben, dass diese sachlich begründet sind. Tatsächlich gilt dies nur für die wenigsten unserer Entscheidungen. Diese sind vielmehr überwiegend ein Produkt unseres Bauchgefühls, basierend auf den Vorgaben unseres Unterbewusstseins. Wenn wir die Kompetenz und Leistung von Menschen bewerten, beurteilen wir niemals nur die Leistung, sondern immer auch den Menschen. Und so kommt es, dass wir die Leistung von Männern und Frauen, von schlanken und dicken Menschen, von Einheimischen und Ausländern ganz unterschiedlich bewerten. In unsere Bewertung fließen jede Menge Aspekte mit hinein, die in der Leistungsbeurteilung nichts zu suchen haben.
Der interaktive Vortrag „Unconscious Bias“ klärt darüber auf, und beschäftigt sich mit folgenden Themen

  • Was sind unbewusste Vorurteile und woher kommen sie?    
  • Welche unbewussten Vorurteile bestehen im Berufsleben?
  • Wie wirken sich diese aus?
  • Was kann man gegen die unbewussten Vorurteile tun?

                                     

Dr. Nicola Byok
        Dr. Nicola Byok           

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Unconscious Bias – Unbewusste Vorurteile

06.11.2019 von 16:00 bis 18:00

Jeden Tag treffen wir Entscheidungen und glauben, dass diese sachlich begründet sind. Tatsächlich gilt dies nur für die wenigsten unserer Entscheidungen. Diese sind vielmehr überwiegend ein Produkt unseres Bauchgefühls, basierend auf den Vorgaben unseres Unterbewusstseins. Wenn wir die Kompetenz und Leistung von Menschen bewerten, beurteilen wir niemals nur die Leistung, sondern immer auch den Menschen. Und so kommt es, dass wir die Leistung von Männern und Frauen, von schlanken und dicken Menschen, von Einheimischen und Ausländern ganz unterschiedlich bewerten. In unsere Bewertung fließen jede Menge Aspekte mit hinein, die in der Leistungsbeurteilung nichts zu suchen haben.
Der interaktive Vortrag „Unconscious Bias“ klärt darüber auf, und beschäftigt sich mit folgenden Themen

  • Was sind unbewusste Vorurteile und woher kommen sie?    
  • Welche unbewussten Vorurteile bestehen im Berufsleben?
  • Wie wirken sich diese aus?
  • Was kann man gegen die unbewussten Vorurteile tun?

                                     

Dr. Nicola Byok
        Dr. Nicola Byok           

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Unconscious Bias – Unbewusste Vorurteile

06.11.2019 von 16:00 bis 18:00

Jeden Tag treffen wir Entscheidungen und glauben, dass diese sachlich begründet sind. Tatsächlich gilt dies nur für die wenigsten unserer Entscheidungen. Diese sind vielmehr überwiegend ein Produkt unseres Bauchgefühls, basierend auf den Vorgaben unseres Unterbewusstseins. Wenn wir die Kompetenz und Leistung von Menschen bewerten, beurteilen wir niemals nur die Leistung, sondern immer auch den Menschen. Und so kommt es, dass wir die Leistung von Männern und Frauen, von schlanken und dicken Menschen, von Einheimischen und Ausländern ganz unterschiedlich bewerten. In unsere Bewertung fließen jede Menge Aspekte mit hinein, die in der Leistungsbeurteilung nichts zu suchen haben.
Der interaktive Vortrag „Unconscious Bias“ klärt darüber auf, und beschäftigt sich mit folgenden Themen

  • Was sind unbewusste Vorurteile und woher kommen sie?    
  • Welche unbewussten Vorurteile bestehen im Berufsleben?
  • Wie wirken sich diese aus?
  • Was kann man gegen die unbewussten Vorurteile tun?

                                     

Dr. Nicola Byok
        Dr. Nicola Byok           

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Ferroelectricity in methylammonium lead iodide perovskite solar cells

21.10.2019 von 16:00 bis 17:00

Among the emerging photovoltaic technologies, perovskite solar cells stand out with remarkable power conversion efficiencies (PCEs) and low-cost solution processability, rivaling established technologies. Currently, the scientific community controversially discusses the importance of the ferroic properties for the exceptional performance of MAPbI3 light-harvesting layers.

 

In this work, we performed a comprehensive AFM study including Piezoresponse Force Microscopy (PFM) and Kelvin Probe Force Microscopy (KPFM). On large flat crystals, we find 90 nm wide ferroelectric domains of alternating in-plane polarization. EBSD mapping allowed for the spatially resolved correlation of the ferroelectric patterns and the crystal orientation within the MAPbI3 thin-films. Electrical simulations provide insight into the working principle of ferroelectric MAPbI3 solar cells. Poling experiments elucidate the impact of the ferroelectric microstructure on macroscopic device properties.

 

Altogether, these investigations provide micro-structural target properties for MAPbI3 thin-film deposition and outline pathways forward for more efficient, eco-friendly and lead-free perovskite solar cells.

 

Holger Röhm1,2,Tobias Leonhard1,2, Alexander D. Schulz1,2, Susanne Wagner2,3,

Michael J. Hoffmann2,3 and Alexander Colsmann1,2

 

1 Light Technology Institute, Karlsruhe Institute of Technology,

Karlsruhe, 76131, Germany.

2 Material Research Center for Energy Systems, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany.

3 Institute for Applied Materials – Ceramic Materials and Technologies,

Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany.

 

alexander.colsmann@kit.edu

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Ferroelectricity in methylammonium lead iodide perovskite solar cells

21.10.2019 von 16:00 bis 17:00

Among the emerging photovoltaic technologies, perovskite solar cells stand out with remarkable power conversion efficiencies (PCEs) and low-cost solution processability, rivaling established technologies. Currently, the scientific community controversially discusses the importance of the ferroic properties for the exceptional performance of MAPbI3 light-harvesting layers.

 

In this work, we performed a comprehensive AFM study including Piezoresponse Force Microscopy (PFM) and Kelvin Probe Force Microscopy (KPFM). On large flat crystals, we find 90 nm wide ferroelectric domains of alternating in-plane polarization. EBSD mapping allowed for the spatially resolved correlation of the ferroelectric patterns and the crystal orientation within the MAPbI3 thin-films. Electrical simulations provide insight into the working principle of ferroelectric MAPbI3 solar cells. Poling experiments elucidate the impact of the ferroelectric microstructure on macroscopic device properties.

 

Altogether, these investigations provide micro-structural target properties for MAPbI3 thin-film deposition and outline pathways forward for more efficient, eco-friendly and lead-free perovskite solar cells.

 

Holger Röhm1,2,Tobias Leonhard1,2, Alexander D. Schulz1,2, Susanne Wagner2,3,

Michael J. Hoffmann2,3 and Alexander Colsmann1,2

 

1 Light Technology Institute, Karlsruhe Institute of Technology,

Karlsruhe, 76131, Germany.

2 Material Research Center for Energy Systems, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany.

3 Institute for Applied Materials – Ceramic Materials and Technologies,

Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany.

 

alexander.colsmann@kit.edu

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Ferroelectricity in methylammonium lead iodide perovskite solar cells

21.10.2019 von 16:00 bis 17:00

Among the emerging photovoltaic technologies, perovskite solar cells stand out with remarkable power conversion efficiencies (PCEs) and low-cost solution processability, rivaling established technologies. Currently, the scientific community controversially discusses the importance of the ferroic properties for the exceptional performance of MAPbI3 light-harvesting layers.

 

In this work, we performed a comprehensive AFM study including Piezoresponse Force Microscopy (PFM) and Kelvin Probe Force Microscopy (KPFM). On large flat crystals, we find 90 nm wide ferroelectric domains of alternating in-plane polarization. EBSD mapping allowed for the spatially resolved correlation of the ferroelectric patterns and the crystal orientation within the MAPbI3 thin-films. Electrical simulations provide insight into the working principle of ferroelectric MAPbI3 solar cells. Poling experiments elucidate the impact of the ferroelectric microstructure on macroscopic device properties.

 

Altogether, these investigations provide micro-structural target properties for MAPbI3 thin-film deposition and outline pathways forward for more efficient, eco-friendly and lead-free perovskite solar cells.

 

Holger Röhm1,2,Tobias Leonhard1,2, Alexander D. Schulz1,2, Susanne Wagner2,3,

Michael J. Hoffmann2,3 and Alexander Colsmann1,2

 

1 Light Technology Institute, Karlsruhe Institute of Technology,

Karlsruhe, 76131, Germany.

2 Material Research Center for Energy Systems, Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany.

3 Institute for Applied Materials – Ceramic Materials and Technologies,

Karlsruhe Institute of Technology, Karlsruhe, 76131, Germany.

 

alexander.colsmann@kit.edu

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Kolloquiumsvortrag (ET/IT) von Priv. Doz. Dr. Alexander Colsmann, Head of Organic Photovoltaics Group KIT Energy Center Karlsruhe Institute of Technology (KIT)

21.10.2019 von 16:00 bis 16:00

Weitere Informationen finden Sie hier

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„Studieneingangswoche – engineers getting started“ - Angebot für Erstsemestler

07.10.2019 von 11:00 bis 12:00

Die Studieneingangswoche „engineers getting started“ ist eine fakultative Veranstaltung für alle Erstsemester der Bachelor-Studiengänge

  • Elektrotechnik und Informationstechnik (ET&IT)
  • des Wirtschaftsingenieurwesens ET&IT
  • der Materialwissenschaft (MaWi)
  • und des Wirtschaftsingenieurwesens MaWi

 

Ziel der Studieneingangswoche ist es, Sie auf die neuen Herausforderungen und die sich Ihnen bietenden Perspektiven vorzubereiten. Für die Studierenden der Elektrotechnik und Informationstechnik (ET&IT) und des Wirtschaftsingenieurwesens ET&IT schließt sich die Pflichtveranstaltung „Studieneingangsprojekt“ nahtlos an, die in der Folgewoche stattfindet. Die regulären Vorlesungen beginnen am 21.10.2019.

 

In der Studieneingangswoche engineers getting started werden Sie themenbezogen in verschiedenen Klein- und Großgruppen Ihr zukünftiges Studium ergründen. Hierbei werden Sie:

  • · die Rahmenbedingungen für Ihr Studium erarbeiten
  • · ein technisches System begreifen und dafür eigenständig technische Hintergründe recherchieren
  • · verschiedene Labore betreten und Fachgespräche führen
  • · den Campus der Universität und die wichtigsten Räume kennenlernen
  • · who is who – Ihre Mitstudierenden kennen- und schätzen lernen
  • · die Lehrstühle Ihres Fachgebietes und deren Forschung erleben
  • · mit Studierenden, Doktoranden, ProfessorenInnen und erfolgreichen IngenieurInnen ins Gespräch kommen
  • · Gemeinschaft erleben und Spass haben!

 

Voraussetzungen / Organisatorisches

 

Bitte nehmen Sie nach Möglichkeit einen voll aufgeladenen Laptop für die Recherchearbeiten mit. Weitere wichtige Dinge, die Ihr Rucksack beherbergen sollte, entnehmen Sie bitte der Packliste, die Sie in der OLAT-Instanz der Veranstaltung finden. Achten Sie darauf, dass Sie bereits Zugang zum WLAN-Netz der CAU hergestellt haben.
Die Studieneingangswoche engineers getting started findet in Räumen des CAU-Hauptcampus und in Räumen am Campus Ost statt. Die erste Veranstaltung ist am Montag, dem 07.10.2018, 9:00 - 17:00 Uhr im Hans-Geiger-Hörsaal, Leibnitzstrasse 13. Hier erhalten Sie wertvolle Einblicke in Ihr Studium und wir stellen Ihnen die verschiedenen Veranstaltungen der Woche vor. Die Anwesenheit am Montagvormittag 9:00 - 14:00 Uhr ist zwingend erforderlich, da Sie sich hier für die weiteren Veranstaltungen in der Woche verbindlich einschreiben. Sie können also aus den Angeboten wählen und müssen nicht zwingend das Gesamtpaket besuchen.

Im Laufe der Woche werden Sie verschiedene Lern- und Arbeitsformate kennenlernen. Betreut werden Sie dabei von Mitarbeitenden des TF Servicezentrums, KollegInnen von PerLe und Studierenden höherer Semester.

Ein detaillierter Wochenplan wird vor Veranstaltungsbeginn zur Verfügung gestellt.
Bitte melden Sie sich zur Veranstaltung „engineers getting started - Studieneingangswoche“ via OLAT an. Hierfür benötigen Sie Ihre stu-Mailadresse und das Passwort, welches Sie für Ihre direct directory gesetzt haben.

get started

 

 

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Speech Analysis for the Automatic Detection and Monitoring of Parkinson's Disease

23.09.2019 von 10:00 bis 11:00

Parkinson's disease (PD) is second most common neurodegenerative disorder worldwide. It affects the control of muscles and limbs in the body and typically has negative impact on the speech production. Other motor activities like handwriting and gait are also affected. This talk will start with a general description of several neurodegenerative disorders including PD, Alzheimer's, and Aphasia. Typical speech disorders suffered by PD patients will be discussed and a methodology to automatically model those symptoms is also introduced. The suitability of such a methodology for the automatic detection and monitoring of PD is also discussed. In the final part of the talk, an extension of the methodology is presented considering other bio signals like handwriting and gait.

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Speech Analysis for the Automatic Detection and Monitoring of Parkinson's Disease

23.09.2019 von 10:00 bis 11:00

Parkinson's disease (PD) is second most common neurodegenerative disorder worldwide. It affects the control of muscles and limbs in the body and typically has negative impact on the speech production. Other motor activities like handwriting and gait are also affected. This talk will start with a general description of several neurodegenerative disorders including PD, Alzheimer's, and Aphasia. Typical speech disorders suffered by PD patients will be discussed and a methodology to automatically model those symptoms is also introduced. The suitability of such a methodology for the automatic detection and monitoring of PD is also discussed. In the final part of the talk, an extension of the methodology is presented considering other bio signals like handwriting and gait.

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Speech Analysis for the Automatic Detection and Monitoring of Parkinson's Disease

23.09.2019 von 10:00 bis 11:00

Parkinson's disease (PD) is second most common neurodegenerative disorder worldwide. It affects the control of muscles and limbs in the body and typically has negative impact on the speech production. Other motor activities like handwriting and gait are also affected. This talk will start with a general description of several neurodegenerative disorders including PD, Alzheimer's, and Aphasia. Typical speech disorders suffered by PD patients will be discussed and a methodology to automatically model those symptoms is also introduced. The suitability of such a methodology for the automatic detection and monitoring of PD is also discussed. In the final part of the talk, an extension of the methodology is presented considering other bio signals like handwriting and gait.

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Inducing transitions between healthy and pathological brain states: insights from semi-empirical computational modeling

12.09.2019 von 16:00 bis 17:00

Human consciousness is correlated with the complexity of brain dynamics. The response of brain activity to external electromagnetic perturbations is a robust marker of the level of consciousness, both in physiological and pathological states. However, it is difficult to assess this response, and different approximations are adopted in practice. In my talk I will show how the development of semi-empirical models (i.e. fusion of dynamical systems with information obtained from structural and functional neuroimaging) allows to build "in silico brains" for the rehearsal of the response against different external perturbations. This freedom for virtual experimentation allows to investigate potential solutions to a much more difficult problem than diagnosis: the induction of transitions towards the state of ordinary wakefulness, one of the greatest challenges of contemporary neurology. While most of the examples provided in my talk will concern states of reduced awareness, the developed methodology can also be applied to other neurological and psychiatric conditions.

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Inducing transitions between healthy and pathological brain states: insights from semi-empirical computational modeling

12.09.2019 von 16:00 bis 17:00

Human consciousness is correlated with the complexity of brain dynamics. The response of brain activity to external electromagnetic perturbations is a robust marker of the level of consciousness, both in physiological and pathological states. However, it is difficult to assess this response, and different approximations are adopted in practice. In my talk I will show how the development of semi-empirical models (i.e. fusion of dynamical systems with information obtained from structural and functional neuroimaging) allows to build "in silico brains" for the rehearsal of the response against different external perturbations. This freedom for virtual experimentation allows to investigate potential solutions to a much more difficult problem than diagnosis: the induction of transitions towards the state of ordinary wakefulness, one of the greatest challenges of contemporary neurology. While most of the examples provided in my talk will concern states of reduced awareness, the developed methodology can also be applied to other neurological and psychiatric conditions.

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Inducing transitions between healthy and pathological brain states: insights from semi-empirical computational modeling

12.09.2019 von 16:00 bis 17:00

Human consciousness is correlated with the complexity of brain dynamics. The response of brain activity to external electromagnetic perturbations is a robust marker of the level of consciousness, both in physiological and pathological states. However, it is difficult to assess this response, and different approximations are adopted in practice. In my talk I will show how the development of semi-empirical models (i.e. fusion of dynamical systems with information obtained from structural and functional neuroimaging) allows to build "in silico brains" for the rehearsal of the response against different external perturbations. This freedom for virtual experimentation allows to investigate potential solutions to a much more difficult problem than diagnosis: the induction of transitions towards the state of ordinary wakefulness, one of the greatest challenges of contemporary neurology. While most of the examples provided in my talk will concern states of reduced awareness, the developed methodology can also be applied to other neurological and psychiatric conditions.

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Anschluß eines Fluxkompensators an einen Van der Graaf Generator

Experimental Pitfalls

17.07.2019 von 14:00 bis 15:00

We all run experiments to prove the value of what we do and to try to persuade others that our visualisations are not just pretty but have a useful function outside the research team. But designing and conducting experiments is full of pitfalls: equipment failure, limited participant pool, confounding factors, incomplete data etc. And results are often uncertain and always limited. In my 20+ years of running experiments, I have made numerous mistakes - I estimate that I have thrown away about as much data as I have published. In this talk, I discuss some of my failures, highlighting the things that went wrong.  As part of this, I discuss the value of conducting follow-on experiments, and the danger of relying on p-values.

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Things that communicate and decide autonomously

12.07.2019 von 14:00 bis 15:00

Access to the Internet and communication is a key driving force in our modern society. Today, connectivity and computing come to physical objects and places: Even traditionally simple objects such as step counters, thermostats, and light bulbs begin to enjoy wireless connectivity. Similarly, cars, production lines and medical equipment will become networked. Predictions indicate that smart, connected objects soon will outnumber today's traditional connected devices such as smartphones or PCs. By 2025 we expect to reach 50 billion connected devices. This is called the Internet of Things (IoT) and it aims to make our daily lives easier, safer, and more sustainable. The Internet of Things monitory and interacts with the physical world and allows for new applications such as smart power grids, intelligent transportation, or advanced automation in factories and homes. Many of these applications are mission and safety-critical: For example, when two autonomous vehicles approach an intersection, they have to coordinate within a split second on which car shall cross first. Similarly, a wireless glucose sensor must quickly and reliably exchange information with, for example, an insulin pump to ensure a patient’s well-being. As a result, applications require fast, distributed networking and data analysis to ensure reliable coordination and decision making. In my talk, I will give an introduction to the field, give an overview of the work of my group in the area, outline open research challenges and future directions.

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Towards Data Science: From Data to Patterns to Knowledge

12.07.2019 von 14:00 bis 14:00

Recent advances of sensor technologies and the new user mentality of generating and voluntarily sharing information produce a tremendous source of rich data. This data contains information which is very useful for an incredible number of applications enhancing studies for diverse fields of science, supporting the productivity in industry, and enabling advanced services for our society. A necessary building block for taking advantage from this vast amount of information is the development of efficient and effective searching and mining algorithms which is very challenging because of the

specific characteristic of the data that is often unstructured or complex structured, heterogeneous, dynamic, uncertain or incomplete.

Furthermore, entities in our real world need to be considered as a set of interacting or interrelated, multi-typed components. To make such data useful for diverse applications, advanced methods for managing and retrieving information, pattern mining, machine learning and knowledge discovery that can cope with the afore mentioned characteristic of data are necessary. In my talk, I will address some of these issues in the context of scientific applications. In addition, I will introduce current research activities on heterogeneous information networks for cross-domain data fusion and analysis with an outlook to future research opportunities.

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Understanding Mg corrosion and biocorrosion

08.07.2019 von 16:00 bis 17:00

Andrej Atrens1, Sean Johnston2, Zhiming Shi1 , Matthew S. Dargusch2

1The University of Queensland, Materials Engineering Division, School of Mechanical & Mining Engineering, Brisbane, Qld 4072, Australia; 2The University of Queensland, Centre for Advanced Materials Processing and Manufacturing (AMPAM), Brisbane, Qld 4072, Australia

Abstract:

The first part of this talk reviews the main factors that control Mg corrosion immersed in aqueous solutions: (i) crystallographic orientation, (ii) impurity concentration (particularly Fe), and the influence of heat treatment, (iii) second phases, (iv) corrosion product films on the alpha-phase. Measurement effects are also mentioned.

The second part deals with Mg alloys for biodegradable medical implants. Over the last decade, Mg alloys have progressed from a laboratory concept to significant clinical successes. For this application, corrosion which is normally an unwanted feature of Mg alloys, becomes critical for success. It is vital to understand and control the corrosion rate. In vitro research has identified the following factors as the most important: (a) the inorganic ions like calcium, chlorides, bicarbonates, phosphates; and (b) the organic compounds including proteins, amino acids and vitamins. The best estimates for Mg corrosion rates (based on in vitro measurements) are larger than the corrosion rates measured in vivo. This suggests that the Mg corrosion mechanism in vivo is not adequately characterized, or the in vivo environment is not equivalent to immersion in a solution as used in the in vitro experiments. In fact, recent examination of specimens  implanted subcutaneously into Sprague-Dawley rats indicated that the in vivo environment was not at all equivalent to immersion in a solution, but rather the environment could be better described as damp.

Prepared as an invited presentation to Symposium F: Biomaterials

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Evolutionary Computing for Problems with Dynamically Changing Constraints

08.07.2019 von 11:00 bis 12:00

Dynamic problems appear frequently in real-world applications such as
logistics for mining and are usually subject to a large set of
constraints. These constraints change over time due to changes in
resources and having algorithms that can deal with such dynamic changes
delivers direct benefit to decision makers. Evolutionary algorithms are
well suited for such dynamic problems as they can easily adapt to
changing environments. In this talk, I will report on some theoretical
and experimental investigations that we have carried out in the area of
evolutionary algorithms for problems with dynamic constraints. The focus
will be the classical knapsack problem and constrained submodular
functions where the given constraint bound changes over time.

Based on:

-V. Roostapour, A. Neumann, F. Neumann (2018): On the performance of
baseline evolutionary algorithms on the dynamic knapsack problem.
In: Parallel Problem Solving from Nature XV, PPSN 2018.

-V. Roostapour, A. Neumann, F. Neumann, T. Friedrich (2019): Pareto
optimization for subset selection with dynamic cost constraints.
In: Thirty-Third AAAI Conference on Artificial Intelligence, AAAI 2019.

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Near infrared fluorescent materials and sensors for biomedical applications

03.06.2019 um 16:00 bis 03.07.2019 um 17:00

In our research we investigate and create functional (nano)materials for biomedical applications. We are especially interested in 1D and 2D materials that provide novel photophysical properties such as near Infrared (nIR) fluorescence. The nIR range (800-1700 nm) of the spectrum is beneficial for optical applications because it falls into the tissue transparency window. One example of such a material are semiconducting single-walled carbon nanotubes (SWCNTs). SWCNTs fluoresce in the nIR and their optoelectronic properties are very sensitive to changes in the chemical environment and they are therefore versatile building blocks for biosensors. In my talk I will cover the following current research topics of my group:

1)    I will show fundamental insights into SWCNT photophysics and how capabilities of SWCNT-based fluorescent sensors can be enhanced. SWCNTs were for example conjugated to nanobodies that can be targeted in vivo to any Green Fluorescent Protein (GFP) moiety. These SWCNTs were used for single-particle tracking and microrheology measurements in living drosophila embryos.

2)    The corona phase around SWCNTs was tailored to enhance selectivity and photophysics of SWCNT-based sensors for the important neurotransmitters dopamine and serotonine. These sensors can be used to image neurotransmitter efflux from neuronal cells and blood cells.

3)    We introduce a novel class of 2D nIR fluorescent silicate nanosheets, characterize their photophysical properties as a function of their dimensionality and use them for in vivo particle tracking as well as standoff detection in living plants.

4)    Immune cells were used for programmed transport and release of nanoscale cargo. The cells take up SWCNT-based sensors, transport them and release them again.

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Revealing novel power laws and quantization in electrospinning considering jet splitting – towards predicting fiber diameter and its distribution

New Avenues for Exploration and Applications of Gallium Nitride and related materials

25.06.2019 von 15:00 bis 16:00

New Avenues for Exploration and Applications of Gallium Nitride and related materials

Ion Tiginyanu

Academy of Sciences and Technical University of Moldova, Chisinau, Republic of Moldova

Gallium nitride, a wide-bandgap semiconductor compound, has in the last two decades registered a fascinating increase in the crystalline quality of epitaxial layers determining its leading role in the development of the modern solid-state lighting industry. The demonstration and successful commercialization of GaN-based blue light emitting diodes resulted in the physics Nobel prize to I. Akasaki, H. Amano and S. Nakamura in 2014. Exhibiting an impressive number of unique properties, over the last decade GaN has been remarkably successful in the area of high-power/high-frequency electronic applications and is now considered the second most important semiconductor material after Silicon. In this paper, we report on new fields of research and applications of gallium nitride and related materials such as nano-biomedicine, nano-microfluidics, nano-microrobotics and memristor networks. The feasibility of high-performance light-driven nano/microengines based on GaN nano/microtubular structures will be demonstrated.

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All-optical magnetization switching in spin-valve structures mediated by spin-polarized hot electron transport

Energy-Aware Real-Time Task Scheduling on Local/Shared Memory Systems

17.06.2019

The rapid development of the Real-Time and Embedded System
(RTES) has increased the requirement on the processing capabilities of
sensors, mobile phones and smart devices, etc. Meanwhile, energy
efficiency techniques are in desperate need as most devices in RTES are
battery powered. Following the above two trends, this work explores the
memory system energy efficiency for a general multi-core architecture.
This architecture integrates a local memory in each processing core,
with a large off-chip memory shared among multiple cores. Decisions need
to be made on whether tasks will be executed with the shared memory or
the local memory to minimize the total energy consumption within
real-time constraints. This paper proposes optimal schemes as well as a
polynomial-time approximation algorithm with constant ratio.

Bio: Minming Li is currently an associate professor in the Department of
Computer Science, City University of Hong Kong. He received his Ph. D.
and B.E. degree in the Department of Computer Science and Technology at
Tsinghua University in 2006 and 2002 respectively. His research
interests include algorithmic game theory, combinatorial optimization
and algorithm design and analysis for scheduling problems.

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Direct water splitting by surface-conditioned n-GaP (100) photoanodes

12.06.2019 von 13:00 bis 14:00

Abstract

III-V semiconductors are candidates for photoelectrochemical (PEC) water splitting but they are prone to corrosion and suffer from corrosion-related decrease of efficiency. Gallium phosphide (GaP) has an indirect band gap of 2.26 eV which covers both the hydrogen evolution potential (HEP) and the oxygen evolution potential (OEP). Thus, in principle, GaP can be used as photocathode and photoanode. We have studied the structural and chemical surface modifications of n-GaP(100) photoanodes before and after extended PEC treatment by scanning electron microscopy (SEM), atomic force microscopy (AFM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). A 2±0.5 nm thin stable oxide film is produced at the surface of n-GaP(100) photoanode via oxidizing the surface at 0.8 V vs RHE (reversible hydrogen electrode) and subsequent hydrogenation to passivate the electrically active defects in the oxide film. After appropriate surface-conditioning, direct water splitting is demonstrated without any applied potential.

Indirect charge transfer from photoanode to electrolyte via interface states in oxide.

Direct water splitting by surface-conditioned n-GaP (100) photoanodes

During direct water splitting, charge transfer across n-GaP(100) photoanode-electrolyte interface is analyzed with electrochemical impedance spectroscopy (EIS). The Nyquist plots, measured with EIS, are reproduced with simulation of an equivalent electrical circuit. It is determined that during water splitting, the charge transfer from V.B of the photoanode to the electrolyte via interface states in the oxide. It is also determined that the direct water splitting is a 6-step charge transfer process, including 4-step water oxidation reaction.

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Broadband Ferromagnetic Resonance Spectroscopy: The “Swiss Army Knife” for Understanding Spin-Orbit Phenomena

Neuromorphic control

27.05.2019 von 14:15 bis 15:00

Neurophysiological circuits exhibit control properties unparalleled in man-made control systems. They combine sensitivity to the tiny and robustness to the large in an astonishing way, seemingly  paradoxical. They form control systems across scales, allowing sensing and actuation from the molecular scale up to the whole body scale. This talk will explore some of the basic feedback principles that allow for such properties. In particular, I will emphasize the key role of mixed feedback, which involves a  combination of positive and negative feedback, or excitation and inhibition, at every scale. I will then discuss the possibility of implementing such properties in neuromorphic circuits and discuss the potential of neuromorphic control in engineering.
 

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Activity Sensing and Localization in Indoor Enviroments

24.05.2019 von 14:00 bis 14:45

Sensing people and mobile objects in indoor environments are key
building blocks of many smart building applications. In this talk, I
will share some recent results from my research in indoor localization
and people sensing in buildings. We have developed new ways to use
ultra sonic sensing to count and track people in buildings while
ensuring privacy. We have made ultra-wide band radio based indoor
localization more accurate, efficient, and scalable. I will also
describe what we learned from evaluating these approaches on long and
short-term deployments in buildings and on testbeds.

Speaker Bio

Omprakash Gnawali is an Associate Professor at the Computer Science
Department of the University of Houston. He does research on IoT, with
a focus on wireless and sensing technologies. Other areas of interest
include cybersecurity, data analytics, mobile systems, and technology
for the emerging markets. He received his SB and MEng from MIT, PhD
from USC, and was a postdoc at Stanford.

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Kolloquium (Mawi) von Prof. Lutz Mädler, Universität Bremen

Medical diagnosis aided by automatic classification: Non-blackbox approaches for clinical voice assessment

06.05.2019 von 16:00 bis 17:30

Voice disorders are socially relevant, because they may lead to significant follow-up costs for health insurances and the economic system, if no adequate treatment is administered timely. Voice quality characterization is pivotal to the clinical care of voice disorders, because it aids the indication, selection, evaluation, and optimization of clinical treatment techniques, including speech therapy by administered by logopedists / speech language pathologists, and phonosurgery, performed by medical doctors specialized on voice disorders.

Current approaches to artificial intelligence, including (Deep) Neural Networks, are not fully accepted by clinical experts, partly due to their black box nature. In particular, explanatory power of these approaches is low. In contrast, we propose to use hand-crafted model based features as input to low-dimensional classification automats. Our features are meant to represent closely the properties of the voice, which are described on the level of voice production, on the level of acoustics, and on the level of perception.

Diplophonia is a particular type of pathological voice qualities, in which two simultaneous pitches are reported by clinical experts to be audible simultaneously. Diplophonia may be a symptom of a vocal dysfunction that needs medical treatment. The inherently subjective definition located on the domain of auditory perception is complemented by our approaches to track two simultaneous fundamental frequencies from high-speed videos of the vocal folds, and from audio signals. Also, first steps with a physiologically grounded hearing model are presented. The hearing model is used to predict from decomposed audio signals of the voice the presence of two simultaneously perceivable pitches.

 

Short bio:

Philipp Aichinger is a Research Associate of the Medical University of Vienna (MUV). He is affiliated with the Department of Otorhinolaryngology, Division of Phoniatrics-Logopedics. He graduated interdisciplinary studies in Electrical Engineering/Sound Engineering at the Graz University of Technology (TUG) and the University of Music and Dramatic Arts in Graz (KUG), acquiring expertise both in engineering and in music/perception research. His PhD-thesis "Diplophonic Voice - Definitions, models, and detection" has been supervised by the TUG and the MUV. Philipp is Principal InvestigPhillip Aichingerator of a research project FWF KLI722-B30 funded within the Program Clinical Research of the Austrian Science Fund (FWF), entitled “Objective differentiation of dysphonic voice quality types”. He is an organizer of the 2019 Special Session at Interspeech, entitled “Voice quality characterization for clinical voice assessment: Voice production, acoustics, and auditory perception”. He is a member of the IEEE Signal Processing Society, the Audio Engineering Society, and the Acoustical Society of America. He is reviewer for the Journal of the Acoustical Society of America, for the IEEE Transactions on Audio, Speech and Language Processing, for the Journal of Medical and Biological Engineering, for the Journal Biomedical Signal Processing and Control, and for Acta Acustica united with Acustica.

 

 

 

 

 

 

 

 

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Organic and bio-organic electronic devices

03.05.2019 von 13:00 bis 14:30

Organic electronic devices are maturing from the academic research into the industrial development, entering the markets. In order to account for a sustainable future, the application of biodegradable and biocompatible systems for organic optoelectronics are needed. The use of cheap electronic devices in a large scale will introduce a “consumable electronics” into the market of “consumer electronics”. Therefore environmentally friendly materials are important to use. This is a next great challenge to material science in organic electronics. New developments of bio-inspired and/or bio-origin, bio-compatible materials are interesting. Such materials can also be used to interface the biological and biomedical research with the organic electronics field.

 

Last but not least the conversion of CO2 to methane (or other synthetic fuels) using solar energy is an important step to make an efficient, large scale energy storage.  At the same time this will make a cyclic and sustainable CO2 economy. We report organic as well as bio-organic catalysts which can be used in photo-electro-catalytic conversion devices. Such bio-catalysts can be enzymes as well as living bacteria immobilized on electrodes. Selectivity of such bio-catalysts is very high and combined with the room temperature operation of such bio-electro-catalytic systems makes them industrially highly attractive.

 

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Thermal stability and diffusion phenomena in metal/semiconductor superlattice thin films observed by aberrationcorredted TEM-methods at atomic resolution

Kolloquium (INF) Prof. Dr. Petchporn Chawakitchareon, Environmental Engineering Department, Chulalongkorn University Bangkok

09.04.2019 von 17:00 bis 18:30

Water Quality Index Analysis and Prediction

Artificial neural network is a common method which has been used in many
data science projects. This talk presents a comparison of prediction
methods for water quality indexes using for classifying the water
quality in rivers or canals. We compare data analysis and data mining
results that can be obtained on the basis of full data records obtained
in Thailand for the decade 2007-2017. Special attention is directed
towards M5P, M5Rules and REPTree analysis algorithms compared to results
from multilayer perceptron - one type of artificial neural network. Our
experimental results show that the REPTree method yielded the highest
accuracy to predict Water quality indexes comparing to other methods.
For M5P and M5Rules, building models by using smoothing procedures and
unpruned techniques appears to give out the best model to predict with
the highest accuracy.

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Sonderkolloquium (Mawi) von Jochen Schmitt, Analog Devices International

In situ TEM and x-ray spectroscopy studies of perovskite oxide electrodes for electrochemical water oxidation

"From Davis’ law to modern mechanobiology: how mechanics governs growth of soft biological tissues"

Modellierung und Simulation von Materialien im Großen und im Kleinen

Topics in circuit design for biomedical sensing

Power supply for wireless sensors systems

Flexibilitätsoptionen für das industrielle Net-Zero Energieversorgungs-Mikronetz: eine technische und ökonomische Bewertung

Satellitennavigation als Basis für Hochgenaue und Robuste Zustandsschätzung für Autonome Vehikel

Sonderkolloquium (Mawi) von Elizaveta V. Golubeva, Ural Federal University of Ekaterinburg

Nanostructured films and polymer composites of Graphene and Two-dimensional Materials: electrical and mechanical properties and applications in wearable bio-sensors.

(M)Ein Weg nach der Promotion! Von Möglichkeiten und Grenzen

Hören für Alle: Von der empirischen Hörforschung zur modernen Präzisions-Audiologie

Ferroelectric Hafnium and Zirconium Oxide: Enablers for New Device Concepts

Multiphase Induction Motor Drives

A Laser in a Living Cell – Cellular scale photonics for optical sensing, tracking and manipulation

Word occurrence counts in stochastic string rewriting systems

From Constellation Shaping to Nonlinear Fourier Transform – On the Way to the Limits of Optical Data Links!?

Hybrid Spintronic-CMOS Microsystems – From Wearables to Implantables

Use of "Should" or "Should Not"

Kommunikation mit Außerirdischen unter Nutzung einfacher Digitaltechnik

Kolloquiumsvortrag (ET/IT), Prof. Sawodny, Institut für Systemdynamik, Universität Stuttgart / am 16.07.2018

16.07.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Methoden der Systemdynamik in der Optomechatronik
 

Abstract:  Im Vortrag werden anhand verschiedener Beispiele die Anwendung von Methoden der Systemdynamik auf Fragestellungen in der Optomechatronik vorgestellt. Diese findet vorzugsweise in der adaptiven Optik eine Anwendung. Nach einer kurzen Einführung in die grundsätzliche Thematik der adaptiven Optik werden Anwendungen im Kontext der Großteleskope vorgestellt. Hier werden verschiedene Ansätze wie beispielsweise zur Abbildungsverbesserung durch vorsteuernde Vibrationskompensation und eine Methode zur thermischen Drift-Kompensation präsentiert. Auch atmosphäreninduzierte Fehler können durch geeignete Modellierung und Methoden der Störgrößenkompensation wirksam unterdrückt werden. Abschließend werden Ansätze zur Modellierung und Steuerung adaptiver optischer Elemente in Laserresonatoren vorgestellt.

Prof. Meurer

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Kolloquiumsvortrag (ET/IT), Prof. Sawodny, Institut für Systemdynamik, Universität Stuttgart / am 16.07.2018

16.07.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Methoden der Systemdynamik in der Optomechatronik
 

Abstract:  Im Vortrag werden anhand verschiedener Beispiele die Anwendung von Methoden der Systemdynamik auf Fragestellungen in der Optomechatronik vorgestellt. Diese findet vorzugsweise in der adaptiven Optik eine Anwendung. Nach einer kurzen Einführung in die grundsätzliche Thematik der adaptiven Optik werden Anwendungen im Kontext der Großteleskope vorgestellt. Hier werden verschiedene Ansätze wie beispielsweise zur Abbildungsverbesserung durch vorsteuernde Vibrationskompensation und eine Methode zur thermischen Drift-Kompensation präsentiert. Auch atmosphäreninduzierte Fehler können durch geeignete Modellierung und Methoden der Störgrößenkompensation wirksam unterdrückt werden. Abschließend werden Ansätze zur Modellierung und Steuerung adaptiver optischer Elemente in Laserresonatoren vorgestellt.

Prof. Meurer

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Kolloquiumsvortrag, Prof. King,TU Berlin / am 09.07.2018

09.07.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Closed-loop active flow control of repetitive disturbances in a linear stator cascade

Abstract: This presentation demonstrates the mitigation of disturbances in a periodically throttled compressor stator cascade by closed-loop active flow control. The work is motivated by the replacement of a constant pressure combustion of a gas turbine with the significantly more efficient constant volume counterpart. One way of implementing a constant volume combustion is a pulse detonation engine. In such an engine, the heat addition takes place in a discontinuous, detonative manner while the inlets to the combustion tubes are closed. As a result, periodic pressure waves will be transmitted upstream into the compressor. A successful exploitation of this new combustion system therefore strongly depends on the ability to dampen negative effects resulting from these disturbances. To this end, active flow control is applied based on two different actuators for the sidewalls and the blade. Blowing fluidic switches are used to excite flow modes to decrease detrimental corner vortices and premature flow separation. For closed-loop control, the repetitive nature of the disturbances can be utilized to increase control performance. Three concepts will be considered here and compared. In iterative learning control (ILC), either in a frequency-based or time-based formulation, un-modeled nonlinear effects and disturbances are learned over the cycles to some extent and used to adapt the control inputs. As an alternative, repetitive model predictive control (RMPC) is introduced which more directly makes use of remaining control errors of a last cycle. RMPC and one of the ILC formulations, which solve respective optimization problems on-line, outperformed the considered frequency-based version of classical ILC with respect to control performance. However, the frequency domain ILC variant might benefit from its robustness features.
 

Prof.Meurer

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Kolloquiumsvortrag, Prof. King,TU Berlin / am 09.07.2018

09.07.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Closed-loop active flow control of repetitive disturbances in a linear stator cascade

Abstract: This presentation demonstrates the mitigation of disturbances in a periodically throttled compressor stator cascade by closed-loop active flow control. The work is motivated by the replacement of a constant pressure combustion of a gas turbine with the significantly more efficient constant volume counterpart. One way of implementing a constant volume combustion is a pulse detonation engine. In such an engine, the heat addition takes place in a discontinuous, detonative manner while the inlets to the combustion tubes are closed. As a result, periodic pressure waves will be transmitted upstream into the compressor. A successful exploitation of this new combustion system therefore strongly depends on the ability to dampen negative effects resulting from these disturbances. To this end, active flow control is applied based on two different actuators for the sidewalls and the blade. Blowing fluidic switches are used to excite flow modes to decrease detrimental corner vortices and premature flow separation. For closed-loop control, the repetitive nature of the disturbances can be utilized to increase control performance. Three concepts will be considered here and compared. In iterative learning control (ILC), either in a frequency-based or time-based formulation, un-modeled nonlinear effects and disturbances are learned over the cycles to some extent and used to adapt the control inputs. As an alternative, repetitive model predictive control (RMPC) is introduced which more directly makes use of remaining control errors of a last cycle. RMPC and one of the ILC formulations, which solve respective optimization problems on-line, outperformed the considered frequency-based version of classical ILC with respect to control performance. However, the frequency domain ILC variant might benefit from its robustness features.
 

Prof.Meurer

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Kolloquiumsvortrag, Leon Abelmann, "KIST Europe" und "University of Twente" am 02.07.2018

02.07.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Observing magnetic objects in fluids

Abstract: At KIST Europe, we specialize in studying magnetic objects in a fluid enviroment. The objects I would like to present are

-Magneto-tactic bacteria, which we observe for instance inside a microfluidic chip (https://youtu.be/3uUL4ooM6KI)

- 3D printed centimeter sized objects with embedded magnets inside a turbulent water flow, which we use to study self-assembly processes (https://youtu.be/8NleFldyf50)

- Supsensions of microfabricated permalloy discs with diameters of 150-3000 nm, which might be a better alternative to magnetic colloids for magnetic particle imaging (https://journal.iwmpi.org/index.php/iwmpi/article/view/76)

Prof. McCord

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Kolloquiumsvortrag, Leon Abelmann, "KIST Europe" und "University of Twente" am 02.07.2018

02.07.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Observing magnetic objects in fluids

Abstract: At KIST Europe, we specialize in studying magnetic objects in a fluid enviroment. The objects I would like to present are

-Magneto-tactic bacteria, which we observe for instance inside a microfluidic chip (https://youtu.be/3uUL4ooM6KI)

- 3D printed centimeter sized objects with embedded magnets inside a turbulent water flow, which we use to study self-assembly processes (https://youtu.be/8NleFldyf50)

- Supsensions of microfabricated permalloy discs with diameters of 150-3000 nm, which might be a better alternative to magnetic colloids for magnetic particle imaging (https://journal.iwmpi.org/index.php/iwmpi/article/view/76)

Prof. McCord

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Kolloquiumsvortrag (MAWI), Iain Dunlop, Imperial College London / am 25.06.2018

25.06.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Engineering the immune system with graphitic nanomaterials

Abstract: Recent work shows that immune cell signalling is controlled by supramolecular assemblies of molecules on the c. 100 nm scale.  This insight offers the possibility of developing new nano-scale reagents to direct immune cell activation. We have used nano-flakes of graphene oxide as templates to develop molecular nanoclusters of monoclonal antibodies (mAb) that stimulate immune cells. This technology is applied to Natural Killer (NK) cells: a key cell type in the body’s natural anti-cancer defences. The nanoclusters successfully activate NK cells, enhancing the potency of the clustered mAb. This demonstrates molecular nanoclustering as a powerful approach to developing new immunomodulatory reagents with graphene oxide -templated nanoclusters a strong candidate technology.

Prof. Selhuber

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Kolloquiumsvortrag (MAWI), Iain Dunlop, Imperial College London / am 25.06.2018

25.06.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Engineering the immune system with graphitic nanomaterials

Abstract: Recent work shows that immune cell signalling is controlled by supramolecular assemblies of molecules on the c. 100 nm scale.  This insight offers the possibility of developing new nano-scale reagents to direct immune cell activation. We have used nano-flakes of graphene oxide as templates to develop molecular nanoclusters of monoclonal antibodies (mAb) that stimulate immune cells. This technology is applied to Natural Killer (NK) cells: a key cell type in the body’s natural anti-cancer defences. The nanoclusters successfully activate NK cells, enhancing the potency of the clustered mAb. This demonstrates molecular nanoclustering as a powerful approach to developing new immunomodulatory reagents with graphene oxide -templated nanoclusters a strong candidate technology.

Prof. Selhuber

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Kolloquiumsvortrag (MAWI), Nian. X Sun W.M. Keck Laboratory for Integrated Ferroics, & ECE Department, Northeastern University, Boston, / am 18.06.2018

18.06.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: RF NEMS Magnetoelectric Sensors

Abstract: The coexistence of electric polarization and magnetization in multiferroic materials provides great opportunities for realizing magnetoelectric coupling, including electric field control of magnetism, or vice versa, through a strain mediated magnetoelectric coupling in layered magnetic/ferroelectric multiferroic heterostructures [1-9]. Strong magnetoelectric coupling has been the enabling factor for different multiferroic devices, which however has been elusive, particularly at RF/microwave frequencies. In this presentation, I will cover the most recent progress on new integrated magnetoelectric materials, magnetoelectric NEMS (nanoelectromechanical system) based sensors and antennas. Specifically, we will introduce magnetoelectric multiferroic materials, and their applications in different devices, including: (1) novel ultra-compact RF NEMS acoustic magnetoelectric antennas immune from ground plane effect with < l0/100 in size, self-biased operation and potentially 1~2% voltage tunable operation frequency; and (2) ultra-sensitive RF NEMS magnetoelectric magnetometers with ultra-low noise of ~1pT/Hz1/2 at 10 Hz for DC and AC magnetic fields sensing. These novel magnetoelectric devices show great promise for applications in compact, lightweight and power efficient sensors and sensing systems, ultra-compact antennas and for radars, communication systems, biomedical devices, IoT, etc.

Reference: 1. N.X. Sun and G. Srinivasan, SPIN, 02, 1240004 (2012); 2. J. Lou, et al., Advanced Materials, 21, 4711 (2009); 3. J. Lou, et al. Appl. Phys. Lett. 94, 112508 (2009); 4. M. Liu, et al. Advanced Functional Materials, 21, 2593 (2011); 5. T. Nan, et al. Scientific Reports, 3, 1985 (2013); 6. M. Liu, et al. Advanced Materials, 25, 1435 (2013); 7. M. Liu, et al. Advanced Functional Materials, 19, 1826 (2009); 8. Ziyao Zhou, et al. Nature Communications, 6, 6082 (2015). 9. T. Nan, et al. Nature Comm. 8, 296 (2017).

Short Bio: Nian Sun is professor at the Electrical and Computer Engineering Department, Director of the W.M. Keck Laboratory for Integrated Ferroics, Northeastern University, and Thrust Leader of 2-D Multiferroics in the NSF ERC Transitional Applications of Nanoscale Multiferroic Systems (TANMS). He received his Ph.D. degree from Stanford University. Prior to joining Northeastern University, he was a Scientist at IBM and Hitachi Global Storage Technologies. Dr. Sun was the recipient of the NSF CAREER Award, ONR Young Investigator Award, the Søren Buus Outstanding Research Award, etc. His research interests include novel magnetic, ferroelectric and multiferroic materials, devices and subsystems. He has over 240 publications and over 20 patents and patent applications. One of his papers was selected as the “ten most outstanding full papers in the past decade (2001~2010) in Advanced Functional Materials”. Dr. Sun has given over 100 plenary or invited presentations and seminars in national and international conferences and universities. He is an editor of Sensors, and IEEE Transactions on Magnetics, and a fellow of the Institute of Physics, and of the Institution of Engineering and Technology.

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Kolloquiumsvortrag (MAWI), Nian. X Sun W.M. Keck Laboratory for Integrated Ferroics, & ECE Department, Northeastern University, Boston, / am 18.06.2018

18.06.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: RF NEMS Magnetoelectric Sensors

Abstract: The coexistence of electric polarization and magnetization in multiferroic materials provides great opportunities for realizing magnetoelectric coupling, including electric field control of magnetism, or vice versa, through a strain mediated magnetoelectric coupling in layered magnetic/ferroelectric multiferroic heterostructures [1-9]. Strong magnetoelectric coupling has been the enabling factor for different multiferroic devices, which however has been elusive, particularly at RF/microwave frequencies. In this presentation, I will cover the most recent progress on new integrated magnetoelectric materials, magnetoelectric NEMS (nanoelectromechanical system) based sensors and antennas. Specifically, we will introduce magnetoelectric multiferroic materials, and their applications in different devices, including: (1) novel ultra-compact RF NEMS acoustic magnetoelectric antennas immune from ground plane effect with < l0/100 in size, self-biased operation and potentially 1~2% voltage tunable operation frequency; and (2) ultra-sensitive RF NEMS magnetoelectric magnetometers with ultra-low noise of ~1pT/Hz1/2 at 10 Hz for DC and AC magnetic fields sensing. These novel magnetoelectric devices show great promise for applications in compact, lightweight and power efficient sensors and sensing systems, ultra-compact antennas and for radars, communication systems, biomedical devices, IoT, etc.

Reference: 1. N.X. Sun and G. Srinivasan, SPIN, 02, 1240004 (2012); 2. J. Lou, et al., Advanced Materials, 21, 4711 (2009); 3. J. Lou, et al. Appl. Phys. Lett. 94, 112508 (2009); 4. M. Liu, et al. Advanced Functional Materials, 21, 2593 (2011); 5. T. Nan, et al. Scientific Reports, 3, 1985 (2013); 6. M. Liu, et al. Advanced Materials, 25, 1435 (2013); 7. M. Liu, et al. Advanced Functional Materials, 19, 1826 (2009); 8. Ziyao Zhou, et al. Nature Communications, 6, 6082 (2015). 9. T. Nan, et al. Nature Comm. 8, 296 (2017).

Short Bio: Nian Sun is professor at the Electrical and Computer Engineering Department, Director of the W.M. Keck Laboratory for Integrated Ferroics, Northeastern University, and Thrust Leader of 2-D Multiferroics in the NSF ERC Transitional Applications of Nanoscale Multiferroic Systems (TANMS). He received his Ph.D. degree from Stanford University. Prior to joining Northeastern University, he was a Scientist at IBM and Hitachi Global Storage Technologies. Dr. Sun was the recipient of the NSF CAREER Award, ONR Young Investigator Award, the Søren Buus Outstanding Research Award, etc. His research interests include novel magnetic, ferroelectric and multiferroic materials, devices and subsystems. He has over 240 publications and over 20 patents and patent applications. One of his papers was selected as the “ten most outstanding full papers in the past decade (2001~2010) in Advanced Functional Materials”. Dr. Sun has given over 100 plenary or invited presentations and seminars in national and international conferences and universities. He is an editor of Sensors, and IEEE Transactions on Magnetics, and a fellow of the Institute of Physics, and of the Institution of Engineering and Technology.

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Kolloquiumsvortrag (MAWI), Jan Lammerding, Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology Cornell University/ am 11.06.2018

11.06.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Squish and squeeze – Nuclear mechanics and mechanotransduction in physiology and disease

Abstract: The nucleus is the characteristic feature of eukaryotic cells and houses the genomic information of the cell. The Lammerding laboratory is combining cell and molecular biology approaches with microfabricated devices that mimic physiological environments, live-cell microscopy, and in vivo models to investigate how physical forces acting on the nucleus, for example, in contracting muscle cells or during migration of cells through tight interstitial spaces, can challenge the integrity of the nucleus, alter its structure, and cause genomic and transcriptional changes. These processes play important roles in cellular mechanotransduction, i.e., the ability of cells to convert mechanical stimuli into biochemical signals, but can also contribute to various diseases when the nuclear structure is perturbed by mutations or altered protein expression. In particular, mutations in the nuclear envelope proteins lamin A/C are responsible for a broad spectrum of diseases (laminopathies), including Emery-Dreifuss muscular dystrophy (EDMD) and dilated cardiomyopathy. The fact that most mutations result in highly tissue-specific disease phenotypes primarily affecting skeletal and cardiac muscles, in spite of the near ubiquitous expression of lamins A/C, suggest that lamin mutations may render cells more sensitive to mechanical stress, which then causes progressive cell failure in mechanically stressed tissues. I will discuss our recent findings that highlight the importance of lamins A/C in mediating nuclear stability and mechanotransduction in mechanically stressed cells and tissues. At the same time, increased nuclear deformability, caused for example by reduced levels of lamins A/C, can promote cell migration through tight spaces with cross-sections smaller than the nuclear diameter, where the large size and rigidity of the nucleus can constitute a rate-limiting factor. I will present recent findings that demonstrate the importance of nuclear mechanics during cell migration in confined environments in vitro and in vivo, as well as the functional consequences of cells having to squeeze their large nuclei through tight interstitial spaces and small pores in the extracellular matrix network, with a particular focus on breast cancer.

Prof. Selhuber

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Kolloquiumsvortrag (MAWI), Jan Lammerding, Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology Cornell University/ am 11.06.2018

11.06.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Squish and squeeze – Nuclear mechanics and mechanotransduction in physiology and disease

Abstract: The nucleus is the characteristic feature of eukaryotic cells and houses the genomic information of the cell. The Lammerding laboratory is combining cell and molecular biology approaches with microfabricated devices that mimic physiological environments, live-cell microscopy, and in vivo models to investigate how physical forces acting on the nucleus, for example, in contracting muscle cells or during migration of cells through tight interstitial spaces, can challenge the integrity of the nucleus, alter its structure, and cause genomic and transcriptional changes. These processes play important roles in cellular mechanotransduction, i.e., the ability of cells to convert mechanical stimuli into biochemical signals, but can also contribute to various diseases when the nuclear structure is perturbed by mutations or altered protein expression. In particular, mutations in the nuclear envelope proteins lamin A/C are responsible for a broad spectrum of diseases (laminopathies), including Emery-Dreifuss muscular dystrophy (EDMD) and dilated cardiomyopathy. The fact that most mutations result in highly tissue-specific disease phenotypes primarily affecting skeletal and cardiac muscles, in spite of the near ubiquitous expression of lamins A/C, suggest that lamin mutations may render cells more sensitive to mechanical stress, which then causes progressive cell failure in mechanically stressed tissues. I will discuss our recent findings that highlight the importance of lamins A/C in mediating nuclear stability and mechanotransduction in mechanically stressed cells and tissues. At the same time, increased nuclear deformability, caused for example by reduced levels of lamins A/C, can promote cell migration through tight spaces with cross-sections smaller than the nuclear diameter, where the large size and rigidity of the nucleus can constitute a rate-limiting factor. I will present recent findings that demonstrate the importance of nuclear mechanics during cell migration in confined environments in vitro and in vivo, as well as the functional consequences of cells having to squeeze their large nuclei through tight interstitial spaces and small pores in the extracellular matrix network, with a particular focus on breast cancer.

Prof. Selhuber

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Kolloquiumsvortrag (MAWI), Prof. Dr. Ulrich Schwarz,Heidelberg University, Institute for Theoretical Physics am 04.06.2018

04.06.2018 von 16:00 bis 16:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Cells and tissue as active materials

Abstract:

Biological systems such as cells and tissue use non-equilibrium processes to actively generate mechanical stress, movement and growth. Some of these processes can actually be reconstituted in biomimetic experiments with active soft matter. In this talk, we first discuss why and how contractile forces are generated by biological systems and how they can be measured, for example on soft elastic substrates. We then discuss how these contractile systems can be mathematically described by classical continuum mechanics extended by active elements. We finally explain how the local contractility of cells and tissue can be controled with optogenetics, and how the resulting forces and flows can be used to estimate their material properties.

Prof. Selhuber

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Kolloquiumsvortrag (MAWI), Prof. Dr. Ulrich Schwarz,Heidelberg University, Institute for Theoretical Physics am 04.06.2018

04.06.2018 von 16:00 bis 16:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Cells and tissue as active materials

Abstract:

Biological systems such as cells and tissue use non-equilibrium processes to actively generate mechanical stress, movement and growth. Some of these processes can actually be reconstituted in biomimetic experiments with active soft matter. In this talk, we first discuss why and how contractile forces are generated by biological systems and how they can be measured, for example on soft elastic substrates. We then discuss how these contractile systems can be mathematically described by classical continuum mechanics extended by active elements. We finally explain how the local contractility of cells and tissue can be controled with optogenetics, and how the resulting forces and flows can be used to estimate their material properties.

Prof. Selhuber

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Kolloquiumsvortrag (INF), Dr. Matthias Mnich, Uni Bonn / am 01.06.2018

01.06.2018 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Multivariate Algorithms for Machine Scheduling Problems

Abstract: Machine scheduling problems are a long-time key domain of algorithms and complexity research.  In those problems, we are generally given a finite set J of jobs with certain characteristics, and we must find a schedule for processing the jobs on one or more machines, which also may have their individual specifications. Typical characteristics of a job are its processing time, its release date, its due date, or its importance reflected by an integer weight. A significant amount of research has been devoted in the past 60 years towards designing polynomial-time algorithms which approximate the value of optimal schedules (for various objective functions). A novel approach to machine scheduling problems are multivariate algorithms, which aim to find a provably optimal schedule at the expense of an increased run time, which is permitted to depend moderately exponentially on the job characteristics or other structural parameters. We survey some recent algorithms in this paradigm, present some novel results, and discuss several challenging open problems in this exciting research area.

Prof. Jansen

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Kolloquiumsvortrag (INF), Dr. Matthias Mnich, Uni Bonn / am 01.06.2018

01.06.2018 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Multivariate Algorithms for Machine Scheduling Problems

Abstract: Machine scheduling problems are a long-time key domain of algorithms and complexity research.  In those problems, we are generally given a finite set J of jobs with certain characteristics, and we must find a schedule for processing the jobs on one or more machines, which also may have their individual specifications. Typical characteristics of a job are its processing time, its release date, its due date, or its importance reflected by an integer weight. A significant amount of research has been devoted in the past 60 years towards designing polynomial-time algorithms which approximate the value of optimal schedules (for various objective functions). A novel approach to machine scheduling problems are multivariate algorithms, which aim to find a provably optimal schedule at the expense of an increased run time, which is permitted to depend moderately exponentially on the job characteristics or other structural parameters. We survey some recent algorithms in this paradigm, present some novel results, and discuss several challenging open problems in this exciting research area.

Prof. Jansen

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Kolloquiumsvortrag (MaWi), Prof. Richard Fu, Faculty of Engineering and Environment, Northumbria University, Newcastle / am 28.05.2018

28.05.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Acoustic wave lab-on-chip is now flexible, bendable and potentially wearable!

Abstract: Thin film acoustic wave devices especially surface acoustic waves (SAW) have been used for sample preparation (sorting, separating, mixing, nebulization and dispensing) as well as bio-sensing. This talk will focus on our recent work of flexible and wearable thin film acoustic wave lab-on-chip (mainly using ZnO and AlN films on flexible substrates) for acoustic wave based microfluidic applications. We report theoretical and experimental studies of the evolution, hybridization and decoupling of wave modes in the flexible acoustic wave devices, as well as their vibration patterns. thus providing a guide for different microfluidic applications. Thin film based flexible SAW devices have the potential to be integrated with other microfluidic and sensing technology on flexible substrates including CMOS integrated circuits to make novel lab-on-chip for bio-detection for wearable and flexible applications. SAW devices on commercial polymer and aluminum foils have been fabricated and various microfluidic functions, such as mixing, pumping, jetting have been demonstrated with bent and deformed acoustic wave devices.

About Prof. Richard Fu. He has extensive experience in smart thin film/materials, biomedical microdevices, lab-on-chip, micromechanics, MEMS, nanotechnology, sensors and microfluidics. He has established a good reputation from his pioneer research work on shape memory films, piezoelectric thin films, nanostructured composite/films for applications in MEMS, sensing and energy applications. He published over 330 science citation index (SCI) journal papers (including Progress in Materials Science and Nature Communications), 2 books, 20 book chapters, and over 120 conference papers. His current SCI H-index is 39 with over 6500 citations. He is associate editor/editorial board members for seven international journals including Scientific Report. He is regular journal paper reviewers for more than 30 journals, and has co-organized 12 international conferences worldwide, and co-edited six special issues for journals.

Prof. Quandt

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Kolloquiumsvortrag (MaWi), Prof. Richard Fu, Faculty of Engineering and Environment, Northumbria University, Newcastle / am 28.05.2018

28.05.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Acoustic wave lab-on-chip is now flexible, bendable and potentially wearable!

Abstract: Thin film acoustic wave devices especially surface acoustic waves (SAW) have been used for sample preparation (sorting, separating, mixing, nebulization and dispensing) as well as bio-sensing. This talk will focus on our recent work of flexible and wearable thin film acoustic wave lab-on-chip (mainly using ZnO and AlN films on flexible substrates) for acoustic wave based microfluidic applications. We report theoretical and experimental studies of the evolution, hybridization and decoupling of wave modes in the flexible acoustic wave devices, as well as their vibration patterns. thus providing a guide for different microfluidic applications. Thin film based flexible SAW devices have the potential to be integrated with other microfluidic and sensing technology on flexible substrates including CMOS integrated circuits to make novel lab-on-chip for bio-detection for wearable and flexible applications. SAW devices on commercial polymer and aluminum foils have been fabricated and various microfluidic functions, such as mixing, pumping, jetting have been demonstrated with bent and deformed acoustic wave devices.

About Prof. Richard Fu. He has extensive experience in smart thin film/materials, biomedical microdevices, lab-on-chip, micromechanics, MEMS, nanotechnology, sensors and microfluidics. He has established a good reputation from his pioneer research work on shape memory films, piezoelectric thin films, nanostructured composite/films for applications in MEMS, sensing and energy applications. He published over 330 science citation index (SCI) journal papers (including Progress in Materials Science and Nature Communications), 2 books, 20 book chapters, and over 120 conference papers. His current SCI H-index is 39 with over 6500 citations. He is associate editor/editorial board members for seven international journals including Scientific Report. He is regular journal paper reviewers for more than 30 journals, and has co-organized 12 international conferences worldwide, and co-edited six special issues for journals.

Prof. Quandt

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Kolloquiumsvortrag (INF), Dr. Hermann Lindhorst, Fachanwalt für IT-Recht / am 25.05.2018

25.05.2018 von 14:15 bis 15:45

Christian-Albrechts-Platz 2, 24118 Kiel, Raum: Hörsaal A

Titel:  „Datenschutz: Anbruch eines neuen Zeitalters? – Zur Geltung der EU-Datenschutzgrundverordnung ab dem 25. Mai"

Abstract: Ab dem 25.5.2018 haben alle Bürger, Behörden und Unternehmen neue Vorschriften zum Datenschutz zu beachten, denn dann gelten europaweit die Regelungen der „EU-Datenschutzgrundverordnung“ sowie in Deutschland ein Bundesdatenschutzgesetz, bei dem nicht ein einziger Paragraph so wie vorher geblieben ist. Darauf weisen seit Monaten nicht nur Datenschützer, sondern auch viele andere hin, wie z.B. Unternehmensberater, Rechtsanwälte und Zertifizierungsunternehmen wie der TÜV. Doch was wird sich ab Ende Mail tatsächlich ändern? Hat vor dem Hintergrund z.B. der drastisch erhöhten Sanktionen ein echtes Umdenken stattgefunden oder bleibt der Datenschutz eine ungeliebte bürokratische Bürde?

 

wha@informatik.uni-kiel.de

Prof. Hasselbring

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Kolloquiumsvortrag (INF), Dr. Hermann Lindhorst, Fachanwalt für IT-Recht / am 25.05.2018

25.05.2018 von 14:15 bis 15:45

Christian-Albrechts-Platz 2, 24118 Kiel, Raum: Hörsaal A

Titel:  „Datenschutz: Anbruch eines neuen Zeitalters? – Zur Geltung der EU-Datenschutzgrundverordnung ab dem 25. Mai"

Abstract: Ab dem 25.5.2018 haben alle Bürger, Behörden und Unternehmen neue Vorschriften zum Datenschutz zu beachten, denn dann gelten europaweit die Regelungen der „EU-Datenschutzgrundverordnung“ sowie in Deutschland ein Bundesdatenschutzgesetz, bei dem nicht ein einziger Paragraph so wie vorher geblieben ist. Darauf weisen seit Monaten nicht nur Datenschützer, sondern auch viele andere hin, wie z.B. Unternehmensberater, Rechtsanwälte und Zertifizierungsunternehmen wie der TÜV. Doch was wird sich ab Ende Mail tatsächlich ändern? Hat vor dem Hintergrund z.B. der drastisch erhöhten Sanktionen ein echtes Umdenken stattgefunden oder bleibt der Datenschutz eine ungeliebte bürokratische Bürde?

 

wha@informatik.uni-kiel.de

Prof. Hasselbring

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Kolloquiumsvortrag (MAWI), Prof. Xian (Sherry) Chen, Hong Kong University of Science and Technology, / am 14.05.2018

14.05.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel:  Enhanced fatigue properties of phase-transforming materials by satisfying the cofactor conditions
 

Abstract:

Materials undergoing reversible solid-solid phase transformations provide emerging applications such as biomedical implants and stents, microelectronic actuators and sensors. The essential functionality of these materials is the ability to recover large deformation (i.e. 5~8%) before and after the structural transformation driven by temperature/stress/electromagnetic fields. The change of the lattice parameters and the breaking of symmetries, in turn, will cause the formation of microstructures, which lead to the accumulation of intrinsic defects at the stressed transition layer between phases.  It has been theorized that the macroscopic behaviors strongly depend on the kinematic properties of the transition layer between phases. If the lattice parameters satisfy some special mathematical conditions (the cofactor conditions), we observe that the functional fatigue properties of the phase-transforming materials have been tremendously improved. In this talk, we will briefly review the mathematical framework of the cofactor conditions and introduce an algorithmic way to evaluate these conditions directly from the X-ray measurements. We will also show some experimental results how the functional fatigue properties are enhanced at various length scales. 

 

Brief Biography of Prof. Xian(Sherry) Chen (HKUST)

Education:

Ph.D. and M.S., Aerospace Engineering and Mechanics, University of Minnesota, US

B.S., Materials Science and Engineering, Huazhong University of Science and Technology, China

 

Academic positions:

2015 – present, Assistant Professor, Mechanical and Aerospace Engineering, Hong Kong Univ. of Science and Technology, HK

2015 – 2016, Visiting Professor, Mechanical and Civil Engineering, California Institute of Technology, US

2014 – 2015, Postdoctoral Fellowship, Lawrence Berkeley National Lab, US

 

Research interests:

The research of our group integrates the theories of mechanics of crystalline solids with advanced structural characterization methods and algorithms to develop new phase-transforming materials. These materials have emerging applications in medical devices, microelectronics and energy conversion devices.

 

GRF grant (2016 – 2019): Investigation of microstructure-reversibility relationship for phase-transforming materials (Early Career Award)

GRF grant (2017 - 2020): Algorithmic approaches for high-throughput screen and discovery of new shape memory alloys

UGC grant (2017-2019): Measure 3D strain of phase transforming materials by Differential Interference Contrast optical system

Prof. Quandt

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Kolloquiumsvortrag (MAWI), Prof. Xian (Sherry) Chen, Hong Kong University of Science and Technology, / am 14.05.2018

14.05.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel:  Enhanced fatigue properties of phase-transforming materials by satisfying the cofactor conditions
 

Abstract:

Materials undergoing reversible solid-solid phase transformations provide emerging applications such as biomedical implants and stents, microelectronic actuators and sensors. The essential functionality of these materials is the ability to recover large deformation (i.e. 5~8%) before and after the structural transformation driven by temperature/stress/electromagnetic fields. The change of the lattice parameters and the breaking of symmetries, in turn, will cause the formation of microstructures, which lead to the accumulation of intrinsic defects at the stressed transition layer between phases.  It has been theorized that the macroscopic behaviors strongly depend on the kinematic properties of the transition layer between phases. If the lattice parameters satisfy some special mathematical conditions (the cofactor conditions), we observe that the functional fatigue properties of the phase-transforming materials have been tremendously improved. In this talk, we will briefly review the mathematical framework of the cofactor conditions and introduce an algorithmic way to evaluate these conditions directly from the X-ray measurements. We will also show some experimental results how the functional fatigue properties are enhanced at various length scales. 

 

Brief Biography of Prof. Xian(Sherry) Chen (HKUST)

Education:

Ph.D. and M.S., Aerospace Engineering and Mechanics, University of Minnesota, US

B.S., Materials Science and Engineering, Huazhong University of Science and Technology, China

 

Academic positions:

2015 – present, Assistant Professor, Mechanical and Aerospace Engineering, Hong Kong Univ. of Science and Technology, HK

2015 – 2016, Visiting Professor, Mechanical and Civil Engineering, California Institute of Technology, US

2014 – 2015, Postdoctoral Fellowship, Lawrence Berkeley National Lab, US

 

Research interests:

The research of our group integrates the theories of mechanics of crystalline solids with advanced structural characterization methods and algorithms to develop new phase-transforming materials. These materials have emerging applications in medical devices, microelectronics and energy conversion devices.

 

GRF grant (2016 – 2019): Investigation of microstructure-reversibility relationship for phase-transforming materials (Early Career Award)

GRF grant (2017 - 2020): Algorithmic approaches for high-throughput screen and discovery of new shape memory alloys

UGC grant (2017-2019): Measure 3D strain of phase transforming materials by Differential Interference Contrast optical system

Prof. Quandt

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Sonderkolloquium (ET/IT), Antrittsvorleseung, Prof. Dr. Andreas Bahr, Technische Fakultät der CAU am 26.04.2018

26.04.2018 von 17:00 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Brain Signal Acquisition with Miniaturized Electronic Systems for the Investigation of Local Neural Networks

Abstract:  In this talk, I will exemplify how advancements in the design of integrated sensor electronics enable new kinds of biomedical signal analysis:

In neuroscience research the development of the brain and the treatment of diseases like certain forms of epilepsy are analyzed with genetic mouse disease models. For the special case of the recording from neonatal mice (2-3 cm, 3-5 g) an implantable system has been developed, that enables chronic recordings. To achieve this, an application specific integrated circuit (ASIC) has been developed in an advanced 130 nm CMOS technology. Moreover, an implant and a recording system for live view of neural data have been presented. The functionality of the integrated circuit and the suitability of the implant system have been confirmed with in-vivo experiments with adult and 12 days old mice.

Andreas Bahr, Institute of Electrical Engineering and Information Technology, University of Kiel, Kiel, Germany, andreas.bahr@tf.uni-kiel.de

Prof. Bahr

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Sonderkolloquium (ET/IT), Antrittsvorleseung, Prof. Dr. Andreas Bahr, Technische Fakultät der CAU am 26.04.2018

26.04.2018 von 17:00 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Brain Signal Acquisition with Miniaturized Electronic Systems for the Investigation of Local Neural Networks

Abstract:  In this talk, I will exemplify how advancements in the design of integrated sensor electronics enable new kinds of biomedical signal analysis:

In neuroscience research the development of the brain and the treatment of diseases like certain forms of epilepsy are analyzed with genetic mouse disease models. For the special case of the recording from neonatal mice (2-3 cm, 3-5 g) an implantable system has been developed, that enables chronic recordings. To achieve this, an application specific integrated circuit (ASIC) has been developed in an advanced 130 nm CMOS technology. Moreover, an implant and a recording system for live view of neural data have been presented. The functionality of the integrated circuit and the suitability of the implant system have been confirmed with in-vivo experiments with adult and 12 days old mice.

Andreas Bahr, Institute of Electrical Engineering and Information Technology, University of Kiel, Kiel, Germany, andreas.bahr@tf.uni-kiel.de

Prof. Bahr

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Kolloquiumsvortrag, Dr. Sander-Thömmes, Physikalisch-Technische Bundesanstalt (PTB) in Berlin / am 23.04.2018

23.04.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Biomagnetic Sensing and Processing – Progress Using a Modular Approach

Abstract: In the field of biomagnetism the application of mathematical algorithms has been as important as the hardware itself. Traditionally, the hardware (the sensor Array) was based on superconducting quantum interference devices (SQUIDs) and operated for decades without large modifications. In contrast to that the range of relevant mathematical algorithms increased at a steady pace. This was driven by factors such as an ever increasing PC based computing power, new physiological insights motivating the application of existing algorithms, and the development of new algorithms to test biophysical models among others.

After around three decades of SQUID based Hardware, now new magnetic field sensors with the potential to replace or complement SQUIDs are available or under development. The opportunity for new sensors is the consequence of clinical challenges unsolved by state-of-the art SQUID based systems and due to new technology allowing alternative quantum physics based sensors in a small sized housing. These new sensors often have extra capabilities compared with SQUIDs and naturally some disadvantages. I will illustrate the modular approach using the example of optically pumped magnetometers and the signal processing toolbox FieldTrip.

Short biography

Tilmann Sander-Thömmes studied Physics at University of Freiburg and ETH Zürich and graduated there in 1992. He continued to obtain a PhD in solid-state physics at Imperial College in London. Following two post-docs in Berlin he has been working at Physikalisch-Technische Bundesanstalt since 2000 in the laboratory for Biosignals. Since 1998 he is involved with measuring and analysing magnetic brain signals. He is an expert in magnetoencephalography using both SQUIDs and more recently optically pumped magnetometers.

gus@tf.uni-kiel.de

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Kolloquiumsvortrag, Dr. Sander-Thömmes, Physikalisch-Technische Bundesanstalt (PTB) in Berlin / am 23.04.2018

23.04.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Biomagnetic Sensing and Processing – Progress Using a Modular Approach

Abstract: In the field of biomagnetism the application of mathematical algorithms has been as important as the hardware itself. Traditionally, the hardware (the sensor Array) was based on superconducting quantum interference devices (SQUIDs) and operated for decades without large modifications. In contrast to that the range of relevant mathematical algorithms increased at a steady pace. This was driven by factors such as an ever increasing PC based computing power, new physiological insights motivating the application of existing algorithms, and the development of new algorithms to test biophysical models among others.

After around three decades of SQUID based Hardware, now new magnetic field sensors with the potential to replace or complement SQUIDs are available or under development. The opportunity for new sensors is the consequence of clinical challenges unsolved by state-of-the art SQUID based systems and due to new technology allowing alternative quantum physics based sensors in a small sized housing. These new sensors often have extra capabilities compared with SQUIDs and naturally some disadvantages. I will illustrate the modular approach using the example of optically pumped magnetometers and the signal processing toolbox FieldTrip.

Short biography

Tilmann Sander-Thömmes studied Physics at University of Freiburg and ETH Zürich and graduated there in 1992. He continued to obtain a PhD in solid-state physics at Imperial College in London. Following two post-docs in Berlin he has been working at Physikalisch-Technische Bundesanstalt since 2000 in the laboratory for Biosignals. Since 1998 he is involved with measuring and analysing magnetic brain signals. He is an expert in magnetoencephalography using both SQUIDs and more recently optically pumped magnetometers.

gus@tf.uni-kiel.de

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Kolloquiumsvortrag, (ET/IT), Dr. Jan Abshagen, Wehrtechnische Dienststelle für Schiffe und Marinewaffen, Maritime Technologie und Forschung - WTD 71. / am 16.04.2018

16.04.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Flow-induced Noise in Hydroacoustic Sensor Systems

Abstract: Sound can propagate over a large distance in the sea without significant attenuation and is therefore of unique importance in underwater communication, navigation, and detection. Underwater sound is received in these applications with hydroacoustic sensor systems that are often attached to or towed behind a vessel. The turbulent flow that forms around the hull of the moving sensor system induces hydroacoustic noise in the interior that dominates the noise level (and therefore limits the performance) at larger speeds due to the strong speed dependence of flow acoustic sources (e.g. Lighthill’s v8-law). In a series of research cruises in recent years the statistical properties and underlying physical mechanisms of interior hydroacoustic noise induced from outer turbulent flows have been investigated under sea conditions with towed measurement systems. The talk will focus on the spatio-temporal correlation of the turbulent noise sources as well as the filter properties of the mechanical hull structure and the embedded hydrophones. The analysis is predominantly performed in wavenumber-frequency space. New developments in piezoelectric thin-film sensor technology allow in principle the design of specific wavenumber filters for flow noise reduction. The potential of such sensors for future underwater applications is discussed.

Prof. Schdmidt

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Kolloquiumsvortrag, (ET/IT), Dr. Jan Abshagen, Wehrtechnische Dienststelle für Schiffe und Marinewaffen, Maritime Technologie und Forschung - WTD 71. / am 16.04.2018

16.04.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Flow-induced Noise in Hydroacoustic Sensor Systems

Abstract: Sound can propagate over a large distance in the sea without significant attenuation and is therefore of unique importance in underwater communication, navigation, and detection. Underwater sound is received in these applications with hydroacoustic sensor systems that are often attached to or towed behind a vessel. The turbulent flow that forms around the hull of the moving sensor system induces hydroacoustic noise in the interior that dominates the noise level (and therefore limits the performance) at larger speeds due to the strong speed dependence of flow acoustic sources (e.g. Lighthill’s v8-law). In a series of research cruises in recent years the statistical properties and underlying physical mechanisms of interior hydroacoustic noise induced from outer turbulent flows have been investigated under sea conditions with towed measurement systems. The talk will focus on the spatio-temporal correlation of the turbulent noise sources as well as the filter properties of the mechanical hull structure and the embedded hydrophones. The analysis is predominantly performed in wavenumber-frequency space. New developments in piezoelectric thin-film sensor technology allow in principle the design of specific wavenumber filters for flow noise reduction. The potential of such sensors for future underwater applications is discussed.

Prof. Schdmidt

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Kolloquiumsvortrag (INF), Prof. Dr. Vijay Ganesh, University of Waterloo, Canada, am 13.04.2018

13.04.2018 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Thema: Modern SAT Solving in Practice

Abstract:

 

 

Dr. Vijay Ganesh is an assistant professor at the University of Waterloo since 2012. Prior to that he was a research scientist at MIT, and completed his PhD in computer science from Stanford University in 2007. Vijay's primary area of research is the theory and practice of automated reasoning aimed at software engineering, formal methods, security, and mathematics. In this context he has led the development of many SAT/SMT solvers, most notably, STP, The Z3 string solver, MapleSAT, andMathCheck. He has also proved several decidability and complexity results relating to the SATisfiability problem for various mathematical theories. For his research, he has won over 20 awards including an ACM Test of Time Award at CCS 2016, two Google Faculty Research Awards in 2011 and 2013, and a Ten-Year Most Influential Paper Award at DATE 2008.

Prof. Dr. Dirk Nowotka

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Kolloquiumsvortrag (INF), Prof. Dr. Vijay Ganesh, University of Waterloo, Canada, am 13.04.2018

13.04.2018 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Thema: Modern SAT Solving in Practice

Abstract:

 

 

Dr. Vijay Ganesh is an assistant professor at the University of Waterloo since 2012. Prior to that he was a research scientist at MIT, and completed his PhD in computer science from Stanford University in 2007. Vijay's primary area of research is the theory and practice of automated reasoning aimed at software engineering, formal methods, security, and mathematics. In this context he has led the development of many SAT/SMT solvers, most notably, STP, The Z3 string solver, MapleSAT, andMathCheck. He has also proved several decidability and complexity results relating to the SATisfiability problem for various mathematical theories. For his research, he has won over 20 awards including an ACM Test of Time Award at CCS 2016, two Google Faculty Research Awards in 2011 and 2013, and a Ten-Year Most Influential Paper Award at DATE 2008.

Prof. Dr. Dirk Nowotka

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Sonderkolloquiumsvortrag (ET&IT) Prof. Frank Vollmer, University of Exeter / am 12.04.2018

12.04.2018 von 14:00 bis 14:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Sensing the Nanoscale with Optoplasmonics

Abstract: Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. My laboratory is developing a new class of nanophotonic architectures by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. I will review our work in this burgeoning field of optoplasmonic biosensors. I will also talk about our most recent advances in localising light at the nanoscale in disordered 2D photonic crystals.

1Department of Physics and Astronomy, Living Systems Institute, University of Exeter, EX44QD, Exeter, UK

E-mail: f.vollmer@exeter.ac.uk

CV: Frank Vollmer is a Professor of Biophysics at the Living Systems Institute at the University of Exeter. Prof Vollmer pioneers optical technology to study processes at the nanoscale. He held several appointments at leading US institutions including Instructor in Medicine at Harvard Medical School. Before moving to the LSI in 2016, he held the position of Research Group Leader at the Max Planck Institute for the Science of Light (DE). In 2017 Prof Vollmer was awarded the Royal Society Wolfson Research Merit Award.

References

 

 

 

Prof. Gerken

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Sonderkolloquiumsvortrag (ET&IT) Prof. Frank Vollmer, University of Exeter / am 12.04.2018

12.04.2018 von 14:00 bis 14:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Sensing the Nanoscale with Optoplasmonics

Abstract: Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. My laboratory is developing a new class of nanophotonic architectures by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. I will review our work in this burgeoning field of optoplasmonic biosensors. I will also talk about our most recent advances in localising light at the nanoscale in disordered 2D photonic crystals.

1Department of Physics and Astronomy, Living Systems Institute, University of Exeter, EX44QD, Exeter, UK

E-mail: f.vollmer@exeter.ac.uk

CV: Frank Vollmer is a Professor of Biophysics at the Living Systems Institute at the University of Exeter. Prof Vollmer pioneers optical technology to study processes at the nanoscale. He held several appointments at leading US institutions including Instructor in Medicine at Harvard Medical School. Before moving to the LSI in 2016, he held the position of Research Group Leader at the Max Planck Institute for the Science of Light (DE). In 2017 Prof Vollmer was awarded the Royal Society Wolfson Research Merit Award.

References

 

 

 

Prof. Gerken

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Kolloquiumsvortrag (ETI/IT), Prof. Claus Hilgetag, UK Eppendorf, / am 09.04.2018

09.04.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel:  A simple excitable model reveals how brain network topology shapes neural activity patterns

Abstract: Brain networks are characterized by a number of distinctive topological features, such as a
heterogenous degree distribution with hubs, hierarchically organized modules, as well as a
characteristic spectrum of motifs and cycles. These features have consequences for various aspects
of brain dynamics, such as self‐sustained network activity, the wave‐like propagation of activations as
well as correlations and anti‐correlations of activity patterns. In a series of recent studies we have
demonstrated that the relation between neural network topology and dynamics can be
systematically investigated with the help of a simple, but powerful excitable (cellular automaton)
model which facilitates a mechanistic understanding of the contributions of different topological
features of brain networks to brain dynamics.

Prof. Kohlstedt

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Kolloquiumsvortrag (ETI/IT), Prof. Claus Hilgetag, UK Eppendorf, / am 09.04.2018

09.04.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel:  A simple excitable model reveals how brain network topology shapes neural activity patterns

Abstract: Brain networks are characterized by a number of distinctive topological features, such as a
heterogenous degree distribution with hubs, hierarchically organized modules, as well as a
characteristic spectrum of motifs and cycles. These features have consequences for various aspects
of brain dynamics, such as self‐sustained network activity, the wave‐like propagation of activations as
well as correlations and anti‐correlations of activity patterns. In a series of recent studies we have
demonstrated that the relation between neural network topology and dynamics can be
systematically investigated with the help of a simple, but powerful excitable (cellular automaton)
model which facilitates a mechanistic understanding of the contributions of different topological
features of brain networks to brain dynamics.

Prof. Kohlstedt

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Kolloquiumsvortrag (ET&IT), Dr. Timm Faulwasser, Karlsruhe Institute of Technology / am 12.02.2018

12.02.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Recent Progress on Distributed and Stochastic Optimization for Power Systems

Abstract: The increasing need for the de-carbonization of energy supply calls for new operational methods for power systems. In this context, tailored system and control approaches are pivotal- The specific challenges include the consideration of volatile renewable generation, uncertain forecasts thereof, and highly nonlinear system behavior.

In this talk, we focus on the so-called Optimal Power Flow (OPF) problem, which refers to a class of large-scale non-convex steady-state optimization problems frequently arising in power systems. For example, OPF problems provide optimal set points for power dispatch that satisfy the power flow equations and technical limitations such as generation and/or transmission limits. However, OPF problems are highly non-convex and subject to considerable uncertainties, which includes forecasts of renewable generation and household consumption, line parameters and grid topology.

After a concise problem statement, we provide an overview of the state of the art techniques to considering uncertainties in OPF problems and their bottlenecks. Moreover, we will discuss the concept of Polynomial Chaos Expansions (PCE) which allows to consider non-Gaussian uncertainties in OPF problems. PCE builds upon a series expansion of random-variables. We will present recent results on PCE for convex DC-OPF problems and non-convex AC-OPF problems [1, 2]. Moreover, we will comment on the quantification of PCE truncation errors [3].

Due to their large-scale nature, the distributed solution of OPF problems is subject to considerable research efforts. Thus, we will also comment on our recent results on the distributed solution of OPF problems [4].

References

[1] Mühlpfordt, T.; Faulwasser, T.; Roald, L. & Hagenmeyer, V. Solving optimal power flow with non-Gaussian uncertainties via polynomial chaos expansion. 56th IEEE Conference on Decision and Control, 2017. To appear.

[2] Mühlpfordt, T.; Faulwasser, T. & Hagenmeyer, V. Solving stochastic AC power flow via polynomial chaos expansion. IEEE International Conference on Control Applications, 2016, 70-76.

[3] Mühlpfordt, T.; Findeisen, R.; Hagenmeyer, V. & Faulwasser, T. Comments on Quantifying Truncation Errors for Polynomial Chaos Expansions. arXiv:1708.07655.

[4] Engelmann, A.; Mühlpfordt, T.; Jiang, Y.; Houska, B. & Faulwasser, T. Distributed AC optimal power flow using ALADIN. 20th IFAC World Congress, 2017.

Bio Sketch

Timm Faulwasser has studied Engineering Cybernetics at the University Stuttgart, with majors in systems and control and philosophy, where he graduated 2006. In 2007 he joined the group of Rolf Findeisen at the Institute of Automation Engineering at the Otto-von-Guericke University Magdeburg, Germany. From 2008-2012 he was a member of the International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering Magdeburg. In 2012 he obtained his PhD (with distinction) from Faculty of Electrical Engineering and Information Engineering, Otto-von-Guericke University Magdeburg, Germany. 2013-2016 he was with the Laboratoire d’Automatique, Ecole Polytechnique Fédérale de Lausanne, Switzerland. Since April 2015, he is with the Institute for Applied Informatics at the Karlsruhe Institute for Technology, where he leads the Optimization and Control Group.

His main research interests are optimization-based and predictive control of nonlinear systems with applications in energy systems, mechatronics/robotics, physics, process systems engineering and climate economics.

 

Prof. Meurer

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Kolloquiumsvortrag (ET&IT), Dr. Timm Faulwasser, Karlsruhe Institute of Technology / am 12.02.2018

12.02.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Recent Progress on Distributed and Stochastic Optimization for Power Systems

Abstract: The increasing need for the de-carbonization of energy supply calls for new operational methods for power systems. In this context, tailored system and control approaches are pivotal- The specific challenges include the consideration of volatile renewable generation, uncertain forecasts thereof, and highly nonlinear system behavior.

In this talk, we focus on the so-called Optimal Power Flow (OPF) problem, which refers to a class of large-scale non-convex steady-state optimization problems frequently arising in power systems. For example, OPF problems provide optimal set points for power dispatch that satisfy the power flow equations and technical limitations such as generation and/or transmission limits. However, OPF problems are highly non-convex and subject to considerable uncertainties, which includes forecasts of renewable generation and household consumption, line parameters and grid topology.

After a concise problem statement, we provide an overview of the state of the art techniques to considering uncertainties in OPF problems and their bottlenecks. Moreover, we will discuss the concept of Polynomial Chaos Expansions (PCE) which allows to consider non-Gaussian uncertainties in OPF problems. PCE builds upon a series expansion of random-variables. We will present recent results on PCE for convex DC-OPF problems and non-convex AC-OPF problems [1, 2]. Moreover, we will comment on the quantification of PCE truncation errors [3].

Due to their large-scale nature, the distributed solution of OPF problems is subject to considerable research efforts. Thus, we will also comment on our recent results on the distributed solution of OPF problems [4].

References

[1] Mühlpfordt, T.; Faulwasser, T.; Roald, L. & Hagenmeyer, V. Solving optimal power flow with non-Gaussian uncertainties via polynomial chaos expansion. 56th IEEE Conference on Decision and Control, 2017. To appear.

[2] Mühlpfordt, T.; Faulwasser, T. & Hagenmeyer, V. Solving stochastic AC power flow via polynomial chaos expansion. IEEE International Conference on Control Applications, 2016, 70-76.

[3] Mühlpfordt, T.; Findeisen, R.; Hagenmeyer, V. & Faulwasser, T. Comments on Quantifying Truncation Errors for Polynomial Chaos Expansions. arXiv:1708.07655.

[4] Engelmann, A.; Mühlpfordt, T.; Jiang, Y.; Houska, B. & Faulwasser, T. Distributed AC optimal power flow using ALADIN. 20th IFAC World Congress, 2017.

Bio Sketch

Timm Faulwasser has studied Engineering Cybernetics at the University Stuttgart, with majors in systems and control and philosophy, where he graduated 2006. In 2007 he joined the group of Rolf Findeisen at the Institute of Automation Engineering at the Otto-von-Guericke University Magdeburg, Germany. From 2008-2012 he was a member of the International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering Magdeburg. In 2012 he obtained his PhD (with distinction) from Faculty of Electrical Engineering and Information Engineering, Otto-von-Guericke University Magdeburg, Germany. 2013-2016 he was with the Laboratoire d’Automatique, Ecole Polytechnique Fédérale de Lausanne, Switzerland. Since April 2015, he is with the Institute for Applied Informatics at the Karlsruhe Institute for Technology, where he leads the Optimization and Control Group.

His main research interests are optimization-based and predictive control of nonlinear systems with applications in energy systems, mechatronics/robotics, physics, process systems engineering and climate economics.

 

Prof. Meurer

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Kolloquiumsvortrag (MaWi), Frau Dr. Berit Zeller-Plumdorf, Helmholtz Zentrum Geesthacht / am 05.02.2018

05.02.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Imaging and image-based modelling of biological and material systems

Abstract: Synchrotron radiation-based computed tomography (SRμCT) is a powerful tool for high-resolution imaging of materials. Whilst it traditionally depends on the X-ray attenuation by material components with high Z-numbers, it can be enhanced to enable imaging of biological soft tissues and other low-attenuation materials through propagation-based phase contrast. Due to the available high photon flux it is also possible to perform in situ testing, e.g. of material corrosion or mechanical loading experiments. In combination with image-based mathematical modelling, SRμCT enables the correlation between morphological and/or structural material measures and their function. In this presentation, showcases will be presented where SRμCT and image-based modelling have successfully been used to this end. These showcases include the assessment of osseointegration and in vitro degradation of biodegradable implants, the computational analysis of oxygenation in mouse muscle and the corrosion of steel embedded in concrete in aqueous solutions.

Prof. Willumeit-Römer

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Kolloquiumsvortrag (MaWi), Frau Dr. Berit Zeller-Plumdorf, Helmholtz Zentrum Geesthacht / am 05.02.2018

05.02.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Imaging and image-based modelling of biological and material systems

Abstract: Synchrotron radiation-based computed tomography (SRμCT) is a powerful tool for high-resolution imaging of materials. Whilst it traditionally depends on the X-ray attenuation by material components with high Z-numbers, it can be enhanced to enable imaging of biological soft tissues and other low-attenuation materials through propagation-based phase contrast. Due to the available high photon flux it is also possible to perform in situ testing, e.g. of material corrosion or mechanical loading experiments. In combination with image-based mathematical modelling, SRμCT enables the correlation between morphological and/or structural material measures and their function. In this presentation, showcases will be presented where SRμCT and image-based modelling have successfully been used to this end. These showcases include the assessment of osseointegration and in vitro degradation of biodegradable implants, the computational analysis of oxygenation in mouse muscle and the corrosion of steel embedded in concrete in aqueous solutions.

Prof. Willumeit-Römer

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Kolloquiumsvortrag (INF) Arindam Khan, TU München / am 02.02.2018

02.02.2018 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Approximating Geometric Knapsack via L-packings

Abstract: We study the two-dimensional geometric knapsack problem (2DK), a
geometric variant of the classical knapsack problem. In this problem, we
are given a set of axis-aligned rectangular items, each one with an
associated profit, and an axis-aligned square knapsack. The goal is to
find a (non-overlapping) packing of a maximum profit subset of items
inside the knapsack without rotating items. This is a very well-studied
optimization problem and finds applications in scheduling, memory
allocation, advertisement placement etc. The best-known polynomial-time
approximation factor for this problem (even just in the cardinality
case) is $2+\epsilon$ [Jansen and Zhang, SODA 2004].

After more than a decade, in this paper we break the 2-approximation
barrier, achieving a polynomial-time $17/9+\epsilon<1.89$ approximation,
which improves to $558/325+\epsilon<1.72$ in the cardinality case. We
also consider the variant of the problem with rotations (2DKR), where
the items can be rotated by $90$ degrees. Also, in this case, the
best-known polynomial-time approximation factor (even for the
cardinality case) is $2+\epsilon$ [Jansen and Zhang, SODA 2004].
Exploiting part of the machinery developed for 2DK plus a few additional
ideas, we obtain a polynomial-time $3/2+\epsilon$-approximation for
2DKR, which improves to $4/3+\epsilon$ in the cardinality case (joint
work with Waldo Galvez, Fabrizio Grandoni, Sandy Heydrich, Salvatore
Ingala and Andreas Wiese.).

Bio: Arindam Khan is a postdoc in Lehrstuhl für Theoretische Informatik
at Technische Universität München. His research areas include
approximation algorithms, online algorithms and computational geometry.
He has obtained his PhD in Algorithms, Combinatorics and Optimization
(ACO) from Georgia Institute of Technology, Atlanta, USA under Prof.
Prasad Tetali. Previously he has been a research intern in Theory group,
Microsoft Research Redmond and Microsoft Research Silicon Valley USA, a
visiting researcher at Simons Institute, Berkeley, USA; a blue scholar
in IBM Research India and a researcher at IDSIA, Lugano, Switzerland.

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Kolloquiumsvortrag (INF) Arindam Khan, TU München / am 02.02.2018

02.02.2018 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Approximating Geometric Knapsack via L-packings

Abstract: We study the two-dimensional geometric knapsack problem (2DK), a
geometric variant of the classical knapsack problem. In this problem, we
are given a set of axis-aligned rectangular items, each one with an
associated profit, and an axis-aligned square knapsack. The goal is to
find a (non-overlapping) packing of a maximum profit subset of items
inside the knapsack without rotating items. This is a very well-studied
optimization problem and finds applications in scheduling, memory
allocation, advertisement placement etc. The best-known polynomial-time
approximation factor for this problem (even just in the cardinality
case) is $2+\epsilon$ [Jansen and Zhang, SODA 2004].

After more than a decade, in this paper we break the 2-approximation
barrier, achieving a polynomial-time $17/9+\epsilon<1.89$ approximation,
which improves to $558/325+\epsilon<1.72$ in the cardinality case. We
also consider the variant of the problem with rotations (2DKR), where
the items can be rotated by $90$ degrees. Also, in this case, the
best-known polynomial-time approximation factor (even for the
cardinality case) is $2+\epsilon$ [Jansen and Zhang, SODA 2004].
Exploiting part of the machinery developed for 2DK plus a few additional
ideas, we obtain a polynomial-time $3/2+\epsilon$-approximation for
2DKR, which improves to $4/3+\epsilon$ in the cardinality case (joint
work with Waldo Galvez, Fabrizio Grandoni, Sandy Heydrich, Salvatore
Ingala and Andreas Wiese.).

Bio: Arindam Khan is a postdoc in Lehrstuhl für Theoretische Informatik
at Technische Universität München. His research areas include
approximation algorithms, online algorithms and computational geometry.
He has obtained his PhD in Algorithms, Combinatorics and Optimization
(ACO) from Georgia Institute of Technology, Atlanta, USA under Prof.
Prasad Tetali. Previously he has been a research intern in Theory group,
Microsoft Research Redmond and Microsoft Research Silicon Valley USA, a
visiting researcher at Simons Institute, Berkeley, USA; a blue scholar
in IBM Research India and a researcher at IDSIA, Lugano, Switzerland.

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Kolloquiumsvortrag (MaWi), Prof. Kläui, Uni Mainz / am 29.01.2018

29.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Topological Spin Dynamics for GreenIT

Abstract: In our information-everywhere society IT is a major player for energy consumption. Novel spintronic
devices can play a role in the quest for GreenIT if they are stable and can transport and manipulate
spin with low power. Devices have been proposed, where switching by energy-efficient approaches,
such as spin-polarized currents is used [1], for which we develop new highly spin-polarized materials
and characterize the spin transport using THz spectroscopy [2]. Firstly to obtain ultimate stability, topological spin structures that emerge due to the
Dzyaloshinskii-Moriya interaction (DMI) at structurally asymmetric interfaces, such as chiral domain
walls and skyrmions with enhanced topological protection can be used [3-5]. We have investigated in
detail their dynamics and find that it is governed by the topology of their spin structures [3]. By
designing the materials, we can even obtain a skyrmion lattice phase as the ground state of the thin
films [4]. Secondly, for ultimately efficient spin manipulation, we use spin-orbit torques, that can transfer
more than 1ħ per electron by transferring not only spin but also orbital angular momentum. We
combine ultimately stable skyrmions with spin orbit torques into a skyrmion racetrack device [4],
where the real time imaging of the trajectories allows us to quantify the novel skyrmion Hall effect
[5]. Finally to obtain efficient spin transport, we study graphene and low damping ferro- and
antiferromagnetic insulators as spin conduits for long distance spin transport [6] and explore the
superfluid spin current regime in antiferromagnets [7]. We find that we can control magnonic spin
currents by a newly developed magnon spin valve device [8].

[1] Reviews: O. Boulle et al., Mater. Sci. Eng. R 72, 159                                                                                                     
(2011); G. Finocchio et al., J. Phys. D: Appl. Phys. 49,
423001 (2016); A. Bisig et al., PRL 117, 277203 (2016)
[2] M. Jourdan et al., Nature Commun. 5, 3974 (2014);
Z. Jin et al., Nature Phys. 11, 761 (2015).
[3] F. Büttner et al., Nature Phys. 11, 225 (2015).
[4] S. Woo et al, Nature Mater. 15, 501 (2016).
[5] K. Litzius et al., Nature Phys. 13, 170 (2017).
[6] A. Kehlberger et al., Phys. Rev. Lett. 115, 096602 (2015);
S. Geprägs et al., Nature Commun. 7, 10452 (2016).
[7] Y. Tserkovnyak and M. Kläui, arxiv:1707.01082
[8] J. Cramer et al., arxiv:1706.07592

Kläui

Prof. McCord

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Kolloquiumsvortrag (MaWi), Prof. Kläui, Uni Mainz / am 29.01.2018

29.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Topological Spin Dynamics for GreenIT

Abstract: In our information-everywhere society IT is a major player for energy consumption. Novel spintronic
devices can play a role in the quest for GreenIT if they are stable and can transport and manipulate
spin with low power. Devices have been proposed, where switching by energy-efficient approaches,
such as spin-polarized currents is used [1], for which we develop new highly spin-polarized materials
and characterize the spin transport using THz spectroscopy [2]. Firstly to obtain ultimate stability, topological spin structures that emerge due to the
Dzyaloshinskii-Moriya interaction (DMI) at structurally asymmetric interfaces, such as chiral domain
walls and skyrmions with enhanced topological protection can be used [3-5]. We have investigated in
detail their dynamics and find that it is governed by the topology of their spin structures [3]. By
designing the materials, we can even obtain a skyrmion lattice phase as the ground state of the thin
films [4]. Secondly, for ultimately efficient spin manipulation, we use spin-orbit torques, that can transfer
more than 1ħ per electron by transferring not only spin but also orbital angular momentum. We
combine ultimately stable skyrmions with spin orbit torques into a skyrmion racetrack device [4],
where the real time imaging of the trajectories allows us to quantify the novel skyrmion Hall effect
[5]. Finally to obtain efficient spin transport, we study graphene and low damping ferro- and
antiferromagnetic insulators as spin conduits for long distance spin transport [6] and explore the
superfluid spin current regime in antiferromagnets [7]. We find that we can control magnonic spin
currents by a newly developed magnon spin valve device [8].

[1] Reviews: O. Boulle et al., Mater. Sci. Eng. R 72, 159                                                                                                     
(2011); G. Finocchio et al., J. Phys. D: Appl. Phys. 49,
423001 (2016); A. Bisig et al., PRL 117, 277203 (2016)
[2] M. Jourdan et al., Nature Commun. 5, 3974 (2014);
Z. Jin et al., Nature Phys. 11, 761 (2015).
[3] F. Büttner et al., Nature Phys. 11, 225 (2015).
[4] S. Woo et al, Nature Mater. 15, 501 (2016).
[5] K. Litzius et al., Nature Phys. 13, 170 (2017).
[6] A. Kehlberger et al., Phys. Rev. Lett. 115, 096602 (2015);
S. Geprägs et al., Nature Commun. 7, 10452 (2016).
[7] Y. Tserkovnyak and M. Kläui, arxiv:1707.01082
[8] J. Cramer et al., arxiv:1706.07592

Kläui

Prof. McCord

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Ferrimagnetic Tb-Fe based heterostructures: Intriguing properties and applications

Kolloquiumsvortrag (ET&IT), Prof. Martjin van den Heuvel, Brain Center Rudolf Magnu Utrecht / am 22.01.2018

22.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Exploring the human connectome

Abstract: Using network science as a general framework to study the network architecture of nervous system connectivity, more and more studies have highlighted the human and animal brain to display features of an efficient communication network. In my talk I will discuss potential general principles of wiring of connectome organization, principles conserved across species, and which may play an important role in general nervous system functioning. I will highlight findings that show connectomes to display cost-effective wiring, pronounced community structure, short communication relays, and the existence of richly connected 'hub regions'. I will discuss theories on how these themes of wiring may play a role in brain disorders, as well as establish a putative link between the micro- and macroscale organization of the human brain in health and disease.

Prof. Kohlstedt

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Kolloquiumsvortrag (ET&IT), Prof. Martjin van den Heuvel, Brain Center Rudolf Magnu Utrecht / am 22.01.2018

22.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Exploring the human connectome

Abstract: Using network science as a general framework to study the network architecture of nervous system connectivity, more and more studies have highlighted the human and animal brain to display features of an efficient communication network. In my talk I will discuss potential general principles of wiring of connectome organization, principles conserved across species, and which may play an important role in general nervous system functioning. I will highlight findings that show connectomes to display cost-effective wiring, pronounced community structure, short communication relays, and the existence of richly connected 'hub regions'. I will discuss theories on how these themes of wiring may play a role in brain disorders, as well as establish a putative link between the micro- and macroscale organization of the human brain in health and disease.

Prof. Kohlstedt

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Kolloquiumsvortrag (MaWi), Prof. Weller, Uni Hamburg / am 15.01.2018

15.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Nanocrystals in Materials and Life Science Applications

Abstract:

Horst Weller,
Institut für Physikalische Chemie, Universität Hamburg, Fraunhofer-Zentrum für Angewandte Nanotechnologie (CAN), The Hamburg Centre for Ultrafast Imaging (CUI)

Nanocrystals are already used for many applications in technical products for every day life. The talk will describe actual developments such as quantum dots in display and lighting technology and ultra-hard nanocomposite materials. Modern aspects of particle synthesis will be discussed.
The key idea for using nanocrystals for biomedical diagnostics is to benefit from their outstanding physical properties in the visualization of biological events or malignant cells or tissues. This requires a special design of the ligand shell, which preserves the fluorescent, magnetic and plasmonic properties of the particles in the biological environment on one side and allows a specific targeting on the other. The lecture reports on different chemical approaches and describes factors determining the biological response on fully synthetic nanocrystals. We will highlight concepts based on PEGylation and show how small deviations in the ligand shell alter the behavior in biological environment substantially. Moreover, we will present combinatorial approaches for the functionalization of the nanocrystals with biological affinity molecules to improve targeting specificity and concepts to optimize the physical properties of the inorganic core to increase the sensitivity for the respective imaging techniques.

Prof. Faupel

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Kolloquiumsvortrag (MaWi), Prof. Weller, Uni Hamburg / am 15.01.2018

15.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Nanocrystals in Materials and Life Science Applications

Abstract:

Horst Weller,
Institut für Physikalische Chemie, Universität Hamburg, Fraunhofer-Zentrum für Angewandte Nanotechnologie (CAN), The Hamburg Centre for Ultrafast Imaging (CUI)

Nanocrystals are already used for many applications in technical products for every day life. The talk will describe actual developments such as quantum dots in display and lighting technology and ultra-hard nanocomposite materials. Modern aspects of particle synthesis will be discussed.
The key idea for using nanocrystals for biomedical diagnostics is to benefit from their outstanding physical properties in the visualization of biological events or malignant cells or tissues. This requires a special design of the ligand shell, which preserves the fluorescent, magnetic and plasmonic properties of the particles in the biological environment on one side and allows a specific targeting on the other. The lecture reports on different chemical approaches and describes factors determining the biological response on fully synthetic nanocrystals. We will highlight concepts based on PEGylation and show how small deviations in the ligand shell alter the behavior in biological environment substantially. Moreover, we will present combinatorial approaches for the functionalization of the nanocrystals with biological affinity molecules to improve targeting specificity and concepts to optimize the physical properties of the inorganic core to increase the sensitivity for the respective imaging techniques.

Prof. Faupel

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Kolloquiumsvortrag (ET&IT) - muss leider entfallen - Prof. Frank Vollmer, University of Exeter / am 08.01.2018

08.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Sensing the Nanoscale with Optoplasmonics

Abstract: Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. My laboratory is developing a new class of nanophotonic architectures by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. I will review our work in this burgeoning field of optoplasmonic biosensors. I will also talk about our most recent advances in localising light at the nanoscale in disordered 2D photonic crystals.

1Department of Physics and Astronomy, Living Systems Institute, University of Exeter, EX44QD, Exeter, UK

E-mail: f.vollmer@exeter.ac.uk

CV: Frank Vollmer is a Professor of Biophysics at the Living Systems Institute at the University of Exeter. Prof Vollmer pioneers optical technology to study processes at the nanoscale. He held several appointments at leading US institutions including Instructor in Medicine at Harvard Medical School. Before moving to the LSI in 2016, he held the position of Research Group Leader at the Max Planck Institute for the Science of Light (DE). In 2017 Prof Vollmer was awarded the Royal Society Wolfson Research Merit Award.

References

 

 

 

 

Prof. Gerken

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Kolloquiumsvortrag (ET&IT) - muss leider entfallen - Prof. Frank Vollmer, University of Exeter / am 08.01.2018

08.01.2018 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Sensing the Nanoscale with Optoplasmonics

Abstract: Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. My laboratory is developing a new class of nanophotonic architectures by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. I will review our work in this burgeoning field of optoplasmonic biosensors. I will also talk about our most recent advances in localising light at the nanoscale in disordered 2D photonic crystals.

1Department of Physics and Astronomy, Living Systems Institute, University of Exeter, EX44QD, Exeter, UK

E-mail: f.vollmer@exeter.ac.uk

CV: Frank Vollmer is a Professor of Biophysics at the Living Systems Institute at the University of Exeter. Prof Vollmer pioneers optical technology to study processes at the nanoscale. He held several appointments at leading US institutions including Instructor in Medicine at Harvard Medical School. Before moving to the LSI in 2016, he held the position of Research Group Leader at the Max Planck Institute for the Science of Light (DE). In 2017 Prof Vollmer was awarded the Royal Society Wolfson Research Merit Award.

References

 

 

 

 

Prof. Gerken

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Kolloquiumsvortrag (MaWi), PD Dr. Pavel Levkin, Karlsruhe Institute of Technology / am 18.12.2017

18.12.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Designing biofunctional interfaces: from superhydrophobicity to cell microarrays

 

 

Abstract: Patterns of different surface properties are ubiquitous in nature and serve various important purposes. Desert beetles exploit superhydrophilic spots on their superhydrophobic back to collect water from the morning mist in the desert. Hydrophilic spots on a superhydrophobic surface of lichen plants allow them to uptake water, but also prevent the formation of water layers on the surface that could interfere with the discharge of lichen spores into the air. Superhydrophobic and omniphobic surfaces possess various unique properties including self-cleaning, liquid repellent and cell repellent properties. We are interested in creating precise two-dimensional micropatterns of apparently incompatible and opposite properties such as superhydrophobicity and superhydrophilicity or slippery and adhesive properties. To create such patterns we develop surface coatings with special wettabilities and photochemical surface functionalization strategies. Combining seemingly opposite properties in micropatterns leads to functionalities non-existent on the original homogeneous interfaces. For example, we showed that superhydrophobic-superhydrophilic patterned surfaces could be used to create patterns of cells, arrays of microdroplets suitable for high-throughput cell screenings, formation of arrays of hydrogel micropads or free-standing hydrogel particles with defined shapes for 3D cell culture. Patterned liquid-infused interfaces could be also used to form cell microarrays or arrays of isolated biofilm colonies for biofilm screenings.

Bild

Prof. Selhuber

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Kolloquiumsvortrag (MaWi), PD Dr. Pavel Levkin, Karlsruhe Institute of Technology / am 18.12.2017

18.12.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Designing biofunctional interfaces: from superhydrophobicity to cell microarrays

 

 

Abstract: Patterns of different surface properties are ubiquitous in nature and serve various important purposes. Desert beetles exploit superhydrophilic spots on their superhydrophobic back to collect water from the morning mist in the desert. Hydrophilic spots on a superhydrophobic surface of lichen plants allow them to uptake water, but also prevent the formation of water layers on the surface that could interfere with the discharge of lichen spores into the air. Superhydrophobic and omniphobic surfaces possess various unique properties including self-cleaning, liquid repellent and cell repellent properties. We are interested in creating precise two-dimensional micropatterns of apparently incompatible and opposite properties such as superhydrophobicity and superhydrophilicity or slippery and adhesive properties. To create such patterns we develop surface coatings with special wettabilities and photochemical surface functionalization strategies. Combining seemingly opposite properties in micropatterns leads to functionalities non-existent on the original homogeneous interfaces. For example, we showed that superhydrophobic-superhydrophilic patterned surfaces could be used to create patterns of cells, arrays of microdroplets suitable for high-throughput cell screenings, formation of arrays of hydrogel micropads or free-standing hydrogel particles with defined shapes for 3D cell culture. Patterned liquid-infused interfaces could be also used to form cell microarrays or arrays of isolated biofilm colonies for biofilm screenings.

Bild

Prof. Selhuber

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Kolloquiumsvortrag, Dr. Patrick Totzke / Laboratory for Foundations of Computer Science at Edinburgh/ am 15.12.2017

15.12.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Combined Objectives in Simple Stochastic Games

Abstract: SSG are turn-based, perfect information games where states are controlled by Adam, Eve or a randomized environment. The two opposing players compete to maximize/minimize the probability of a given winning condition (the objective of the game). I will outline a line of research that considers combinations of objectives classically studied for the verification of reactive systems, such as Parity, Mean-Payoff or limit-reward criteria. The aim is to determine under which conditions, to what extend, and with how much extra effort a player can achieve multiple objectives simultaneously. Time permitting, I will outline a recent result that exposes a subtle bug in the literature and shows how to fix it.

Prof. Nowotka

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Kolloquiumsvortrag, Dr. Patrick Totzke / Laboratory for Foundations of Computer Science at Edinburgh/ am 15.12.2017

15.12.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Combined Objectives in Simple Stochastic Games

Abstract: SSG are turn-based, perfect information games where states are controlled by Adam, Eve or a randomized environment. The two opposing players compete to maximize/minimize the probability of a given winning condition (the objective of the game). I will outline a line of research that considers combinations of objectives classically studied for the verification of reactive systems, such as Parity, Mean-Payoff or limit-reward criteria. The aim is to determine under which conditions, to what extend, and with how much extra effort a player can achieve multiple objectives simultaneously. Time permitting, I will outline a recent result that exposes a subtle bug in the literature and shows how to fix it.

Prof. Nowotka

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Kolloquiumsvortrag (MaWi), Prof. Friedrich Frischknecht, Universität Heidelberg / am 11.12.2017

11.12.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Malaria transmission: new insights from in vivo imaging and materials science

Abstract: Malaria parasites are transmitted by mosquitoes and multiply to large numbers in red blood cells to cause disease. When taken up by mosquitoes the parasite develop in large cysts in their guts from where they emerge to colonize the salivary glands of the insect. From there the parasites are injected into the skin where they have to migrate to find a blood vessel. After entering the blood vessel the parasites first enter liver cells where they multiply without causing disease symptoms. In this seminar I will illuminate some of this curious biology using a set of different microscopy techniques, molecular genetics and biophysical approaches. We will see how parasites form within the cysts, how they leave the cysts, move within salivary glands and in the skin. Using laser tweezers we have measured the force they can produce and using micro-pillar arrays we have asked whether they adapted their shape in order to find the small blood capillaries into which they enter. For more info see: www.sporozoite.org

Prof. Selhuber

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Kolloquiumsvortrag (MaWi), Prof. Friedrich Frischknecht, Universität Heidelberg / am 11.12.2017

11.12.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Malaria transmission: new insights from in vivo imaging and materials science

Abstract: Malaria parasites are transmitted by mosquitoes and multiply to large numbers in red blood cells to cause disease. When taken up by mosquitoes the parasite develop in large cysts in their guts from where they emerge to colonize the salivary glands of the insect. From there the parasites are injected into the skin where they have to migrate to find a blood vessel. After entering the blood vessel the parasites first enter liver cells where they multiply without causing disease symptoms. In this seminar I will illuminate some of this curious biology using a set of different microscopy techniques, molecular genetics and biophysical approaches. We will see how parasites form within the cysts, how they leave the cysts, move within salivary glands and in the skin. Using laser tweezers we have measured the force they can produce and using micro-pillar arrays we have asked whether they adapted their shape in order to find the small blood capillaries into which they enter. For more info see: www.sporozoite.org

Prof. Selhuber

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Kolloquiumsvortrag (ET&IT), Dr. Andreas Bisplinghoff, Cisco / am 04.12.2017

04.12.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: From Long-Haul to Data-Center-Interconnect - Effiziente Signalverarbeitungsalgorithmen für Flexible Optische Netze

Abstract: First coherent optical communication systems, operating at 40Gbps, have been deployed in 2005. Since then, coherent optical technology has undergone remarkable development in the most recent years. Nowadays, state of the art products support line rates up to 400Gbps per wavelength. Next generation systems will primarily target for higher integration density but will presumably also reach line rates of 600Gbps and beyond.

With progress both in CMOS technology and of optical components, coherent optical transmission continuously pushes forward to highest reach for ultra-long haul applications as well as to highest capacity for shorter reach data-center interconnects. Both directions involve very specific requirements both on the capabilities of applied DSP algorithms and integration density of electrical and optical components.

Each new CMOS technology node facilitates the implementation of more sophisticated DSP algorithms. Many DSP components have undergone tremendous development during the most recent years, enabling coherent systems operating at highest transmission rates. Very efficient equalizer algorithms compensate for linear (CD, PMD) and non-linear (SPM, XPM) signal distortions, enhanced soft-decoded forward error correction schemes improve the noise tolerance, and with probabilistic constellation shaping performance will ultimately approach the Shannon limit.

This talk gives a high-level overview about state of the art DSP algorithms and most recent developments in coherent optical communication. It then discusses the balancing act to address the specific requirements of highest reach as well as highest capacity transmission within a single ASIC. Finally, some selected tradeoffs in algorithm and architecture optimization are shown by means of soft-decoded forward error correction as an example.

Bio: Andreas Bisplinghoff was born in Forchheim in 1984. He received the Dipl.-Ing. and Dr.-Ing. degrees both in electrical and electronic engineering from the Friedrich-Alexander University of Erlangen in 2009 and 2015, respectively.

From 2010 to 2013, he was a Research Assistant with the Institute of Microwaves and Photonics at the University of Erlangen. Since 2013 he has been a Hardware Engineer in Advanced Development with the Cisco Optical GmbH. His research interests include the development of slip-reduced carrier phase recovery techniques and of power-efficient forward error correction schemes for coherent optical communication. Andreas Bisplinghoff has broad experience in complexity-aware algorithm design, FPGA-based prototyping, and power-optimized ASIC implementation.

 

 

Prof. Pachnicke

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Kolloquiumsvortrag (ET&IT), Dr. Andreas Bisplinghoff, Cisco / am 04.12.2017

04.12.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: From Long-Haul to Data-Center-Interconnect - Effiziente Signalverarbeitungsalgorithmen für Flexible Optische Netze

Abstract: First coherent optical communication systems, operating at 40Gbps, have been deployed in 2005. Since then, coherent optical technology has undergone remarkable development in the most recent years. Nowadays, state of the art products support line rates up to 400Gbps per wavelength. Next generation systems will primarily target for higher integration density but will presumably also reach line rates of 600Gbps and beyond.

With progress both in CMOS technology and of optical components, coherent optical transmission continuously pushes forward to highest reach for ultra-long haul applications as well as to highest capacity for shorter reach data-center interconnects. Both directions involve very specific requirements both on the capabilities of applied DSP algorithms and integration density of electrical and optical components.

Each new CMOS technology node facilitates the implementation of more sophisticated DSP algorithms. Many DSP components have undergone tremendous development during the most recent years, enabling coherent systems operating at highest transmission rates. Very efficient equalizer algorithms compensate for linear (CD, PMD) and non-linear (SPM, XPM) signal distortions, enhanced soft-decoded forward error correction schemes improve the noise tolerance, and with probabilistic constellation shaping performance will ultimately approach the Shannon limit.

This talk gives a high-level overview about state of the art DSP algorithms and most recent developments in coherent optical communication. It then discusses the balancing act to address the specific requirements of highest reach as well as highest capacity transmission within a single ASIC. Finally, some selected tradeoffs in algorithm and architecture optimization are shown by means of soft-decoded forward error correction as an example.

Bio: Andreas Bisplinghoff was born in Forchheim in 1984. He received the Dipl.-Ing. and Dr.-Ing. degrees both in electrical and electronic engineering from the Friedrich-Alexander University of Erlangen in 2009 and 2015, respectively.

From 2010 to 2013, he was a Research Assistant with the Institute of Microwaves and Photonics at the University of Erlangen. Since 2013 he has been a Hardware Engineer in Advanced Development with the Cisco Optical GmbH. His research interests include the development of slip-reduced carrier phase recovery techniques and of power-efficient forward error correction schemes for coherent optical communication. Andreas Bisplinghoff has broad experience in complexity-aware algorithm design, FPGA-based prototyping, and power-optimized ASIC implementation.

 

 

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Kolloquiumsvortrag (ET&IT), Dr.-Ing. Vasudev Kanade Rajan / am 27.11.2017

27.11.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Digital Road Noise Cancellation System Through Active Noise Control

Abstract: The application of active noise cancellation in real-world has not been fully realized yet. From reducing environment noise through the usage of headphones, to engine noise on commercial jets there are a number of use cases. Each of these use case brings its own set of challenges which can be understood only through multi-disciplinary work. One such use case the the reduction of road noise in vehicles. Structure-borne road noise dominates the cabin of modern vehicles. Several road noise cancellation (RNC) prototype systems have been implemented and demonstrated. These systems are based mainly on analog sensors. The placement of these sensors has been so far been based on random optimization methods. In this talk I will talk about the challenges in developing a generic digital RNC system which includes problem analysis, sensor placement, and performance. An adaptive algorithm process the acceleration signals with high convergence and reaction time for various speed and surface ranges, in order to maintain high audible effects for the passengers. Several modern vehicle platforms are integrated with the digital RNC system with ANC microphone at the headliners and the standard audio loudspeaker setup in order to integrate the technology with the existing audio layout of the vehicle.

Short biography

Vasudev Kandade Rajan received Bachelors degree in Electronics and Communication from Visvesvaraya Technological University, Bangalore, India. He joined as Project Research Assistant in July 2008 in the Electrical Communication Engineering Dept, Indian Institute of Science, Bangalore. There he worked on performance management of IEEE 802.11 WLANs until Sept 2009. He then went to obtain his Masters degree (MSc.) in Digital Communications, 2011 and PhD degree in Signal Processing, 2017 from Universtiy of Kiel, Germany. Currently he is working in the R&D department of Harman Becker Automotive Systems GmbH, Straubing, Germany.

Prof. Schmidt

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Kolloquiumsvortrag (ET&IT), Dr.-Ing. Vasudev Kanade Rajan / am 27.11.2017

27.11.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Digital Road Noise Cancellation System Through Active Noise Control

Abstract: The application of active noise cancellation in real-world has not been fully realized yet. From reducing environment noise through the usage of headphones, to engine noise on commercial jets there are a number of use cases. Each of these use case brings its own set of challenges which can be understood only through multi-disciplinary work. One such use case the the reduction of road noise in vehicles. Structure-borne road noise dominates the cabin of modern vehicles. Several road noise cancellation (RNC) prototype systems have been implemented and demonstrated. These systems are based mainly on analog sensors. The placement of these sensors has been so far been based on random optimization methods. In this talk I will talk about the challenges in developing a generic digital RNC system which includes problem analysis, sensor placement, and performance. An adaptive algorithm process the acceleration signals with high convergence and reaction time for various speed and surface ranges, in order to maintain high audible effects for the passengers. Several modern vehicle platforms are integrated with the digital RNC system with ANC microphone at the headliners and the standard audio loudspeaker setup in order to integrate the technology with the existing audio layout of the vehicle.

Short biography

Vasudev Kandade Rajan received Bachelors degree in Electronics and Communication from Visvesvaraya Technological University, Bangalore, India. He joined as Project Research Assistant in July 2008 in the Electrical Communication Engineering Dept, Indian Institute of Science, Bangalore. There he worked on performance management of IEEE 802.11 WLANs until Sept 2009. He then went to obtain his Masters degree (MSc.) in Digital Communications, 2011 and PhD degree in Signal Processing, 2017 from Universtiy of Kiel, Germany. Currently he is working in the R&D department of Harman Becker Automotive Systems GmbH, Straubing, Germany.

Prof. Schmidt

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Kolloquiumsvortrag (ET&IT), M.Sc. Jonas Sauter, Nuance Communications / am 20.11.2017

20.11.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Artificial Bandwidth Extension for Speech Signals Using Deep Neural Networks

Abstract: In mobile communication, the bandwidth of transferred speech signals is either narrow-band (300Hz – 3.4kHz) or wide-band (50Hz – 7kHz or higher). As the limitation to 3.4kHz degrades the speech quality and intelligibility, it is of great interest to artificially extend narrow-band speech signals to wide-band speech.

This talk presents a deep neural network (DNN) approach to artificial bandwidth extension with a focus on robustness in practical applications.

It is based on the source-filter model which decomposes the signal into two parts: an excitation signal and a spectral envelope. The excitation (source part) describes the fine spectral structure which consists of white noise for unvoiced speech and an impulse train for voiced speech. The spectral envelope (filter part) describes the coarse spectral structure, i.e. the formants or resonance frequencies that make up different phonemes.

While the extension of the excitation signal can be done with simple mathematical methods that do not introduce strong artifacts, the envelope is much more relevant for the quality of the reconstructed wide-band signal. That is why the wide-band envelope is estimated with DNNs in this approach, which are trained on a large speech corpus.

Short biography

Jonas Sautter studied Electrical Engineering, Information Technology and Computer Engineering at RWTH Aachen University, Germany. He received his Master of Science degree in 2016. The Master’s thesis with the title “Digital Robust Control for Active Noise Cancellation in Headphones and Hearing Aids” was composed at the Institute of Communication Systems at RWTH Aachen. Since November 2016, he is a PhD student at Nuance Communications in Ulm, supervised by Professor Gerhard Schmidt, Head of the Digital Signal Processing and System Theory group at Christian-Albrechts-Universität, Kiel.

Prof. Schmidt

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Kolloquiumsvortrag (ET&IT), M.Sc. Jonas Sauter, Nuance Communications / am 20.11.2017

20.11.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Artificial Bandwidth Extension for Speech Signals Using Deep Neural Networks

Abstract: In mobile communication, the bandwidth of transferred speech signals is either narrow-band (300Hz – 3.4kHz) or wide-band (50Hz – 7kHz or higher). As the limitation to 3.4kHz degrades the speech quality and intelligibility, it is of great interest to artificially extend narrow-band speech signals to wide-band speech.

This talk presents a deep neural network (DNN) approach to artificial bandwidth extension with a focus on robustness in practical applications.

It is based on the source-filter model which decomposes the signal into two parts: an excitation signal and a spectral envelope. The excitation (source part) describes the fine spectral structure which consists of white noise for unvoiced speech and an impulse train for voiced speech. The spectral envelope (filter part) describes the coarse spectral structure, i.e. the formants or resonance frequencies that make up different phonemes.

While the extension of the excitation signal can be done with simple mathematical methods that do not introduce strong artifacts, the envelope is much more relevant for the quality of the reconstructed wide-band signal. That is why the wide-band envelope is estimated with DNNs in this approach, which are trained on a large speech corpus.

Short biography

Jonas Sautter studied Electrical Engineering, Information Technology and Computer Engineering at RWTH Aachen University, Germany. He received his Master of Science degree in 2016. The Master’s thesis with the title “Digital Robust Control for Active Noise Cancellation in Headphones and Hearing Aids” was composed at the Institute of Communication Systems at RWTH Aachen. Since November 2016, he is a PhD student at Nuance Communications in Ulm, supervised by Professor Gerhard Schmidt, Head of the Digital Signal Processing and System Theory group at Christian-Albrechts-Universität, Kiel.

Prof. Schmidt

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Kolloquiumsvortrag (ET&IT), Prof. Elisabetta Chicca, Uni Bielefeld / am 13.11.2017

13.11.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Learning in silico beyond STDP

Abstract: Synaptic plasticity empowers biological nervous systems with the ability to learn from experience and adjust to environmental changes. Such abilities are a must for artificial autonomous systems and therefore researchers have been devoting significant efforts to the understanding and modelling of plasticity mechanisms. In particular, the field of neuromorphic engineering focuses on the development of full-custom hybrid analog/digital electronic systems for the implementation of models of biological computation and learning in hardware. I will give a short historical overview of the most important plasticity circuits developed following the approach originally proposed by Carver Mead in the late eighties. Afterwards, I will present recent advancements in this field.

PD Martin Ziegler

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Kolloquiumsvortrag (ET&IT), Prof. Elisabetta Chicca, Uni Bielefeld / am 13.11.2017

13.11.2017 von 17:15 bis 18:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Learning in silico beyond STDP

Abstract: Synaptic plasticity empowers biological nervous systems with the ability to learn from experience and adjust to environmental changes. Such abilities are a must for artificial autonomous systems and therefore researchers have been devoting significant efforts to the understanding and modelling of plasticity mechanisms. In particular, the field of neuromorphic engineering focuses on the development of full-custom hybrid analog/digital electronic systems for the implementation of models of biological computation and learning in hardware. I will give a short historical overview of the most important plasticity circuits developed following the approach originally proposed by Carver Mead in the late eighties. Afterwards, I will present recent advancements in this field.

PD Martin Ziegler

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Sonderkolloquium (INF), Vijay Ganesh, University of Waterloo, Kanada / am 17.10.2017

17.10.2017 von 14:00 bis 15:00

Institut für Informatik, Christian-Albrechts-Platz 4, 24118 Kiel

Titel: On The Unreasonable Effectiveness of Boolean SAT Solvers

Abstract: Modern conflict-driven clause-learning (CDCL) Boolean SAT solvers routinely solve very large industrial SAT instances in relatively short periods of time. This phenomenon has stumped both theoreticians and practitioners since Boolean satisfiability is an NP-complete problem widely believed to be intractable. It is clear that these solvers somehow exploit the structure of real-world instances. However, to-date there have been few results that precisely characterize this structure or shed any light on why these SAT solvers are so efficient.

In this talk, I will present results that provide a deeper empirical understanding of why CDCL SAT solvers are so efficient, which may eventually lead to a complexity-theoretic result. Our results can be divided into two parts. First, I will talk about structural parameters that can characterize industrial instances and shed light on why they are easier to solve even though they may contain millions of variables compared to small crafted instances with hundreds of variables. Second, I will talk about internals of CDCL SAT solvers, and describe why they are particularly suited to solve industrial instances.

Brief Bio: Dr. Vijay Ganesh is an assistant professor at the University of Waterloo since 2012. Prior to that he was a research scientist at MIT, and completed his PhD in computer science from Stanford University in 2007. Vijay's primary area of research is the theory and practice of automated reasoning aimed at software engineering, formal methods, security, and mathematics. In this context he has led the development of many SAT/SMT solvers, most notably, STP, The Z3 string solver, MapleSAT, and MathCheck. He has also proved several decidability and complexity results relating to the SATisfiability problem for various mathematical theories. For his research, he has won over 20 awards including an ACM Test of Time Award at CCS 2016, two Google Faculty Research Awards in 2011 and 2013, and a Ten-Year Most Influential Paper Award at DATE 2008.

Prof. Nowotka

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Sonderkolloquium (INF), Vijay Ganesh, University of Waterloo, Kanada / am 17.10.2017

17.10.2017 von 14:00 bis 15:00

Institut für Informatik, Christian-Albrechts-Platz 4, 24118 Kiel

Titel: On The Unreasonable Effectiveness of Boolean SAT Solvers

Abstract: Modern conflict-driven clause-learning (CDCL) Boolean SAT solvers routinely solve very large industrial SAT instances in relatively short periods of time. This phenomenon has stumped both theoreticians and practitioners since Boolean satisfiability is an NP-complete problem widely believed to be intractable. It is clear that these solvers somehow exploit the structure of real-world instances. However, to-date there have been few results that precisely characterize this structure or shed any light on why these SAT solvers are so efficient.

In this talk, I will present results that provide a deeper empirical understanding of why CDCL SAT solvers are so efficient, which may eventually lead to a complexity-theoretic result. Our results can be divided into two parts. First, I will talk about structural parameters that can characterize industrial instances and shed light on why they are easier to solve even though they may contain millions of variables compared to small crafted instances with hundreds of variables. Second, I will talk about internals of CDCL SAT solvers, and describe why they are particularly suited to solve industrial instances.

Brief Bio: Dr. Vijay Ganesh is an assistant professor at the University of Waterloo since 2012. Prior to that he was a research scientist at MIT, and completed his PhD in computer science from Stanford University in 2007. Vijay's primary area of research is the theory and practice of automated reasoning aimed at software engineering, formal methods, security, and mathematics. In this context he has led the development of many SAT/SMT solvers, most notably, STP, The Z3 string solver, MapleSAT, and MathCheck. He has also proved several decidability and complexity results relating to the SATisfiability problem for various mathematical theories. For his research, he has won over 20 awards including an ACM Test of Time Award at CCS 2016, two Google Faculty Research Awards in 2011 and 2013, and a Ten-Year Most Influential Paper Award at DATE 2008.

Prof. Nowotka

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Kolloquiumsvortrag, Prof. Dr. Stefan Sauter, Uni Zürich / am 21.07.2017

21.07.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: A Family of Crouzeix-Raviart Non-Conforming Finite Elements in Two- and Three Spatial Dimensions

Abstract: In this talk we will present a family of non-conforming "Crouzeix-Raviart" type finite elements in two and three dimensions. They consist of local polynomials of maximal degree p on simplicial finite element meshes while certain jump conditions are imposed across adjacent simplices.

We will prove optimal a priori estimates for these finite elements. The characterization of this space via jump conditions goes back to the seminal paper of Crouzeix and Raviart in 1973. However, the definition is implicit and the derivation of an explicit representation of the local basis functions for general p in 3D was an open problem.

We present explicit representations for these functions by developing some theoretical tools for fully symmetric and reflection symmetric orthogonal polynomials on triangles and their representation.

Finally we will analyze the linear independence of these sets of functions and discuss the question whether they span the whole non-conforming space. This talk comprises joint work with P. Ciarlet Jr., ENSTA, Paris and Charles F. Dunkl, Virginia Tech.

Prof. Börm

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Kolloquiumsvortrag, Prof. Dr. Stefan Sauter, Uni Zürich / am 21.07.2017

21.07.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: A Family of Crouzeix-Raviart Non-Conforming Finite Elements in Two- and Three Spatial Dimensions

Abstract: In this talk we will present a family of non-conforming "Crouzeix-Raviart" type finite elements in two and three dimensions. They consist of local polynomials of maximal degree p on simplicial finite element meshes while certain jump conditions are imposed across adjacent simplices.

We will prove optimal a priori estimates for these finite elements. The characterization of this space via jump conditions goes back to the seminal paper of Crouzeix and Raviart in 1973. However, the definition is implicit and the derivation of an explicit representation of the local basis functions for general p in 3D was an open problem.

We present explicit representations for these functions by developing some theoretical tools for fully symmetric and reflection symmetric orthogonal polynomials on triangles and their representation.

Finally we will analyze the linear independence of these sets of functions and discuss the question whether they span the whole non-conforming space. This talk comprises joint work with P. Ciarlet Jr., ENSTA, Paris and Charles F. Dunkl, Virginia Tech.

Prof. Börm

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Sonderkolloquium, Prof. Dr. María López Fernández, Universität Zürich / am 18.07.2017

18.07.2017 von 11:00 bis 13:00

Ludewig-Meyn-Str. 2. Raum Ü2/K (LMS2, R. Ü2/K), 24118 Kiel

Titel: Generalized Convolution Quadrature

Abstract: ubich's Convolution Quadrature is nowadays a well
established method for the time discretization of retarded potentials
associated to wave equations. It has been very much developed in the
last decade, both from the theoretical and the algorithmic point of
view. However, despite its nice properties, the Convolution Quadrature
is strictly restricted to the use of fixed time steps. In this talk I
will present the "generalized Convolution Quadrature", a new family of
methods designed to overcome the strong restriction to uniform
temporal grids. I will show stability and convergence estimates and
numerical results illustrating the good behaviour of the new method. I
will also outline the current limitations in the implementation of the
generalized Convolution Quadrature and future possibilities of
development.

Prof. Börm

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Sonderkolloquium, Prof. Dr. María López Fernández, Universität Zürich / am 18.07.2017

18.07.2017 von 11:00 bis 13:00

Ludewig-Meyn-Str. 2. Raum Ü2/K (LMS2, R. Ü2/K), 24118 Kiel

Titel: Generalized Convolution Quadrature

Abstract: ubich's Convolution Quadrature is nowadays a well
established method for the time discretization of retarded potentials
associated to wave equations. It has been very much developed in the
last decade, both from the theoretical and the algorithmic point of
view. However, despite its nice properties, the Convolution Quadrature
is strictly restricted to the use of fixed time steps. In this talk I
will present the "generalized Convolution Quadrature", a new family of
methods designed to overcome the strong restriction to uniform
temporal grids. I will show stability and convergence estimates and
numerical results illustrating the good behaviour of the new method. I
will also outline the current limitations in the implementation of the
generalized Convolution Quadrature and future possibilities of
development.

Prof. Börm

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Sonderkolloquium, Tomislav Dragicevic, University Aalborg / 12.07.2017

12.07.2017 von 15:00 bis 16:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Coordination Strategies for DC Microgrids

Abstract: DC distribution systems have higher efficiency, better current carrying capacity and faster response when compared to conventional AC systems. They also provide more natural interface with many types of RES and ESSs and better compliance with consumer electronics. Furthermore, when components are coupled around a DC bus, there are no issues with reactive power flow, power quality and frequency regulation, resulting in a notably less complex control system when compared to the AC coupled systems. All these facts lead to more and more applications of DC systems in modern power systems, including data/telecom centers, maritime industry, high voltage transmission systems, electric vehicle charging infrastructure, and DC microgrids. Still, design and operation of general DC systems imposes a number of specific challenges. The aim of this lecture is in particular to present functionalities of different coordinated control strategies for DC microgrids. In this context, centralized, decentralized and distributed controls are assessed. Decentralized control can be regarded as an extension of local control since it is also based exclusively on local measurements. In contrast, centralized and distributed control strategies rely on digital communication technologies. A number of approaches of using these three coordinated control strategies to achieve various control objectives are reviewed in the paper. Moreover, properties of DC MG dynamics and stability are discussed.

Prof. Liserre

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Sonderkolloquium, Tomislav Dragicevic, University Aalborg / 12.07.2017

12.07.2017 von 15:00 bis 16:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Coordination Strategies for DC Microgrids

Abstract: DC distribution systems have higher efficiency, better current carrying capacity and faster response when compared to conventional AC systems. They also provide more natural interface with many types of RES and ESSs and better compliance with consumer electronics. Furthermore, when components are coupled around a DC bus, there are no issues with reactive power flow, power quality and frequency regulation, resulting in a notably less complex control system when compared to the AC coupled systems. All these facts lead to more and more applications of DC systems in modern power systems, including data/telecom centers, maritime industry, high voltage transmission systems, electric vehicle charging infrastructure, and DC microgrids. Still, design and operation of general DC systems imposes a number of specific challenges. The aim of this lecture is in particular to present functionalities of different coordinated control strategies for DC microgrids. In this context, centralized, decentralized and distributed controls are assessed. Decentralized control can be regarded as an extension of local control since it is also based exclusively on local measurements. In contrast, centralized and distributed control strategies rely on digital communication technologies. A number of approaches of using these three coordinated control strategies to achieve various control objectives are reviewed in the paper. Moreover, properties of DC MG dynamics and stability are discussed.

Prof. Liserre

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Kolloquiumsvortrag, Prof. Grandoni, IDSIA USI-SUPSI in Lugano / am 07.07.2017

07.07.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, Raum Ü2/K (LMS2, R. Ü2/K), 24114 Kiel

Titel: Approximating Geometric Knapsack via L-packings

Abstract: Joint work with: Waldo Galvez, Sandy Heydrich, Salvatore Ingala,
Arindam Khan, Andreas Wiese

In the 2-dimensional geometric knapsack problem (2DK) we are given a
set of n axis-aligned rectangular items, each one with an associated
profit, and an axis-aligned square knapsack. The goal is to find a
(non-overlapping) packing of a maximum profit subset of items inside
the knapsack (without rotating items). The best-known polynomial-time
approximation factor for this problem (even just in the cardinality
case) is 2 + ε [Jansen and Zhang, SODA 2004]. In this work we break
the 2 approximation barrier, achieving a polynomial-time 17/9 + ε <
1.89 approximation, which improves to 558/325+ ε < 1.72 in the
cardinality case.

Essentially all prior work on 2DK approximation packs items inside a
constant number of rectangular containers, where items inside each
container are packed using a simple greedy strategy. We deviate for
the first time from this setting: we show that there exists a large
profit solution where items are packed inside a constant number of
containers plus one L-shaped region at the boundary of the knapsack
which contains items that are high and narrow and items that are wide
and thin. The items of these two types possibly interact in a complex
manner at the corner of the L.

The above structural result is not enough however: the best-known
approximation ratio for the sub-problem in the L-shaped region is 2 +
ε (obtained via a trivial reduction to 1-dimensional knapsack by
considering tall or wide items only). Indeed this is one of the
simplest special settings of the problem for which this is the best
known approximation factor. As a second major, and the main
algorithmic contribution of this work, we present a PTAS for this
case. We believe that this will turn out to be useful in future work
in geometric packing problems.

We also consider the variant of the problem with rotations (2DKR),
where items can be rotated by 90 degrees. Also in this case the
best-known polynomial-time approximation factor (even for the
cardinality case) is 2 + ε [Jansen and Zhang, SODA 2004]. Exploiting
part of the machinery developed for 2DK plus a few additional ideas,
we obtain a polynomial-time 3/2 + ε-approximation for 2DKR, which
improves to 4/3 + ε in the cardinality case.

Prof. Jansen

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Sonderkolloquium, Jun.-Prof. Dr. Mattias Heinrich, Uni Lübeck / am 07.07.2017

07.07.2017 von 14:15 bis 15:45

Institut für Informatik,Christian-Albrechts-Platz 4, R.715, 24114 Kiel

Titel: Learning Sparse Binary Features for Medical Image Segmentation of the Abdomen

Abstract: In this talk, we explore the capabilities of sparse binary features for medical image segmentation. Due to insufficient contrast and anatomical shape variations local image patches rarely provide sufficient information for accurate segmentation of abdominal structures. Based on our two recent MICCAI papers, we propose to use long-range binary features to robustly capture the image context. Two different classification strategies are subsequently developed. 

First, a very fast approximate nearest neighbour search based on vantage point forests and Hamming distances between feature strings is presented. The classifier can be learned and applied to new data in few seconds. The approach reaches state-of-the-art performance for larger organs on the VISCERAL3 benchmark.

Second, we develop a deep neural network architecture that combines a local CNN path with a new contextual path that encodes the sparse binary features. Following the ideas from Network-in-Network, 1x1 convolutions are employed to learn the best combination of different binary offset locations. We demonstrate experimentally that this restricted feature extraction in the first layer enables to regularise the network with a huge receptive field and leads to short training times of less than 10 minutes. Using only 1 million trainable parameters, the model achieves a accuracy of 64.5% Dice, which is comparable to the best performing, much more complex deep CNN approach for pancreas segmentation.

Finally, the potential use of learned binary features for other tasks in medical image analysis, such as image registration and disease classification will be discussed.

 

Prof. Meyer

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Kolloquiumsvortrag, Prof. Grandoni, IDSIA USI-SUPSI in Lugano / am 07.07.2017

07.07.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, Raum Ü2/K (LMS2, R. Ü2/K), 24114 Kiel

Titel: Approximating Geometric Knapsack via L-packings

Abstract: Joint work with: Waldo Galvez, Sandy Heydrich, Salvatore Ingala,
Arindam Khan, Andreas Wiese

In the 2-dimensional geometric knapsack problem (2DK) we are given a
set of n axis-aligned rectangular items, each one with an associated
profit, and an axis-aligned square knapsack. The goal is to find a
(non-overlapping) packing of a maximum profit subset of items inside
the knapsack (without rotating items). The best-known polynomial-time
approximation factor for this problem (even just in the cardinality
case) is 2 + ε [Jansen and Zhang, SODA 2004]. In this work we break
the 2 approximation barrier, achieving a polynomial-time 17/9 + ε <
1.89 approximation, which improves to 558/325+ ε < 1.72 in the
cardinality case.

Essentially all prior work on 2DK approximation packs items inside a
constant number of rectangular containers, where items inside each
container are packed using a simple greedy strategy. We deviate for
the first time from this setting: we show that there exists a large
profit solution where items are packed inside a constant number of
containers plus one L-shaped region at the boundary of the knapsack
which contains items that are high and narrow and items that are wide
and thin. The items of these two types possibly interact in a complex
manner at the corner of the L.

The above structural result is not enough however: the best-known
approximation ratio for the sub-problem in the L-shaped region is 2 +
ε (obtained via a trivial reduction to 1-dimensional knapsack by
considering tall or wide items only). Indeed this is one of the
simplest special settings of the problem for which this is the best
known approximation factor. As a second major, and the main
algorithmic contribution of this work, we present a PTAS for this
case. We believe that this will turn out to be useful in future work
in geometric packing problems.

We also consider the variant of the problem with rotations (2DKR),
where items can be rotated by 90 degrees. Also in this case the
best-known polynomial-time approximation factor (even for the
cardinality case) is 2 + ε [Jansen and Zhang, SODA 2004]. Exploiting
part of the machinery developed for 2DK plus a few additional ideas,
we obtain a polynomial-time 3/2 + ε-approximation for 2DKR, which
improves to 4/3 + ε in the cardinality case.

Prof. Jansen

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Sonderkolloquium, Jun.-Prof. Dr. Mattias Heinrich, Uni Lübeck / am 07.07.2017

07.07.2017 von 14:15 bis 15:45

Institut für Informatik,Christian-Albrechts-Platz 4, R.715, 24114 Kiel

Titel: Learning Sparse Binary Features for Medical Image Segmentation of the Abdomen

Abstract: In this talk, we explore the capabilities of sparse binary features for medical image segmentation. Due to insufficient contrast and anatomical shape variations local image patches rarely provide sufficient information for accurate segmentation of abdominal structures. Based on our two recent MICCAI papers, we propose to use long-range binary features to robustly capture the image context. Two different classification strategies are subsequently developed. 

First, a very fast approximate nearest neighbour search based on vantage point forests and Hamming distances between feature strings is presented. The classifier can be learned and applied to new data in few seconds. The approach reaches state-of-the-art performance for larger organs on the VISCERAL3 benchmark.

Second, we develop a deep neural network architecture that combines a local CNN path with a new contextual path that encodes the sparse binary features. Following the ideas from Network-in-Network, 1x1 convolutions are employed to learn the best combination of different binary offset locations. We demonstrate experimentally that this restricted feature extraction in the first layer enables to regularise the network with a huge receptive field and leads to short training times of less than 10 minutes. Using only 1 million trainable parameters, the model achieves a accuracy of 64.5% Dice, which is comparable to the best performing, much more complex deep CNN approach for pancreas segmentation.

Finally, the potential use of learned binary features for other tasks in medical image analysis, such as image registration and disease classification will be discussed.

 

Prof. Meyer

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Kolloquiumsvortrag, Carsten Grashoff / am 03.07.2017

03.07.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Piconewton-sensitive biosensors to investigate molecular forces in cells

Abstract: The ability of cells to adhere and simultaneously sense differences in tissue stiffness is crucial for organ development and function. Yet, the molecular mechanisms by which cells sense extracellular matrix rigidity have remained unknown because suitable techniques to measure mechanical forces across intracellular proteins in living cells were missing.

We therefore develop novel, single-molecule‒calibrated tension sensor modules that allow the analysis of a physiologically highly relevant force regime in cells. Our new probes are sensitive to forces of 3–5 piconewton (pN), 6–8 pN and 9–11 pN, respectively; they are characterized by fast folding/unfolding transitions, reversibility and a sharp force-response threshold (1, 2, 3). By applying these new probes to the cell adhesion proteins talin-1 and talin-2, we demonstrate that these central integrin activators establish intracellular, mechanical linkages that bear mechanical forces of about 7–10 pN upon cell adhesion and are regulated by f-actin and vinculin association. We find that the integrin–talin–actin linkage is indispensable for extracellular rigidity sensing and, surprisingly, talin isoform-specific (1). Furthermore, multiplexing distinct tension sensor constructs by dual-color FLIM reveals an unexpected intramolecular tension gradient across talin that is modulated by intracellular signals and extracellular rigidity (3).

References:

1. Austen KA et al., and Grashoff C. 2015. Nat Cell Biol.

2. Freikamp A, Cost AL, and Grashoff C. 2016. Trends Cell Biol.

3. Ringer et al., and Grashoff C. 2017. under review

Prof. Christine Selhuber-Unkel

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Kolloquiumsvortrag, Carsten Grashoff / am 03.07.2017

03.07.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Piconewton-sensitive biosensors to investigate molecular forces in cells

Abstract: The ability of cells to adhere and simultaneously sense differences in tissue stiffness is crucial for organ development and function. Yet, the molecular mechanisms by which cells sense extracellular matrix rigidity have remained unknown because suitable techniques to measure mechanical forces across intracellular proteins in living cells were missing.

We therefore develop novel, single-molecule‒calibrated tension sensor modules that allow the analysis of a physiologically highly relevant force regime in cells. Our new probes are sensitive to forces of 3–5 piconewton (pN), 6–8 pN and 9–11 pN, respectively; they are characterized by fast folding/unfolding transitions, reversibility and a sharp force-response threshold (1, 2, 3). By applying these new probes to the cell adhesion proteins talin-1 and talin-2, we demonstrate that these central integrin activators establish intracellular, mechanical linkages that bear mechanical forces of about 7–10 pN upon cell adhesion and are regulated by f-actin and vinculin association. We find that the integrin–talin–actin linkage is indispensable for extracellular rigidity sensing and, surprisingly, talin isoform-specific (1). Furthermore, multiplexing distinct tension sensor constructs by dual-color FLIM reveals an unexpected intramolecular tension gradient across talin that is modulated by intracellular signals and extracellular rigidity (3).

References:

1. Austen KA et al., and Grashoff C. 2015. Nat Cell Biol.

2. Freikamp A, Cost AL, and Grashoff C. 2016. Trends Cell Biol.

3. Ringer et al., and Grashoff C. 2017. under review

Prof. Christine Selhuber-Unkel

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Kolloquiumsvortrag, Antrittsvorlesung Prof. Kapels / am 26.06.2017

26.06.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Von der Siliziumtechnologie zu Wide-Bandgap Leistungshalbleitern

Abstract: Kontinuierliche Innovationen im Bereich der siliziumbasierten Leistungshalbleiterbauelemente ermöglichten grundlegende Fortschritte für eine effiziente dezentrale Energieversorgung, die Weiterentwicklung der Elektromobilität und energieeffiziente Stromrichter für Industrie- und Consumer-Anwendungen. Aktuelle Trends in Leistungsdichte und Gewicht werden jedoch zunehmend nicht mehr mit Halbleiterbauelementen auf Siliziumbasis erfüllt werden können. Leistungstransistoren auf Basis von SiC und GaN ermöglichen hier Zukunftspotentiale zu heben. Die Vorlesung zeigt die wesentlichen Bauelementekonzepte, aktuelle Herausforderungen und Lösungen auf.

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Kolloquiumsvortrag, Antrittsvorlesung Prof. Kapels / am 26.06.2017

26.06.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Von der Siliziumtechnologie zu Wide-Bandgap Leistungshalbleitern

Abstract: Kontinuierliche Innovationen im Bereich der siliziumbasierten Leistungshalbleiterbauelemente ermöglichten grundlegende Fortschritte für eine effiziente dezentrale Energieversorgung, die Weiterentwicklung der Elektromobilität und energieeffiziente Stromrichter für Industrie- und Consumer-Anwendungen. Aktuelle Trends in Leistungsdichte und Gewicht werden jedoch zunehmend nicht mehr mit Halbleiterbauelementen auf Siliziumbasis erfüllt werden können. Leistungstransistoren auf Basis von SiC und GaN ermöglichen hier Zukunftspotentiale zu heben. Die Vorlesung zeigt die wesentlichen Bauelementekonzepte, aktuelle Herausforderungen und Lösungen auf.

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Sonderkolloquium, Prof. R.D. Lorenz, University of Wisconsin-Madison / 23.06.2017

23.06.2017 von 13:00 bis 15:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Disruptive Paradigm Changes for Electrical Machines and Electrical Drives

Abstract: Electric machine design paradigms have been dramatically changed by the need to meet the demands for minimizing losses and smooth torque control during driving cycles with widely vary loads and speeds.  Simultaneously, new drive control paradigms systematically out-perform industry standard field oriented control (FOC) and simultaneously solve several classical problems with FOC. In addition, the internet of things is opening expansive opportunities for motor drives.  This presentation with focus on these disruptive changes in the paradigms for electric machines and electrical drives and explore the opportunities for innovation that these technologies provide.

Affiliation:

Chaired Professor and Co-Director of WEMPEC at the University of Wisconsin-Madison, in Madison, Wisconsin, USA

Short Bio:

Prof. Robert D. (Bob) Lorenz is a Life Fellow of IEEE, Past President of IEEE IAS, and Past Member of the IEEE Board of Directors. He is a Chaired Professor at the University of Wisconsin-Madison and Co-Director of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC) which just celebrated its 36th Anniversary with over 85 international sponsor firms.    He has pioneered core technologies for physics-based control design, self-sensing, flux observers, current regulators, deadbeat-direct torque and flux control, variable flux and variable magnetization state PM machines and power semiconductor temperature and strain control and has won 33 prize paper awards from the IEEE.

Prof. Liserre

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Sonderkolloquium, Prof. R.D. Lorenz, University of Wisconsin-Madison / 23.06.2017

23.06.2017 von 13:00 bis 15:00

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Disruptive Paradigm Changes for Electrical Machines and Electrical Drives

Abstract: Electric machine design paradigms have been dramatically changed by the need to meet the demands for minimizing losses and smooth torque control during driving cycles with widely vary loads and speeds.  Simultaneously, new drive control paradigms systematically out-perform industry standard field oriented control (FOC) and simultaneously solve several classical problems with FOC. In addition, the internet of things is opening expansive opportunities for motor drives.  This presentation with focus on these disruptive changes in the paradigms for electric machines and electrical drives and explore the opportunities for innovation that these technologies provide.

Affiliation:

Chaired Professor and Co-Director of WEMPEC at the University of Wisconsin-Madison, in Madison, Wisconsin, USA

Short Bio:

Prof. Robert D. (Bob) Lorenz is a Life Fellow of IEEE, Past President of IEEE IAS, and Past Member of the IEEE Board of Directors. He is a Chaired Professor at the University of Wisconsin-Madison and Co-Director of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC) which just celebrated its 36th Anniversary with over 85 international sponsor firms.    He has pioneered core technologies for physics-based control design, self-sensing, flux observers, current regulators, deadbeat-direct torque and flux control, variable flux and variable magnetization state PM machines and power semiconductor temperature and strain control and has won 33 prize paper awards from the IEEE.

Prof. Liserre

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Sonderkolloquium Prof. Tamulevicius, Technische Universität Kaunas / am 20.06.2017

20.06.2017 von 17:15 bis 18:45

Technische Fakultät, Institut für Materialwissenschaft, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Nanoparticles, nanocomposites - from optics to medicine

Abstract: Principles of deposition and applications of diamond-like carbon thin films, diamond-like carbon-based nanocomposites including metallic nanoparticles as well as capillary assisted deposition of nanoparticles will be presented, thereby concentrating on the optical, electrical  properties and the use of the assembly of particles as building blocks for optical sensors and antimicrobial surfaces. Features of localized surface plasmon effects, surface enhanced Raman scattering, detection of ultrafast energy transfer processes will be discussed.

Prof. Faupel

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Sonderkolloquium Prof. Tamulevicius, Technische Universität Kaunas / am 20.06.2017

20.06.2017 von 17:15 bis 18:45

Technische Fakultät, Institut für Materialwissenschaft, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Nanoparticles, nanocomposites - from optics to medicine

Abstract: Principles of deposition and applications of diamond-like carbon thin films, diamond-like carbon-based nanocomposites including metallic nanoparticles as well as capillary assisted deposition of nanoparticles will be presented, thereby concentrating on the optical, electrical  properties and the use of the assembly of particles as building blocks for optical sensors and antimicrobial surfaces. Features of localized surface plasmon effects, surface enhanced Raman scattering, detection of ultrafast energy transfer processes will be discussed.

Prof. Faupel

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Kolloquiumsvortrag, Prof. Dr.-Ing. Mücklich, Functional Materials, Dept. Mat. Science & Engineering, Saarland University / am 19.06.2017

19.06.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Optimized functionality by 3D microstructure research and efficient surface patterning

Abstract: In the introduction a short overview will be given concerning the three units of the institute, such as the chair for functions materials which is dedicated to fundamental research and teaching, the European School of Materials, which is focused on the international study programs on all academic levels and the Material Engineering Center Saarland, which is promoted by applied research and transfer activities. Then some of the research activities will be discussed based on three main questions:

-          How does 3D microstructure research on the micro, nano and atomic scale help to understand the quantitative relations between microstructure formation and properties  

-          How does the initial 3D morphology control the processing and formation of microstructures and

-          How can Direct Laser Interference Patterning be exploited to design optimized surface functionalities

Prof. Quandt

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Kolloquiumsvortrag, Prof. Dr.-Ing. Mücklich, Functional Materials, Dept. Mat. Science & Engineering, Saarland University / am 19.06.2017

19.06.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Optimized functionality by 3D microstructure research and efficient surface patterning

Abstract: In the introduction a short overview will be given concerning the three units of the institute, such as the chair for functions materials which is dedicated to fundamental research and teaching, the European School of Materials, which is focused on the international study programs on all academic levels and the Material Engineering Center Saarland, which is promoted by applied research and transfer activities. Then some of the research activities will be discussed based on three main questions:

-          How does 3D microstructure research on the micro, nano and atomic scale help to understand the quantitative relations between microstructure formation and properties  

-          How does the initial 3D morphology control the processing and formation of microstructures and

-          How can Direct Laser Interference Patterning be exploited to design optimized surface functionalities

Prof. Quandt

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Kolloquiumsvortrag, Prof. Herbert Jäger, Jacobs University Bremen / am 12.06.2017

12.06.2017 von 17:15 bis 18:45

Institut für Elektrotechnik und Informationstechnik, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Thema: An introduction to Reservoir Computing


Abstract: Recurrent neural networks (RNNs) are general approximators for nonlinear dynamical systems and have recently become widely used in the "deep learning" field of machine learning, especially for speech and language processing tasks. For instance, Google's speech recognition and language translation services are based on RNNs.

However, the deep learning set-ups for RNN training are computationally very expensive, require very large volumes of training data, and need high-precision numerical processing. For such reasons, deep-learning variants of RNNs are problematic in fields where training data are scarce, where fast and cheap algorithms are desired, or where noisy or low-precision hardware is to be used. This is often the case in domains of nonlinear signal processing, control, brain-machine interfacing, or biomedical signal processing.

Reservoir Computing (RC) is an alternative machine learning approach for RNNs which is in many aspects complementary to the ways of deep learning. In RC, a large, random, possibly low-precision and noisy RNN is used as a nonlinear excitable medium - called the "reservoir" - which is driven by an input signal. The reservoir itself is not adapted or trained. Instead, only a "readout" mechanism is trained, which assembles the desired output signal from the large variety of random, excited signals within the reservoir. This readout training is cheap - typically just a linear regression. RC has become a popular approach in research that aims at useful computations on the basis on unconventional hardware (non-digital, noisy, low-precision).

The talk gives an introduction to the basic principles and variants of RC. Numerous examples will be presented according to wishes from the audience.

Prof. Hermann Kohlstedt

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Kolloquiumsvortrag, Prof. Herbert Jäger, Jacobs University Bremen / am 12.06.2017

12.06.2017 von 17:15 bis 18:45

Institut für Elektrotechnik und Informationstechnik, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Thema: An introduction to Reservoir Computing


Abstract: Recurrent neural networks (RNNs) are general approximators for nonlinear dynamical systems and have recently become widely used in the "deep learning" field of machine learning, especially for speech and language processing tasks. For instance, Google's speech recognition and language translation services are based on RNNs.

However, the deep learning set-ups for RNN training are computationally very expensive, require very large volumes of training data, and need high-precision numerical processing. For such reasons, deep-learning variants of RNNs are problematic in fields where training data are scarce, where fast and cheap algorithms are desired, or where noisy or low-precision hardware is to be used. This is often the case in domains of nonlinear signal processing, control, brain-machine interfacing, or biomedical signal processing.

Reservoir Computing (RC) is an alternative machine learning approach for RNNs which is in many aspects complementary to the ways of deep learning. In RC, a large, random, possibly low-precision and noisy RNN is used as a nonlinear excitable medium - called the "reservoir" - which is driven by an input signal. The reservoir itself is not adapted or trained. Instead, only a "readout" mechanism is trained, which assembles the desired output signal from the large variety of random, excited signals within the reservoir. This readout training is cheap - typically just a linear regression. RC has become a popular approach in research that aims at useful computations on the basis on unconventional hardware (non-digital, noisy, low-precision).

The talk gives an introduction to the basic principles and variants of RC. Numerous examples will be presented according to wishes from the audience.

Prof. Hermann Kohlstedt

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Sonderkolloquium, Prof. Remus Teodorescu, Universität Aalborg / 12.06.2017

12.06.2017 von 15:15 bis 16:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Modular Multilevel Converter Research at Aalborg University

Abstract:This presentation is aiming on summarizing the main features of the recently published book: Design, Control, and Application of Modular Multilevel Converters for HVDC Transmission Systems, ISBN: 978-1-118-85156-2, Wiley 2016http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1118851560.html#. Special focus will be on Control under unbalanced conditions of MMC.

Prof. Liserre

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Sonderkolloquium, Prof. Remus Teodorescu, Universität Aalborg / 12.06.2017

12.06.2017 von 15:15 bis 16:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Modular Multilevel Converter Research at Aalborg University

Abstract:This presentation is aiming on summarizing the main features of the recently published book: Design, Control, and Application of Modular Multilevel Converters for HVDC Transmission Systems, ISBN: 978-1-118-85156-2, Wiley 2016http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1118851560.html#. Special focus will be on Control under unbalanced conditions of MMC.

Prof. Liserre

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Kolloquiumsvortrag, PhD Tammy Riklin Raviv, Ben-Gurion-University of the Negev, Beer Sheva, Israel / am 09.06.2017

09.06.2017 von 13:30 bis 15:00

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel:

Ensemble of Expert Deep Neural Networks for Spatio-Temporal Denoising of Contrast-Enhanced MRI Sequences

Abstract:

Abstract: Dynamic contrast-enhanced MRI (DCE-MRI) is an imaging protocol where MRI scans are acquired repetitively throughout the injection of a contrast agent. The analysis of dynamic scans is widely used for the detection and quantification of blood-brain barrier (BBB) permeability. Extraction of the pharmacokinetic (PK) parameters from the DCE-MRI concentration curves allows quantitative assessment of the integrity of the BBB functionality. However, curve fitting required for the analysis of DCE-MRI data is error-prone as the dynamic scans are subject to non-white, spatially dependent and anisotropic noise.

We present a novel spatio-temporal framework based on Deep Convolution Neural Networks (DCNNs) to address the DCE-MRI denoising challenges. This is accomplished by an ensemble of expert DCNNs constructed as deep autoencoders, where each is trained on a specific subset of the input space to accommodate different noise characteristics and curve prototypes. The most likely reconstructed curves are then chosen using a classifier DCNN followed by a quadratic programming optimization. As clean signals (ground-truth)

for training are not available, a fully automatic model for generating realistic training sets with complex nonlinear dynamics is introduced. The proposed approach has been applied to full and even temporally down-sampled DCE-MRI datasets acquired by MRI machines in different locations and of different manufacturers and is shown to favorably compare to state-of-the-art denoising methods.

Prof. Carsten Meyer

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Kolloquiumsvortrag, PhD Tammy Riklin Raviv, Ben-Gurion-University of the Negev, Beer Sheva, Israel / am 09.06.2017

09.06.2017 von 13:30 bis 15:00

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel:

Ensemble of Expert Deep Neural Networks for Spatio-Temporal Denoising of Contrast-Enhanced MRI Sequences

Abstract:

Abstract: Dynamic contrast-enhanced MRI (DCE-MRI) is an imaging protocol where MRI scans are acquired repetitively throughout the injection of a contrast agent. The analysis of dynamic scans is widely used for the detection and quantification of blood-brain barrier (BBB) permeability. Extraction of the pharmacokinetic (PK) parameters from the DCE-MRI concentration curves allows quantitative assessment of the integrity of the BBB functionality. However, curve fitting required for the analysis of DCE-MRI data is error-prone as the dynamic scans are subject to non-white, spatially dependent and anisotropic noise.

We present a novel spatio-temporal framework based on Deep Convolution Neural Networks (DCNNs) to address the DCE-MRI denoising challenges. This is accomplished by an ensemble of expert DCNNs constructed as deep autoencoders, where each is trained on a specific subset of the input space to accommodate different noise characteristics and curve prototypes. The most likely reconstructed curves are then chosen using a classifier DCNN followed by a quadratic programming optimization. As clean signals (ground-truth)

for training are not available, a fully automatic model for generating realistic training sets with complex nonlinear dynamics is introduced. The proposed approach has been applied to full and even temporally down-sampled DCE-MRI datasets acquired by MRI machines in different locations and of different manufacturers and is shown to favorably compare to state-of-the-art denoising methods.

Prof. Carsten Meyer

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Sonderkolloquium, Prof. Dr. Raj, Universität Agra, Indien / am 08.06.2017

08.06.2017 von 11:30 bis 13:00

Institut für Informatik, Christian-Albrechts-Platz 4, Raum: 910 (CAP 4), 24118 Kiel

Titel: Finite Element Modelling and Simulation of Selected Bulk Nano-material Processing Techniques

Abstract: A brief review of the material modeling such as visco-plastic, coupled thermo visco-plastic along with mathematical formulation is presented with application to forming of Bulk Nano-structured Materials using Severe Plastic Deformation(SPD). The material is assumed to be homogeneous, isotropic, incompressible. Elasticity is neglected and the material behavior chosen is given by the Norton-Hoff law. A power law is used to simulate the friction between the die and the work-piece. The flow problem with a given temperature distribution is solved simultaneously with the heat diffusion equation. Using the Penalty approach to enforce approximate incompressibility, the Variational principle is applied. This finds the velocity field solution of the problem by minimizing the functional. The coupling between the mechanical and the thermal problems is obtained through the dependency of the consistency of the material with temperature. Being a non-steady state process, SPD is analyzed by using small steady-like deformation steps. The usual finite element method is used to discretize the two problems at a given state Ω(t), and in the axi-symmetrical case the interpolation of the variables is performed in the (r2, z) space. The SPD processes that are modeled are Equal Channel Angular Pressing (ECAP), Twist Extrusion (TE), Accumulative Roll Bonding(ARB), Repetitive Corrugation and Straightening (RCS) and High Pressure Torsion (HPT). Finite Element Modeling and experimentation of these SPD processes is presented in this paper.

Prof. Srivastav

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Sonderkolloquium, Prof. Dr. Raj, Universität Agra, Indien / am 08.06.2017

08.06.2017 von 11:30 bis 13:00

Institut für Informatik, Christian-Albrechts-Platz 4, Raum: 910 (CAP 4), 24118 Kiel

Titel: Finite Element Modelling and Simulation of Selected Bulk Nano-material Processing Techniques

Abstract: A brief review of the material modeling such as visco-plastic, coupled thermo visco-plastic along with mathematical formulation is presented with application to forming of Bulk Nano-structured Materials using Severe Plastic Deformation(SPD). The material is assumed to be homogeneous, isotropic, incompressible. Elasticity is neglected and the material behavior chosen is given by the Norton-Hoff law. A power law is used to simulate the friction between the die and the work-piece. The flow problem with a given temperature distribution is solved simultaneously with the heat diffusion equation. Using the Penalty approach to enforce approximate incompressibility, the Variational principle is applied. This finds the velocity field solution of the problem by minimizing the functional. The coupling between the mechanical and the thermal problems is obtained through the dependency of the consistency of the material with temperature. Being a non-steady state process, SPD is analyzed by using small steady-like deformation steps. The usual finite element method is used to discretize the two problems at a given state Ω(t), and in the axi-symmetrical case the interpolation of the variables is performed in the (r2, z) space. The SPD processes that are modeled are Equal Channel Angular Pressing (ECAP), Twist Extrusion (TE), Accumulative Roll Bonding(ARB), Repetitive Corrugation and Straightening (RCS) and High Pressure Torsion (HPT). Finite Element Modeling and experimentation of these SPD processes is presented in this paper.

Prof. Srivastav

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Kolloquiumsvortrag, Prof. Dr. Helmut Harbrecht, Uni Basel / am 02.06.2017

02.06.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: On multilevel quadrature for elliptic partial differential equations with random input

Abstract: This talk is dedicated to multilevel quadrature methods for the rapid solution of partial differential equations with a random input parameter. The key idea of such approaches is a sparse-grid approximation of the occurring product space between the stochastic and the spatial variable. We develop the mathematical theory and present error estimates for the computation of the solution’s moments with focus on the mean and the variance in case of second order elliptic boundary value problems with random diffusion. In particular, the present framework covers the multilevel Monte Carlo method and the multilevel quasi-Monte Carlo method as special cases. The theoretical findings are supplemented by numerical experiments.

Prof. Börm

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Kolloquiumsvortrag, Prof. Dr. Helmut Harbrecht, Uni Basel / am 02.06.2017

02.06.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: On multilevel quadrature for elliptic partial differential equations with random input

Abstract: This talk is dedicated to multilevel quadrature methods for the rapid solution of partial differential equations with a random input parameter. The key idea of such approaches is a sparse-grid approximation of the occurring product space between the stochastic and the spatial variable. We develop the mathematical theory and present error estimates for the computation of the solution’s moments with focus on the mean and the variance in case of second order elliptic boundary value problems with random diffusion. In particular, the present framework covers the multilevel Monte Carlo method and the multilevel quasi-Monte Carlo method as special cases. The theoretical findings are supplemented by numerical experiments.

Prof. Börm

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Kolloquiumsvortrag, Dr. Barth / am 22.05.2017

22.05.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Hochfrequenz-Filterdesign unter Berücksichtigung hoher Transmissionsleistung

Abstract: Das Design von Hohlleiterfiltern mit Hilfe der Softwareprogramme HFSS, MATHCAD und AWR wird beschrieben. Das Design berücksichtigt die hohe Transmissionsleistung (hier 40KW gepulst), die bei Radargeräten auftritt und den Entwickler vor besondere Herausforderung stellt. Die Designmethode ist äußerst präzise, so dass die Anforderungen an das Filter schon im ersten Designschritt erreicht werden. Eine Abstimmung, die Feldkonzentrationen und damit Überschläge in den Filterresonatoren hervorrufen könnten, ist damit nicht nötig. Trotzdem wird eine Abstimmmethode bei hohen Feldstärken diskutiert.

Ein Filter, das für die Luftraumüberwachung eines Flughafens konstruiert wurde und dort auch seit Jahren in Betrieb ist, wird als Beispiel vorgestellt.

Prof. Höft

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Kolloquiumsvortrag, Dr. Barth / am 22.05.2017

22.05.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Hochfrequenz-Filterdesign unter Berücksichtigung hoher Transmissionsleistung

Abstract: Das Design von Hohlleiterfiltern mit Hilfe der Softwareprogramme HFSS, MATHCAD und AWR wird beschrieben. Das Design berücksichtigt die hohe Transmissionsleistung (hier 40KW gepulst), die bei Radargeräten auftritt und den Entwickler vor besondere Herausforderung stellt. Die Designmethode ist äußerst präzise, so dass die Anforderungen an das Filter schon im ersten Designschritt erreicht werden. Eine Abstimmung, die Feldkonzentrationen und damit Überschläge in den Filterresonatoren hervorrufen könnten, ist damit nicht nötig. Trotzdem wird eine Abstimmmethode bei hohen Feldstärken diskutiert.

Ein Filter, das für die Luftraumüberwachung eines Flughafens konstruiert wurde und dort auch seit Jahren in Betrieb ist, wird als Beispiel vorgestellt.

Prof. Höft

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Kolloquiumsvortrag, Prof. Knut Graichen, Institut für Mess-, Regel- und Mikrotechnik, Universität Ulm / am 15.05.2017

15.05.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Eingebettete nichtlineare Optimierung und MPC im (Sub-)Millisekundenbereich

Abstract: Nichtlineare Optimierungsverfahren und deren Anwendung im Zusammenhang mit der nichtlinearen modellprädiktiven Regelung (NMPC) sind in der Regelungstechnik insbesondere für dynamische Systeme mit mehreren Stellgrößen und zur Berücksichtigung von Systembeschränkungen von zunehmender Bedeutung. Eine Herausforderung bei der Umsetzung dieser Verfahren in der Praxis ist jedoch der hohe numerische Aufwand und die algorithmische Komplexität, insbesondere bei hochdynamischen Systemen mit Abtastzeiten im (Sub-)Millisekundenbereich. Die Problematik der Umsetzbarkeit wird durch die Tatsache weiter verschärft, dass Hardware-Lösungen in der industriellen Praxis häufig sehr limitierte Ressourcen besitzen. Als Beispiele seien Speicherprogrammierbare Steuerungen (SPS) oder Steuergeräte (Electronic Control Unit – ECU) genannt. Diesen Herausforderungen kann im Sinne eines eingebetteten Entwurfs durch die Verwendung von zugeschnittenen Optimierungsalgorithmen in Kombination mit einer echtzeitfähigen Auswertung begegnet werden.
Im Hinblick auf die oben genannten Herausforderungen präsentiert der Vortrag einen Ansatz zur nichtlinearen dynamischen Optimierung und modellprädiktiven Regelung, der eine echtzeitfähige Umsetzung selbst auf leistungsschwacher Hardware ermöglicht. Neben der methodischen und algorithmischen Vorstellung wird das Verfahren anhand von ausgewählten mechatronischen Beispielen erläutert.

Prof. Thomas Meurer

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Kolloquiumsvortrag, Prof. Knut Graichen, Institut für Mess-, Regel- und Mikrotechnik, Universität Ulm / am 15.05.2017

15.05.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Eingebettete nichtlineare Optimierung und MPC im (Sub-)Millisekundenbereich

Abstract: Nichtlineare Optimierungsverfahren und deren Anwendung im Zusammenhang mit der nichtlinearen modellprädiktiven Regelung (NMPC) sind in der Regelungstechnik insbesondere für dynamische Systeme mit mehreren Stellgrößen und zur Berücksichtigung von Systembeschränkungen von zunehmender Bedeutung. Eine Herausforderung bei der Umsetzung dieser Verfahren in der Praxis ist jedoch der hohe numerische Aufwand und die algorithmische Komplexität, insbesondere bei hochdynamischen Systemen mit Abtastzeiten im (Sub-)Millisekundenbereich. Die Problematik der Umsetzbarkeit wird durch die Tatsache weiter verschärft, dass Hardware-Lösungen in der industriellen Praxis häufig sehr limitierte Ressourcen besitzen. Als Beispiele seien Speicherprogrammierbare Steuerungen (SPS) oder Steuergeräte (Electronic Control Unit – ECU) genannt. Diesen Herausforderungen kann im Sinne eines eingebetteten Entwurfs durch die Verwendung von zugeschnittenen Optimierungsalgorithmen in Kombination mit einer echtzeitfähigen Auswertung begegnet werden.
Im Hinblick auf die oben genannten Herausforderungen präsentiert der Vortrag einen Ansatz zur nichtlinearen dynamischen Optimierung und modellprädiktiven Regelung, der eine echtzeitfähige Umsetzung selbst auf leistungsschwacher Hardware ermöglicht. Neben der methodischen und algorithmischen Vorstellung wird das Verfahren anhand von ausgewählten mechatronischen Beispielen erläutert.

Prof. Thomas Meurer

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Kolloquiumsvortrag, Prof. Armin Iske, Universität Hamburg / am 12.05.2017

12.05.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Error Estimates and Convergence Rates for Filtered Back Projection.

Abstract: We consider the approximation of target functions from fractional Sobolev spaces by the method of filtered back projection (FBP), which gives an inversion of the Radon transform. To this end, we analyze the intrinsic FBP approximation error which is incurred by the use of a low-pass filter with finite bandwidth, before we prove $L^2$-error estimates on Sobolev spaces of fractional order. The obtained error bounds are affine-linear with respect to the distance between the filter's window function and the constant function $1$ in the $L^\infty$-norm. With assuming more regularity for the window function, we refine the error estimates to prove convergence for the FBP approximation in the $L^2$-norm as the filter's bandwidth goes to infinity. We finally give asymptotic convergence rates in terms of the bandwidth of the low-pass filter and the smoothness of the target function.

Prof. Börm

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Kolloquiumsvortrag, Prof. Armin Iske, Universität Hamburg / am 12.05.2017

12.05.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Error Estimates and Convergence Rates for Filtered Back Projection.

Abstract: We consider the approximation of target functions from fractional Sobolev spaces by the method of filtered back projection (FBP), which gives an inversion of the Radon transform. To this end, we analyze the intrinsic FBP approximation error which is incurred by the use of a low-pass filter with finite bandwidth, before we prove $L^2$-error estimates on Sobolev spaces of fractional order. The obtained error bounds are affine-linear with respect to the distance between the filter's window function and the constant function $1$ in the $L^\infty$-norm. With assuming more regularity for the window function, we refine the error estimates to prove convergence for the FBP approximation in the $L^2$-norm as the filter's bandwidth goes to infinity. We finally give asymptotic convergence rates in terms of the bandwidth of the low-pass filter and the smoothness of the target function.

Prof. Börm

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Sonderkolloquium, Prof. Dr. Mayr, Universität Klagenfurt / 10.05.2017

10.05.2017 von 17:00 bis 18:30

Hermann-Rodewald-Str. 3, 408a, 24118 Kiel

Titel: Konzeptuelle Modellierung – eine Disziplin mit Potenzial

Abstract: Die Welt ist voll von Menschen, die konzeptuell modellieren, sich dessen aber nicht bewusst sind und daher pragmatisch agieren. Dies ist nicht weiter schlimm. Es sei denn, es handelt sich um ExpertInnen der Informatik und angrenzender Gebiete, die es besser wissen sollen. Denn viele und vor allem sehr teure Probleme im Umfeld der Erstellung und des Betriebs von Softwaresystemen – zu denen ich natürlich auch datenintensive Informationssysteme zähle – entstehen durch unzureichende oder unsachgemäße Modellierung: selbst wenn man glaubt, hierauf großes Augenmerk zu legen bzw. gelegt zu haben.

Die Schuld hieran liegt nur zu einem kleineren Teil an den in der Praxis Handelnden selbst. Denn als Konsumenten von Lehrbüchern, Kursen usw. können sie es kaum besser wissen. Verantwortlich sind  vor allem diejenigen, die im Bereich der Modellierungsforschung arbeiten und lehren, mich eingeschlossen. Denn es ist uns offenbar nicht gelungen, (konzeptuelle) Modellierungsmethoden so zu gestalten und zu vermitteln, dass an ihrer systematischen und erfolgsbringenden Verwendung kein Weg vorbeiführt. Also muss man die Ursachen analysieren und daraus Konsequenzen für die Zukunft ziehen. Hierzu soll dieser Vortrag beitragen.

Zunächst werde ich versuchen, einen Eindruck davon zu vermitteln, was falsch läuft: vom Fehlen einer scharfen Definition des Begriffes „Konzeptuelle Modellierung“ selbst, über die anschwellende Ontologieflut, die offenbar den Mangel an Standards und Konstruktionsregeln ausgleichen soll, bis zum damit verbundenen Begriffs- und Methodenchaos.

Hiervon ausgehend werde ich aufzeigen, wohin, und mit welchen meist einfachen Mitteln, die Reise gehen könnte, ohne dass wieder (vermeintlich) Neues zu erfinden, zu predigen und zu verkraften wäre: über vieles wurde nämlich bereits nachgedacht und geschrieben, teils unbeachtet, teils wieder vergessen.

Heinrich C. Mayr ist emeritierter Ordentlicher Universitätsprofessor an der Alpen-Adria-Universität Klagenfurt (AAU), an der er seit 1990 tätig ist und die Forschungsgruppe Application Engineering leitet. Zuvor war er Assistent und Hochschulassistent an der Universität Karlsruhe (heute KIT), Gastprofessor an verschiedenen Universitäten im In- und Ausland und geschäftsführender Gesellschafter eines Softwareunternehmens. Seine Forschungsergebnisse sind in über 200 meist begutachteten (peer review) Veröffentlichungen dokumentiert. Sie betreffen im Wesentlichen Entwurfs- und Entwicklungsmethoden für Informationssysteme, die Modellierung im Kontext von Anforderungsanalyse, Systementwurf und Wissensmanagement, sowie die Entwicklung domänenspezifischer Modellierungssprachen. Unter anderem war er Sprecher des Fachbereichs Softwaretechnik und Informationssysteme, Vizepräsident und Präsident der Gesellschaft für Informatik (GI), Aufsichtsratsvorsitzender der Stadtwerke Klagenfurt AG, Aufsichtsratsmitglied der FH Kärnten, Hochschulrat der Pädagogischen Hochschule Kärnten, acht Jahre Dekan der seinerzeitigen Fakultät für Wirtschaftswissenschaften und Informatik und sechs Jahre Rektor der AAU. Derzeit ist er Hauptherausgeber der Lecture Notes in Informatics (LNI), Chairman des ER Steering Committee, Vorsitzender des Beirats des Software Internet Cluster SIC und Mitglied des Fachausschusses “Wirtschaftsinformatik” der  ASIIN.

Prof. Thalheim

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Sonderkolloquium, Prof. Dr. Mayr, Universität Klagenfurt / 10.05.2017

10.05.2017 von 17:00 bis 18:30

Hermann-Rodewald-Str. 3, 408a, 24118 Kiel

Titel: Konzeptuelle Modellierung – eine Disziplin mit Potenzial

Abstract: Die Welt ist voll von Menschen, die konzeptuell modellieren, sich dessen aber nicht bewusst sind und daher pragmatisch agieren. Dies ist nicht weiter schlimm. Es sei denn, es handelt sich um ExpertInnen der Informatik und angrenzender Gebiete, die es besser wissen sollen. Denn viele und vor allem sehr teure Probleme im Umfeld der Erstellung und des Betriebs von Softwaresystemen – zu denen ich natürlich auch datenintensive Informationssysteme zähle – entstehen durch unzureichende oder unsachgemäße Modellierung: selbst wenn man glaubt, hierauf großes Augenmerk zu legen bzw. gelegt zu haben.

Die Schuld hieran liegt nur zu einem kleineren Teil an den in der Praxis Handelnden selbst. Denn als Konsumenten von Lehrbüchern, Kursen usw. können sie es kaum besser wissen. Verantwortlich sind  vor allem diejenigen, die im Bereich der Modellierungsforschung arbeiten und lehren, mich eingeschlossen. Denn es ist uns offenbar nicht gelungen, (konzeptuelle) Modellierungsmethoden so zu gestalten und zu vermitteln, dass an ihrer systematischen und erfolgsbringenden Verwendung kein Weg vorbeiführt. Also muss man die Ursachen analysieren und daraus Konsequenzen für die Zukunft ziehen. Hierzu soll dieser Vortrag beitragen.

Zunächst werde ich versuchen, einen Eindruck davon zu vermitteln, was falsch läuft: vom Fehlen einer scharfen Definition des Begriffes „Konzeptuelle Modellierung“ selbst, über die anschwellende Ontologieflut, die offenbar den Mangel an Standards und Konstruktionsregeln ausgleichen soll, bis zum damit verbundenen Begriffs- und Methodenchaos.

Hiervon ausgehend werde ich aufzeigen, wohin, und mit welchen meist einfachen Mitteln, die Reise gehen könnte, ohne dass wieder (vermeintlich) Neues zu erfinden, zu predigen und zu verkraften wäre: über vieles wurde nämlich bereits nachgedacht und geschrieben, teils unbeachtet, teils wieder vergessen.

Heinrich C. Mayr ist emeritierter Ordentlicher Universitätsprofessor an der Alpen-Adria-Universität Klagenfurt (AAU), an der er seit 1990 tätig ist und die Forschungsgruppe Application Engineering leitet. Zuvor war er Assistent und Hochschulassistent an der Universität Karlsruhe (heute KIT), Gastprofessor an verschiedenen Universitäten im In- und Ausland und geschäftsführender Gesellschafter eines Softwareunternehmens. Seine Forschungsergebnisse sind in über 200 meist begutachteten (peer review) Veröffentlichungen dokumentiert. Sie betreffen im Wesentlichen Entwurfs- und Entwicklungsmethoden für Informationssysteme, die Modellierung im Kontext von Anforderungsanalyse, Systementwurf und Wissensmanagement, sowie die Entwicklung domänenspezifischer Modellierungssprachen. Unter anderem war er Sprecher des Fachbereichs Softwaretechnik und Informationssysteme, Vizepräsident und Präsident der Gesellschaft für Informatik (GI), Aufsichtsratsvorsitzender der Stadtwerke Klagenfurt AG, Aufsichtsratsmitglied der FH Kärnten, Hochschulrat der Pädagogischen Hochschule Kärnten, acht Jahre Dekan der seinerzeitigen Fakultät für Wirtschaftswissenschaften und Informatik und sechs Jahre Rektor der AAU. Derzeit ist er Hauptherausgeber der Lecture Notes in Informatics (LNI), Chairman des ER Steering Committee, Vorsitzender des Beirats des Software Internet Cluster SIC und Mitglied des Fachausschusses “Wirtschaftsinformatik” der  ASIIN.

Prof. Thalheim

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Kolloquiumsvortrag, Prof. Jacquelien Scherpen von der Universität Groningen (NL) / am 08.05.2017

08.05.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Passivity based control techniques for (micro-)grid control

Abstract: In this presentation I will discuss some physical modeling consideration for grid models, and the various devices in the grid, such as synchronous generators and inverter models for the embedding of renewables. Furthermore, the (passivity based) control possibilities and difficulties of networks with such generating devices will be discussed, as well as control considerations for inverters. Finally, a more simple OPF control model for microgrids is considered in the analysis.

Prof. Thomas Meurer/Prof. Marco Liserre

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Kolloquiumsvortrag, Prof. Jacquelien Scherpen von der Universität Groningen (NL) / am 08.05.2017

08.05.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Passivity based control techniques for (micro-)grid control

Abstract: In this presentation I will discuss some physical modeling consideration for grid models, and the various devices in the grid, such as synchronous generators and inverter models for the embedding of renewables. Furthermore, the (passivity based) control possibilities and difficulties of networks with such generating devices will be discussed, as well as control considerations for inverters. Finally, a more simple OPF control model for microgrids is considered in the analysis.

Prof. Thomas Meurer/Prof. Marco Liserre

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Sonderkolloquium, Prof. Thomas Plagemann / Prof. Vera Goebel, Universität Oslo / am 04.05.2017

04.05.2017 von 16:30 bis 18:00

ZBW, Düsternbrooker Weg 120, 24105 Kiel, Raum B024

Titel: A Platform for fine-granular migration of multimedia applications

Abstract: As a step towards mobile and ubiquitous computing, the TRAMP Real-time Application Mobility Platform (TRAMP) enables secure and user-friendly migration of multimedia application components. The motivating factors are device and user mobiliy, i.e., to let the user determine where application components should execute at all times. In order to organize and locate roaming devices, a decentralized peer-to-peer overlay is developed. To provide location transparency for application developers and enable efficient data sharing among application components, an API is provided that hides whether shared memory or latency optimized network distribution is used to share data. The problem of open TCP connections to third-party applications is solved with a proxy-based approach. Multimedia applications are especially sensitive to service interruptions that can be caused by migration, and a new approach for check-pointing, state transfer and resuming an application with minimal freeze time is therefore introduced. The evaluation of TRAMP shows that this optimization for low freeze time has significant effect. For example, migrating the Skype video-conferencing application with TRAMP reduces the average freeze time from 41.1 seconds with legacy approaches to 213 milliseconds. Further results from the empirical evaluation of TRAMP demonstrate that it has no negative impact on the Quality of Experience.

Prof. Scherp

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Sonderkolloquium, Prof. Thomas Plagemann / Prof. Vera Goebel, Universität Oslo / am 04.05.2017

04.05.2017 von 16:30 bis 18:00

ZBW, Düsternbrooker Weg 120, 24105 Kiel, Raum B024

Titel: A Platform for fine-granular migration of multimedia applications

Abstract: As a step towards mobile and ubiquitous computing, the TRAMP Real-time Application Mobility Platform (TRAMP) enables secure and user-friendly migration of multimedia application components. The motivating factors are device and user mobiliy, i.e., to let the user determine where application components should execute at all times. In order to organize and locate roaming devices, a decentralized peer-to-peer overlay is developed. To provide location transparency for application developers and enable efficient data sharing among application components, an API is provided that hides whether shared memory or latency optimized network distribution is used to share data. The problem of open TCP connections to third-party applications is solved with a proxy-based approach. Multimedia applications are especially sensitive to service interruptions that can be caused by migration, and a new approach for check-pointing, state transfer and resuming an application with minimal freeze time is therefore introduced. The evaluation of TRAMP shows that this optimization for low freeze time has significant effect. For example, migrating the Skype video-conferencing application with TRAMP reduces the average freeze time from 41.1 seconds with legacy approaches to 213 milliseconds. Further results from the empirical evaluation of TRAMP demonstrate that it has no negative impact on the Quality of Experience.

Prof. Scherp

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Kolloquiumsvortrag, Prof. Massimo Guarnieri, University Padua (Italien) / am 24.04.2017

24.04.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Vanadium Redox Flow Batteries: Potentials and Challenges of an Emerging Storage Technology.

Abstract:  Energy storage is expected to expand its importance the next future, in order to provide increasing services, both mobile and stationary. Depending on their kind, rated powers vary from a few kilowatts (excluding portable electronics) to some gigawatts, with operating times ranging from fractions of a second to several hours and response times from milliseconds to some minutes. Electrochemical storage technologies are by far the most versatile form of energy storage to face this vast rising demand, and a huge market is soaring. Recent techno-financial analyses have forecasted investments exceeding US$10 billion/year on energy storage technologies by 2020.

The most enticing forms of electrochemical storage should allow to separated power and energy rating, in order to tailor discharge duration at will and the most promising solution for doing so at a reasonably high round-trip efficiency and at a high cycle life are flow batteries. For this reason, several major laboratories around the world are intensively researching them.

My talk will present the main feature of the most developed chemistry of flow battery, namely Vanadium Redox Flow Battery. An overview will be delivered on how they work, what are their architectures, needed ancillary technology, including power electronic interfaces, and possible applications, from small domestic end-user to smart-grid substations. The strengths, weaknesses and challenges of vanadium redox flow batteries will be highlights. A particular reference will be given to the research programs on VRFBs on-going at University of Padua, both experimental and numerical, aiming at taking them to full commercial success.

CV

Massimo Guarnieri joined the CNR (Italian National Council of Researches) in 1882 and the University of Padua in 1983, where he is full professor of electrical engineering since 2000. He is a ICS (International Compumag Society) Member since 2008, an IEEE Member since 2012 and a ECS (Electrochemical Society) Member since 2014. Initially he centered his work on the analysis and design of large electromagnetic devices for the thermonuclear fusion research experiments Eta-Beta II and RFX, both built at Padua. For the latter he worked in and eventually led the Magntic System Group, responsible for the device’s major inductor systems (diameter up to 8 m, 50 kA, 200 kV). He later centered his interests in the area of numerical computation for electromagnetic and coupled problems. Since 13 years he is involved in the analysis, optimization and design of fuel cells, redox flow batteries and electrochemical storage devices, including modelling, experimental investigation, and parameters/performance identification. He is also widely interested in history of technology and science. His scientific production of over 200 items includes papers on journals and conference proceedings (over 110 indexed in Scopus) and several textbooks. He chairs the Education & Profession Group of the AEIT-ASTRI Italian Electrical Engineers Institution. He is the official representative of the University of Padua in N.ERGHY, the European Union association representing the universities and research institution in the Fuel Cell and Hydrogen Joint Technology Initiative (FCH JTI). He is a columnist and editorial board member of the IEEE Industrial Electronics Magazine.

Prof. Liserre

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Kolloquiumsvortrag, Prof. Massimo Guarnieri, University Padua (Italien) / am 24.04.2017

24.04.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Vanadium Redox Flow Batteries: Potentials and Challenges of an Emerging Storage Technology.

Abstract:  Energy storage is expected to expand its importance the next future, in order to provide increasing services, both mobile and stationary. Depending on their kind, rated powers vary from a few kilowatts (excluding portable electronics) to some gigawatts, with operating times ranging from fractions of a second to several hours and response times from milliseconds to some minutes. Electrochemical storage technologies are by far the most versatile form of energy storage to face this vast rising demand, and a huge market is soaring. Recent techno-financial analyses have forecasted investments exceeding US$10 billion/year on energy storage technologies by 2020.

The most enticing forms of electrochemical storage should allow to separated power and energy rating, in order to tailor discharge duration at will and the most promising solution for doing so at a reasonably high round-trip efficiency and at a high cycle life are flow batteries. For this reason, several major laboratories around the world are intensively researching them.

My talk will present the main feature of the most developed chemistry of flow battery, namely Vanadium Redox Flow Battery. An overview will be delivered on how they work, what are their architectures, needed ancillary technology, including power electronic interfaces, and possible applications, from small domestic end-user to smart-grid substations. The strengths, weaknesses and challenges of vanadium redox flow batteries will be highlights. A particular reference will be given to the research programs on VRFBs on-going at University of Padua, both experimental and numerical, aiming at taking them to full commercial success.

CV

Massimo Guarnieri joined the CNR (Italian National Council of Researches) in 1882 and the University of Padua in 1983, where he is full professor of electrical engineering since 2000. He is a ICS (International Compumag Society) Member since 2008, an IEEE Member since 2012 and a ECS (Electrochemical Society) Member since 2014. Initially he centered his work on the analysis and design of large electromagnetic devices for the thermonuclear fusion research experiments Eta-Beta II and RFX, both built at Padua. For the latter he worked in and eventually led the Magntic System Group, responsible for the device’s major inductor systems (diameter up to 8 m, 50 kA, 200 kV). He later centered his interests in the area of numerical computation for electromagnetic and coupled problems. Since 13 years he is involved in the analysis, optimization and design of fuel cells, redox flow batteries and electrochemical storage devices, including modelling, experimental investigation, and parameters/performance identification. He is also widely interested in history of technology and science. His scientific production of over 200 items includes papers on journals and conference proceedings (over 110 indexed in Scopus) and several textbooks. He chairs the Education & Profession Group of the AEIT-ASTRI Italian Electrical Engineers Institution. He is the official representative of the University of Padua in N.ERGHY, the European Union association representing the universities and research institution in the Fuel Cell and Hydrogen Joint Technology Initiative (FCH JTI). He is a columnist and editorial board member of the IEEE Industrial Electronics Magazine.

Prof. Liserre

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Kolloquiumsvortrag, M. Sc. Alexander Mäcker, Universität Paderborn / am 21.04.2017

21.04.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Non-Clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup Times

Abstract:

Consider a problem in which $n$ jobs that are classified into $k$ types arrive over time at their release times and are to be scheduled on a single machine so as to minimize the maximum flow time. The machine requires a setup taking $s$ time units whenever it switches from processing jobs of one type to jobs of a different type. We consider the problem as an online problem where each job is only known to the scheduler as soon as it arrives and where the processing time of a job only becomes known upon its completion (non-clairvoyance). We analyze a simple modification of the FIFO strategy and show the competitiveness to be $\Theta(\sqrt{n})$, which is optimal for ``greedy-like'' algorithms. We will then also consider a smoothed analysis of the competitiveness. The smoothed competitiveness turns out to only be $O(\varepsilon^{-2} \log^2 n)$ when processing times $p_j$ are independently perturbed by adding a random value uniformly drawn from $[-\varepsilon p_j, \varepsilon p_j]$, $0 < \varepsilon < 1$. The talk is based on joint work with Manuel Malatyali and Sören Riechers.

Prof. Jansen

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Kolloquiumsvortrag, M. Sc. Alexander Mäcker, Universität Paderborn / am 21.04.2017

21.04.2017 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Non-Clairvoyant Scheduling to Minimize Max Flow Time on a Machine with Setup Times

Abstract:

Consider a problem in which $n$ jobs that are classified into $k$ types arrive over time at their release times and are to be scheduled on a single machine so as to minimize the maximum flow time. The machine requires a setup taking $s$ time units whenever it switches from processing jobs of one type to jobs of a different type. We consider the problem as an online problem where each job is only known to the scheduler as soon as it arrives and where the processing time of a job only becomes known upon its completion (non-clairvoyance). We analyze a simple modification of the FIFO strategy and show the competitiveness to be $\Theta(\sqrt{n})$, which is optimal for ``greedy-like'' algorithms. We will then also consider a smoothed analysis of the competitiveness. The smoothed competitiveness turns out to only be $O(\varepsilon^{-2} \log^2 n)$ when processing times $p_j$ are independently perturbed by adding a random value uniformly drawn from $[-\varepsilon p_j, \varepsilon p_j]$, $0 < \varepsilon < 1$. The talk is based on joint work with Manuel Malatyali and Sören Riechers.

Prof. Jansen

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Kolloquiumsvortrag, Dipl.-Ing. Ingo Schalk-Schupp, Forschungslabor Nuance Communication / am 10.04.2017

10.04.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Nonlinear Echo Suppression

Abstract: This presentation provides a short overview concerning acoustic echo cancellation and acoustic echo suppression methods followed by a more in-depth discussion of new methods dealing with Hammerstein-type nonlinear distortions.

The Hammerstein system is divided into a linear and a parallel nonlinear part by an alternative way to define of the linear one. The implications of this separation definition and its relation to linear acoustic echo cancellation are illuminated.

Based on this approach, and assuming a converged linear echo canceller, a suppression approach for nonlinearly distorted acoustic echo signal components is introduced, the essential component of which is the nonlinear echo power spectral density estimation, which depends on one unknown real scalar parameter.

Subsequently, an identification algorithm for said parameter is presented, which results in a usable nonlinear echo suppressor still under the assumption of a converged linear echo canceller. Moreover, a generic comprehensive evaluation method for suppressor-type algorithms is advertised.

Finally, the challenge of concurrently adaptive linear echo canceller and nonlinear echo suppressor is analyzed and a solution for a full system is presented. After listening to several audio examples, the audience is invited to discuss the presentation’s contents.

Short biography

Ingo Schalk-Schupp studied systems engineering and technical cybernetics at Otto von Guericke University in Magdeburg, Germany. He graduated as a diploma engineer (Diplomingenieur) in 2012 with a diploma thesis titled “Speech Signal Enhancement in Automotive Environments” composed at Nuance Communications in Ulm, Germany. The thesis comprised two patent applications and was granted the best thesis award by the “Magdeburger Kybernetiker e.V.” Since 2012, he has been a PhD student with Nuance in Ulm and is supervised by Professor Andreas Wendemuth, Chair of Cognitive Systems at Otto von Guericke University Magdeburg. This presentation reflects the author’s findings from his PhD research.

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Kolloquiumsvortrag, Dipl.-Ing. Ingo Schalk-Schupp, Forschungslabor Nuance Communication / am 10.04.2017

10.04.2017 von 17:15 bis 18:45

Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel

Titel: Nonlinear Echo Suppression

Abstract: This presentation provides a short overview concerning acoustic echo cancellation and acoustic echo suppression methods followed by a more in-depth discussion of new methods dealing with Hammerstein-type nonlinear distortions.

The Hammerstein system is divided into a linear and a parallel nonlinear part by an alternative way to define of the linear one. The implications of this separation definition and its relation to linear acoustic echo cancellation are illuminated.

Based on this approach, and assuming a converged linear echo canceller, a suppression approach for nonlinearly distorted acoustic echo signal components is introduced, the essential component of which is the nonlinear echo power spectral density estimation, which depends on one unknown real scalar parameter.

Subsequently, an identification algorithm for said parameter is presented, which results in a usable nonlinear echo suppressor still under the assumption of a converged linear echo canceller. Moreover, a generic comprehensive evaluation method for suppressor-type algorithms is advertised.

Finally, the challenge of concurrently adaptive linear echo canceller and nonlinear echo suppressor is analyzed and a solution for a full system is presented. After listening to several audio examples, the audience is invited to discuss the presentation’s contents.

Short biography

Ingo Schalk-Schupp studied systems engineering and technical cybernetics at Otto von Guericke University in Magdeburg, Germany. He graduated as a diploma engineer (Diplomingenieur) in 2012 with a diploma thesis titled “Speech Signal Enhancement in Automotive Environments” composed at Nuance Communications in Ulm, Germany. The thesis comprised two patent applications and was granted the best thesis award by the “Magdeburger Kybernetiker e.V.” Since 2012, he has been a PhD student with Nuance in Ulm and is supervised by Professor Andreas Wendemuth, Chair of Cognitive Systems at Otto von Guericke University Magdeburg. This presentation reflects the author’s findings from his PhD research.

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Sonderkolloquium, Dr. Chidambaram Amalai, ETH Zürich / am 10.04.2017

10.04.2017 von 15:00 bis 16:30

Ludewig-Meyn-Str. 2. Raum Ü2/K (LMS2, R. Ü2/K)

Titel: Algorithmic Advances in Allocation and Scheduling

Abstract: We study the restricted case of Scheduling on Unrelated Parallel
Machines. In this problem, we are given a set of jobs J with processing
times p_j and each job may be scheduled only on some subset of machines
S_j. The goal is to find an assignment of jobs to machines to minimize
the time by which all jobs can be processed. In a seminal paper,
Lenstra, Shmoys, and Tardos designed an elegant 2-approximation for the
problem in 1987. The question of whether approximation algorithms with
better guarantees exist for this classic scheduling problem has since
remained a source of mystery.

In recent years, with the improvement of our understanding of
Configuration LPs, it now appears an attainable goal to design such an
algorithm. Our main contribution is to make progress towards this goal.
When the processing times of jobs are either 1 or epsilon < 1, we design
an approximation algorithm whose guarantee tends to 1+sqrt(3)/2 =
1.8660254, for the interesting cases when epsilon approaches 0. This
improves on the 2 - epsilon_0 guarantee recently obtained by
Chakrabarty, Khanna, and Li for some constant epsilon_0 > 0.

 

Prof. Jansen

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Sonderkolloquium, Dr. Chidambaram Amalai, ETH Zürich / am 10.04.2017

10.04.2017 von 15:00 bis 16:30

Ludewig-Meyn-Str. 2. Raum Ü2/K (LMS2, R. Ü2/K)

Titel: Algorithmic Advances in Allocation and Scheduling

Abstract: We study the restricted case of Scheduling on Unrelated Parallel
Machines. In this problem, we are given a set of jobs J with processing
times p_j and each job may be scheduled only on some subset of machines
S_j. The goal is to find an assignment of jobs to machines to minimize
the time by which all jobs can be processed. In a seminal paper,
Lenstra, Shmoys, and Tardos designed an elegant 2-approximation for the
problem in 1987. The question of whether approximation algorithms with
better guarantees exist for this classic scheduling problem has since
remained a source of mystery.

In recent years, with the improvement of our understanding of
Configuration LPs, it now appears an attainable goal to design such an
algorithm. Our main contribution is to make progress towards this goal.
When the processing times of jobs are either 1 or epsilon < 1, we design
an approximation algorithm whose guarantee tends to 1+sqrt(3)/2 =
1.8660254, for the interesting cases when epsilon approaches 0. This
improves on the 2 - epsilon_0 guarantee recently obtained by
Chakrabarty, Khanna, and Li for some constant epsilon_0 > 0.

 

Prof. Jansen

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Sonderkolloquium, Prof. Gerold Jäger, Universität Umeâ, Schweden / am 09.03.2017

09.03.2017 von 11:00 bis 12:30

Institut für Informatik, Christian-Albrechts-Platz 4, Raum 910 (CAP 4)

Titel: Optimale Strategien für die Black-Peg-Variante des Statischen Masterminds und des Statischen AB-Games

Abstract: Mastermind ist ein Logikspiel für zwei Personen, das im Jahre 1970 erfunden wurde und sich seit zu einem populären Gesellschaftsspiel entwickelt hat, das über 50 Millionen Mal verkauft wurde. Die beiden am Spiel beteiligten Spieler werden als Codemaker und Codebreaker bezeichnet. Der Codemaker legt zu Beginn des Spiels einen vierstelligen Farb-Code fest, der aus sechs Farben ausgewählt wird. Der Codebreaker versucht, diesen Code zu erraten, indem er einen gleichartigen Farb-Code als Frage verwendet und vom Codemaker eine Antwort erhält, wie nahe seine Frage am zu erratenden Farb-Code ist. Für jeden Stift, der sowohl in Farbe als auch in Position richtig ist, gibt der Codemaker einen schwarzen Stift in der Antwort und für jeden Stift, der nur in der Farbe richtig ist, einen weißen Stift. Mit Hilfe dieser Antwort kann er weitere Fragen stellen, die auf dasselbe Weise beantwortet werden, und dies geschieht solange, bis der Codebreaker den Farb-Code erraten hat. Eine natürliche Erweiterung ist es, statt einenm vierstelligen Farb-Code einen p-stelligen mit beliebigem p zu erlauben und statt 6 Farben c Farben mit beliebigem c zu erlauben. Insbesondere in den letzten 10 Jahren hat sich Mastermind zu einem vielbeachteten Forschungsthema entwickelt. Im Jahre 2006 wurde gezeigt, dass Mastermind NP vollständig ist. Des Weiteren wurden Anwendungen von Mastermind in der Komplexitätstheorie, Bioinformatik und Kryptographie untersucht und es wurden Schranken und optimale Strategien für viele Mastermind-Varianten bewiesen, oft indem entweder konstantes p oder konstantes c betrachtet wurden. In diesem Vortrag betrachten wir eine Kombination von drei Mastermind-Varianten: 1. Das AB-Game, das sich von Mastermind unterscheidet, indem sowohl in dem Farb-Code als auch bei den Fragen die Stifte alle verschiedene Farben haben müssen. 2. Die Black-Peg-Variante, in der der Codemaker nur schwarze Stifte als Antwort gibt. 3. Statisches Mastermind, in dem der Codebreaker eine bestimmte Anzahl von Fragen gleich zu Beginn des Spieles gibt, dann alle Antworten erhält und schließlich nur noch einen weiteren Versuch hat, den richtigen Farb-Code zu erraten.
Goddard hat im Jahre 2003 optimale Strategien für das originale Statische Mastermind vorgestellt, und zwar für den Fall von p=2, p=3, p=4 Stiften. In diesem Vortrag wird eine Strategie für die Black-Peg Variante des Statischen Mastermind mit p=2 Stiften vorgestellt und deren Zulässigkeit und Optimalität bewiesen. Des Weiteren werden Strategien für p=3, c=2, c=3 vorgestellt, deren Optimalitätsbeweis ein offenes Problem darstellt. Schließlich 9 weitere Paare (p,c) presentiert, deren Zulässigkeit und Optimalität mit Hilfe eines Computerprogramms gezeigt werden konnte. Am Ende des Vortrags wird über Work-in-Progress berichtet, und zwar über zulässige und optimale Strategien für die Black-Peg-Version des AB-Games. Insbesondere geht es um die Fälle von p=2 Stiften und p=c Stiften. Der letzte Fall ist besonders interessant, aber auch anspruchsvoll, da der Farb-Code und die Fragen Permutationen entsprechen.

Prof. Srivastav

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Sonderkolloquium, Prof. Gerold Jäger, Universität Umeâ, Schweden / am 09.03.2017

09.03.2017 von 11:00 bis 12:30

Institut für Informatik, Christian-Albrechts-Platz 4, Raum 910 (CAP 4)

Titel: Optimale Strategien für die Black-Peg-Variante des Statischen Masterminds und des Statischen AB-Games

Abstract: Mastermind ist ein Logikspiel für zwei Personen, das im Jahre 1970 erfunden wurde und sich seit zu einem populären Gesellschaftsspiel entwickelt hat, das über 50 Millionen Mal verkauft wurde. Die beiden am Spiel beteiligten Spieler werden als Codemaker und Codebreaker bezeichnet. Der Codemaker legt zu Beginn des Spiels einen vierstelligen Farb-Code fest, der aus sechs Farben ausgewählt wird. Der Codebreaker versucht, diesen Code zu erraten, indem er einen gleichartigen Farb-Code als Frage verwendet und vom Codemaker eine Antwort erhält, wie nahe seine Frage am zu erratenden Farb-Code ist. Für jeden Stift, der sowohl in Farbe als auch in Position richtig ist, gibt der Codemaker einen schwarzen Stift in der Antwort und für jeden Stift, der nur in der Farbe richtig ist, einen weißen Stift. Mit Hilfe dieser Antwort kann er weitere Fragen stellen, die auf dasselbe Weise beantwortet werden, und dies geschieht solange, bis der Codebreaker den Farb-Code erraten hat. Eine natürliche Erweiterung ist es, statt einenm vierstelligen Farb-Code einen p-stelligen mit beliebigem p zu erlauben und statt 6 Farben c Farben mit beliebigem c zu erlauben. Insbesondere in den letzten 10 Jahren hat sich Mastermind zu einem vielbeachteten Forschungsthema entwickelt. Im Jahre 2006 wurde gezeigt, dass Mastermind NP vollständig ist. Des Weiteren wurden Anwendungen von Mastermind in der Komplexitätstheorie, Bioinformatik und Kryptographie untersucht und es wurden Schranken und optimale Strategien für viele Mastermind-Varianten bewiesen, oft indem entweder konstantes p oder konstantes c betrachtet wurden. In diesem Vortrag betrachten wir eine Kombination von drei Mastermind-Varianten: 1. Das AB-Game, das sich von Mastermind unterscheidet, indem sowohl in dem Farb-Code als auch bei den Fragen die Stifte alle verschiedene Farben haben müssen. 2. Die Black-Peg-Variante, in der der Codemaker nur schwarze Stifte als Antwort gibt. 3. Statisches Mastermind, in dem der Codebreaker eine bestimmte Anzahl von Fragen gleich zu Beginn des Spieles gibt, dann alle Antworten erhält und schließlich nur noch einen weiteren Versuch hat, den richtigen Farb-Code zu erraten.
Goddard hat im Jahre 2003 optimale Strategien für das originale Statische Mastermind vorgestellt, und zwar für den Fall von p=2, p=3, p=4 Stiften. In diesem Vortrag wird eine Strategie für die Black-Peg Variante des Statischen Mastermind mit p=2 Stiften vorgestellt und deren Zulässigkeit und Optimalität bewiesen. Des Weiteren werden Strategien für p=3, c=2, c=3 vorgestellt, deren Optimalitätsbeweis ein offenes Problem darstellt. Schließlich 9 weitere Paare (p,c) presentiert, deren Zulässigkeit und Optimalität mit Hilfe eines Computerprogramms gezeigt werden konnte. Am Ende des Vortrags wird über Work-in-Progress berichtet, und zwar über zulässige und optimale Strategien für die Black-Peg-Version des AB-Games. Insbesondere geht es um die Fälle von p=2 Stiften und p=c Stiften. Der letzte Fall ist besonders interessant, aber auch anspruchsvoll, da der Farb-Code und die Fragen Permutationen entsprechen.

Prof. Srivastav

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Sonderkolloquium Prof. Concari, University of Parma / am 21.02.2017

21.02.2017 von 15:00 bis 16:30

Technische Fakultät, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Fault Diagnosis of Electrical Machines

Abstract: The fault diagnosis of electrical machines has been the subject of intensive research for several decades. Being able to detect or predict incipient faults before they impair the ability of the machines to function properly is a very welcome feature in industrial environments, where unscheduled downtime can cause production and financial loss.

Electrical machine faults include electrical stator faults, electrical rotor faults, eccentricity, bearing faults. Diagnostic techniques for the detection of such faults in electrical machines are reviewed, and their effectivity is assessed in different operating conditions, including closed-loop inverter-fed operation. Furthermore, the impact of wide-bandgap devices is discussed and prognostic techniques are reviewed, with particular focus on aerospace applications.

Prof. Liserre

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Sonderkolloquium Prof. Concari, University of Parma / am 21.02.2017

21.02.2017 von 15:00 bis 16:30

Technische Fakultät, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Fault Diagnosis of Electrical Machines

Abstract: The fault diagnosis of electrical machines has been the subject of intensive research for several decades. Being able to detect or predict incipient faults before they impair the ability of the machines to function properly is a very welcome feature in industrial environments, where unscheduled downtime can cause production and financial loss.

Electrical machine faults include electrical stator faults, electrical rotor faults, eccentricity, bearing faults. Diagnostic techniques for the detection of such faults in electrical machines are reviewed, and their effectivity is assessed in different operating conditions, including closed-loop inverter-fed operation. Furthermore, the impact of wide-bandgap devices is discussed and prognostic techniques are reviewed, with particular focus on aerospace applications.

Prof. Liserre

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Kolloquiumsvortrag, Dr. Pio Lombardi, Otto v. Guericke University, Magdeburg / am 19.12.2016

19.12.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Multi-Energy Systems Applied to Smart Factories

Abstract: The use of renewable energy sources (RES) will be the backbone of future energy systems. The European Union intends to produce up to 55% of the gross energy consumed from RES by 2050. Integrating these intermittent energy sources in the grid represents a huge challenge. At the end of 2015, over 60GW of intermittent (wind and solar) RES were in operation in Germany. Together with biomass, this covers around 30% of the total electricity consumption. Germany invested over € 1 billion in 2015 to integrate RES in the electrical grid, most of the money going toward redispatching. Since system operators are frequently unable to integrate the power generated by RES in the grid, operators of RES power plants have to switch them off. Multi-energy systems (MES) provide a means to integrate volatile RES in the energy system (electricity, gas and heat). MES can convert electricity into other forms of energy such gas and heat and vice versa. The heart of a MES is an energy management system (EMS) that optimally controls the power generated, consumed, stored and converted. An MES designed for smart factories has been implemented and is being refined at the Fraunhofer Institute IFF in Magdeburg. The underlying idea is to maximize the responsiveness of industrial processes to the power generated by RES in order to have a manufacturing process with near-zero carbon emissions.

The aim of the talk is to present and examine the preliminary results of the Fraunhofer Institute IFF Magdeburg’s MES test platform for smart grids.

Curriculum Vitae

Pio Lombardi studied mechanical engineering at the Politecnico di Bari, Italy. He graduated in 2006 at the same university with the degree M.Sc. He joined the Chair of Electric Power Networks and Renewable Energy Sources at the Otto-von-Guericke University Magdeburg, Germany as a research engineer in 2006. At the same university he received his PhD. In 2011 he joined the Process and Plant Engineering of Fraunhofer Institute for Factory Operation and Automation IFF. His primary field of interest includes modeling, simulation and optimization of multi-energy systems.  Since 2009 is Dr. Lombardi lecturer in “Power System Economics and special topics” at Otto von Guericke University Magdeburg (Germany) and in “ Renewable Energy Systems” at Technical University of Wroclaw (Poland) . He is expert member of the Cigrè SC C6 on “Distribution Systems and Dispersed Generators”. He was secretary of the Cigré Working Group C6.15 on “Electric Energy Storage Systems”, currently he is a member of Cigré Working Group C6.22 on “Microgrid Evolution Roadmap” and C6.30 “The Impact of Battery Energy Storage Systems on Distribution Networks”.

Prof. Marco Liserre

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Kolloquiumsvortrag, Dr. Peter Zaspel, Universität Heidelberg / am 09.12.2016

09.12.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: H-matrices on many-core hardware with applications in parametric PDEs

Abstract:

Hierarchical matrices approximate specific types of dense matrices,
e.g., from discretized integral equations, kernel-based approximation
and Gaussian process regression, leading to log-linear time complexity
in dense matrix-vector products. To be able to solve large-scale
applications, H-matrix algorithms have to be parallelized. A special
kind of parallel hardware are many-core processors, e.g. graphics
processing units (GPUs). The parallelization of H-matrices on many-core
processors is difficult due to the complex nature of the underlying
algorithms that need to be mapped to rather simple parallel operations.

We are interested to use these many-core processors for the full
H-matrix construction and application process. A motivation for this
interest lies in the well-known claim that future standard processors
will evolve towards many-core hardware, anyway. In order to be prepared
for this development, we want to discuss many-core parallel formulations
of classical H-matrix algorithms and adaptive cross approximations.

In the presentation, the use of H-matrices is motivated by the model
application of kernel-based approximation for the solution of parametric
PDEs, e.g. PDEs with stochastic coefficients. The main part of the talk
will be dedicated to the challenges of H-matrix parallelizations on
many-core hardware with the specific model hardware of GPUs. We propose
a set of parallelization strategies which overcome most of these
challenges. Benchmarks of our implementation are used to explain the
effect of different parallel formulations of the algorithms.

Prof. Steffen Börm

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Sonderkolloquium Greg P. Carman (IEEE Magnetics Distinguished Lecturer) / am 08.12.2016

Sonderkolloquium Greg P. Carman (IEEE Magnetics Distinguished Lecturer) / am 08.12.2016

Sonderkolloquium Prof. J.I. Leon / 07.12.2016

07.12.2016 von 10:00 bis 11:30

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: Geb. D, "Aquarium"

Titel: The Essential Role and the Continuous Evolution of Modulation Techniques for Voltage-Source Inverters in the Past, Present, and Future Power Electronics

Abstract: The cost reduction of power electronic devices, the increase in their reliability, efficiency and power capability, lower development times, together with more demanding application requirements, have driven the development of several new inverter topologies recently introduced in industry, particularly medium-voltage converters. New more complex inverter topologies and new application fields come along with additional control challenges, such as: voltage imbalances, power quality issues, higher efficiency needs and fault tolerant operation, which necessarily requires the parallel development of modulation schemes.
Therefore, recently there have been significant advances in the field of modulation of dc/ac converters, which conceptually has been dominated during the last several decades almost exclusively by classic pulse width modulation methods. This talk aims to concentrate and discuss the latest developments on this exciting technology, to provide insight on where the state-of-the-art stands today, and analyze the trends and challenges driving its future.

Prof. Marco Liserre

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Sonderkolloquium Prof. J.I. Leon / 07.12.2016

07.12.2016 von 10:00 bis 11:30

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: Geb. D, "Aquarium"

Titel: The Essential Role and the Continuous Evolution of Modulation Techniques for Voltage-Source Inverters in the Past, Present, and Future Power Electronics

Abstract: The cost reduction of power electronic devices, the increase in their reliability, efficiency and power capability, lower development times, together with more demanding application requirements, have driven the development of several new inverter topologies recently introduced in industry, particularly medium-voltage converters. New more complex inverter topologies and new application fields come along with additional control challenges, such as: voltage imbalances, power quality issues, higher efficiency needs and fault tolerant operation, which necessarily requires the parallel development of modulation schemes.
Therefore, recently there have been significant advances in the field of modulation of dc/ac converters, which conceptually has been dominated during the last several decades almost exclusively by classic pulse width modulation methods. This talk aims to concentrate and discuss the latest developments on this exciting technology, to provide insight on where the state-of-the-art stands today, and analyze the trends and challenges driving its future.

Prof. Marco Liserre

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Sonderkolloquium Dr. Akihiko Sugiyama / 06.12.2016

06.12.2016 von 17:15 bis 18:45 – Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: Geb. D, "Aquarium"

Sonderkolloquium Dr. Akihiko Sugiyama / 06.12.2016

06.12.2016 von 17:15 bis 18:45 – Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: Geb. D, "Aquarium"

Kolloquiumsvortrag, Jochen Speck, Karlsruher Institut für Technologie / am 02.12.2016

02.12.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Theory and Engineering of Scheduling Parallel Jobs

Abstract: Dieser Vortrag gibt einen kurzen Überblick über meine Arbeit zum Scheduling paralleler Jobs auf aktuellen und zukünftigen Maschinen.
Neben meinem generellen Ansatz werde ich zwei im Rahmen dieser Arbeit entwickelte Verfahren vorstellen:
1. Das Scheduling von malleablen Jobs auf Maschinen mit variabler Arbeitsfrequenz mit dem Ziel, den Energieverbrauch zu minimieren.
2. Einen anwendungsinternen Scheduler zur Verbesserung der Cache/Speicher-Effizienz der LU-Zerlegung.

Prof. Klaus Jansen

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Kolloquiumsvortrag, Prof. Tamas Kerekes, Aalborg University Denmark / am 28.11.2016

28.11.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Problem Based Learning – the Aalborg way

Abstract: Problem Based Learning (PBL) has been successfully applied at Aalborg University (AAU) since it was established in 1974. PBL is not only about rote learning. Every semester students work in a group with fellow students having different academic strengths and weaknesses, combining their common knowledge to solve a problem. The work should end in the submission of a semester report, describing the main problem, the objectives and the methodology how the problem was solved and how successful they were in achieving the objectives, detailing the results, including simulation, modelling and laboratory experiments. Group members will need to collaborate with each other, define and divide the tasks for achieving the goals that they set in the beginning of the project. This way the group work will have an academic and social dimension at the same time, by which the students will learn how to work together with other people, a quality which is very important on the labor market/in industry. PBL gives the opportunity to put theoretical knowledge into practice. By working with “real-life” problems, the students will not only gain professional experience, but they will also make good contacts, that can be used in the future in case of job applications. Furthermore, these “real-life” problems come from industrial partners/companies, therefore students will work with problems related to leading edge research, and their results/findings might be included in tomorrow’s commercial products.

Prof. Liserre

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Sonderkolloquium Prof. Joachim Holtz, Technical University Braunschweig / 25.11.2016

25.11.2016 von 12:00 bis 13:00

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: Geb. B Raum 101

Titel: Predictive Current Control

Abstract: Predictive Current Control – When to use?

Switching losses contribute the major portion to the total losses in medium voltage drives. Operation at extremely low switching frequency is therefore mandatory. Low harmonic current distortion can be nevertheless maintained when predictive current control is used.

Predictive current control is currently attracting the interest of many researchers. Even specific conferences are being organized on this novel topic. The predictive algorithm directly generates the firing pulses of the inverter, thus eliminating a pulsewidth modulator. A preset magnitude of the current error is permitted, defined as the magnitude difference between reference and actual current space vectors. Inverter gate pulses are generated such as to maximize the time differences between any two switching instants. This minimizes the switching frequency, and thus the switching losses. Harmonic current distortion is held at a predetemined value.

A gate pulse is generated whenever a predefined current error is exceeded. That error is computed as the difference between reference and actual current space vector. The next switching state is then determined such that maximum time elapses until the error vector exceeds its limit again. This minimizes the switching frequency and also the switching losses. Overmodulation and a smooth transition to full-wave operation produces maximum inverter output voltage. The error vector is represented here in a rotor field oriented coordinate system and different error magnitudes are permitted in the respective axes. 

About the Speaker

Joachim Holtz graduated in 1967 and received the Ph.D. degree in 1969 from the Technical University Braunschweig, Germany.

In 1969 he became Associate Professor and, and in 1971 Full Professor and Head of the Control Engineering Laboratory, Indian Institute of Technology in Madras, India. He joined the Siemens Research Laboratories in Erlangen, Germany in 1972. From 1976 to 1998, he was Professor and Head of the Electrical Machines and Drives Laboratory, Wuppertal University, Germany. He is presently Professor Emeritus and a Consultant.

His publications include 2 invited papers in the PROCEEDINGS OF THE IEEE, 17 invited papers in IEEE Journals, and 27 single-authored IEEE Journal papers. He is the recipient of 17 Prize Paper Awards, a coauthor of seven books and holds 33 patents.

Dr. Holtz is the recipient of the IEEE Industrial Electronics Society Dr. Eugene Mittelmann Achievement Award, the IEEE Industrial Applications Society Outstanding Achievement Award, the IEEE Power Electronics Society William E. Newell Field Award, the IEEE Third Millennium Medal, the Anthony J. Hornfeck Service Award, and the IEEE Lamme Gold Medal. He is a Life Fellow of the IEEE.

Dr. Holtz is Past Editor-in-Chief of the IEEE Transactions on Industrial Electronics, Distinguished Lecturer of the IEEE Industrial Applications Society and IEEE Industrial Electronics Society.

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Sonderkolloquium Prof. Joachim Holtz, Technical University Braunschweig / 25.11.2016

25.11.2016 von 12:00 bis 13:00

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: Geb. B Raum 101

Titel: Predictive Current Control

Abstract: Predictive Current Control – When to use?

Switching losses contribute the major portion to the total losses in medium voltage drives. Operation at extremely low switching frequency is therefore mandatory. Low harmonic current distortion can be nevertheless maintained when predictive current control is used.

Predictive current control is currently attracting the interest of many researchers. Even specific conferences are being organized on this novel topic. The predictive algorithm directly generates the firing pulses of the inverter, thus eliminating a pulsewidth modulator. A preset magnitude of the current error is permitted, defined as the magnitude difference between reference and actual current space vectors. Inverter gate pulses are generated such as to maximize the time differences between any two switching instants. This minimizes the switching frequency, and thus the switching losses. Harmonic current distortion is held at a predetemined value.

A gate pulse is generated whenever a predefined current error is exceeded. That error is computed as the difference between reference and actual current space vector. The next switching state is then determined such that maximum time elapses until the error vector exceeds its limit again. This minimizes the switching frequency and also the switching losses. Overmodulation and a smooth transition to full-wave operation produces maximum inverter output voltage. The error vector is represented here in a rotor field oriented coordinate system and different error magnitudes are permitted in the respective axes. 

About the Speaker

Joachim Holtz graduated in 1967 and received the Ph.D. degree in 1969 from the Technical University Braunschweig, Germany.

In 1969 he became Associate Professor and, and in 1971 Full Professor and Head of the Control Engineering Laboratory, Indian Institute of Technology in Madras, India. He joined the Siemens Research Laboratories in Erlangen, Germany in 1972. From 1976 to 1998, he was Professor and Head of the Electrical Machines and Drives Laboratory, Wuppertal University, Germany. He is presently Professor Emeritus and a Consultant.

His publications include 2 invited papers in the PROCEEDINGS OF THE IEEE, 17 invited papers in IEEE Journals, and 27 single-authored IEEE Journal papers. He is the recipient of 17 Prize Paper Awards, a coauthor of seven books and holds 33 patents.

Dr. Holtz is the recipient of the IEEE Industrial Electronics Society Dr. Eugene Mittelmann Achievement Award, the IEEE Industrial Applications Society Outstanding Achievement Award, the IEEE Power Electronics Society William E. Newell Field Award, the IEEE Third Millennium Medal, the Anthony J. Hornfeck Service Award, and the IEEE Lamme Gold Medal. He is a Life Fellow of the IEEE.

Dr. Holtz is Past Editor-in-Chief of the IEEE Transactions on Industrial Electronics, Distinguished Lecturer of the IEEE Industrial Applications Society and IEEE Industrial Electronics Society.

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Kolloquiumsvortrag am 21.11.2016 / Dr. Christoph Lange, Deutsche Telekom AG, Telekom Innovation Laboratories

21.11.2016 von 17:15 bis 18:45

Technische Fakultät, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Energiebedarf beim Betrieb von Telekommunikationsnetzen

 

Abstract: Telekommunikationsnetze als weit verzweigte technische Infrastrukturen mit einer Vielzahl aktiver Komponenten weisen einen signifikanten Energiebedarf auf, der sich in unterschiedliche Energieformen unterteilen lässt. Mit Fokus auf die zum Netzbetrieb notwendige Elektroenergie wird analysiert, welche Energieanteile in welchen Netzsegmenten benötigt werden. Anschließend werden Möglichkeiten zur Verbesserung der Energieeffizienz beim Betrieb von Telekommunikationsnetzen diskutiert und aktuelle Entwicklungstrends in Telekommunikationsnetzen und deren energie-relevante Implikationen aufgezeigt.

Christoph Lange absolvierte an der Universität Rostock ein Studium der Elektrotechnik (Spezialisierung Nachrichtentechnik) mit dem Abschluss als Diplom-Ingenieur im Jahr 1998 und schloss im Jahr 2003 eine Promotion auf dem Gebiet der Nachrichtenübertragungstechnik als Dr.-Ing. an derselben Universität ab. Derzeit ist er bei der Deutschen Telekom AG, Telekom Innovation Laboratories, in Berlin beschäftigt. Seine Arbeitsgebiete umfassen schwerpunktmäßig Breitbandzugangsnetze und die Energieeffizienz von Telekommunikationsnetzen.

 

Prof. Pachnicke

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Kolloquiumsvortrag, Prof. Giuseppe Buja, IEEE Fellow, University of Padova, Italien / am 14.11.2016

14.11.2016 von 17:15 bis 18:45

Technische Fakultät, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Wireless Power Transfer systems for static and dynamic charging of electric vehicles

Abstract: The talk will deal with the research activities carried out at the Department of Industrial Electronics of the University of Padova, Italy, on the WPT systems of inductive type. After an overview on WPT, the static WPT systems are introduced. The main resonant topologies are illustrated and their efficiency vs. loads of different type (resistance or DC-DC chopper) is discussed. Then, the design of a WPT system for charging the batteries of a minicar is given, with details on the design of the coils and the power supply of the system. Experimental results obtained from a laboratory prototype are shown, reporting waveforms and efficiency curves.
The ongoing studies on the dynamic WPT systems are then presented. After a review of the specific problems posed by the dynamic WPT, the lumped track structure is considered. Suitable solutions for the power supply, the track segmentation, the coil geometries, and the compensation networks are went through. Finally, an under-development project of a dynamic WPT system for charging the batteries of a demonstration car is given.

Prof. Liserre

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Kolloquiumsvortrag, Antrittsvorlesung Prof. Stephan Pachnicke, Technische Fakultät, Nachrichtenübertragungstechnik / am 07.11.2016

07.11.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Optische Nachrichtenübertragungsnetze der nächsten Generation

Zusammenfassung: Zukünftige Datenübertragungsnetze müssen Schritt halten mit dem exponentiell ansteigenden Bandbreitenbedarf, der voraussichtlich auch auf längere Sicht mit einer Wachstumsrate von ca. 40-60% pro Jahr zunehmen wird. Die größten Wachstumstreiber sind hierbei die bandbreitenintensiven Multimedia-Dienste wie z.B. Video-on-Demand in HD-TV und 4K-Qualität und insbesondere auch der rasant steigende Datenverkehr in Mobilfunknetzen. Eine weitere Herausforderung stellen die immer weiter steigenden Datenraten dar, die von Maschinen generiert werden und in stetig wachsenden Rechenzentren verarbeitet werden müssen.

Nur optische Übertragungssysteme können diesen Anforderungen gerecht werden. In dem Vortrag werden Herausforderungen und Lösungsmöglichkeiten für die nächste Generation von optischen Netzen vorgestellt. Hierbei ist nicht nur die Skalierbarkeit der Übertragungskapazität im Auge zu behalten, sondern muss auch eine substantielle Verringerung der Kosten pro übertragenem Bit erreicht werden. Dafür werden neue Systemkonzepte präsentiert, die auf integriert-optischen Komponenten und innovativen Subsystemen basieren.

Prof. Stephan Pachnicke

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Kolloquiumsvortrag, Professor Chengbin Ma, University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University am 31.10.2016

31.10.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Modeling, Design, and Control of Megahertz Wireless Power Systems

Abstract: A high level of spatial freedom makes wireless power transfer (WPT) working at several megahertz (MHz) attractive for charging various electronic devices. However, the operation in the MHz frequency band presents technical challenges due to the potentially increased power losses, strong nonlinearities of the devices, and electromagnetic interference (EMI) problem. Both a circuit- and a system-level analyses are important to derive requirements for a high overall system performance such as efficiency and harmonics suppression. Besides, unavoidable uncertainties in a real WPT system require either a feedback mechanism or improved design to enhance the robustness. This presentation reviews the activities on MHz WPT conducted by our group, particularly at the modeling, design, and control aspects. First the challenges from the MHz WPT are summarized and explained. Then the feedback-based approaches are developed to actively improve the robustness of the WPT system when there are variations in the coil relative position and final load, the two major sources of uncertainties. The Class E power amplifier (PA) and rectifier are further introduced into the MHz WPT systems, which help to improve the efficiency thanks to the soft-switching properties of the PA and rectifier. They also make the analytical derivations possible that facilitate the optimization-based designs. Finally, the initial efforts on the multi-receiver MHz WPT systems are mentioned such as design of a current-mode Class E PA, analysis and compensation of cross coupling, and impedance matching under a varying loading condition. For details, please refer to our publications [LINK].

Professor Chengbin Ma
received the B.S.E.E. degree (Hons.) from East China University of Science and Technology, Shanghai, China, in 1997, and the M.S. and Ph.D. degrees in electrical engineering from The University of Tokyo, Tokyo, Japan, in 2001 and 2004, respectively. From 2004 to 2006, he was a R&D Researcher with the Servo Motor Laboratory, FANUC Ltd., Oshino-mura, Yamanashi Prefecture, Japan. Between 2006 and 2008, he was a Postdoctoral Researcher with the Department of Mechanical and Aeronautical Engineering, University of California, Davis.

He is now an Assistant Professor of electrical and computer engineering with the University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai and has a joint faculty appointment with School of Mechanical Engineering, Shanghai Jiao Tong University. His research interests include battery/energy management, wireless power transfer, mechatronic control, and applications in electric vehicles, microgrids, and smartgrids.

Dr. Ma is a member of The Institute of Electrical and Electronics Engineers and a vice chair of Energy Storage Technical Committee, IEEE Industrial Electronics Society (email: chbma@sjtu.edu.cn; web: http://umji.sjtu.edu.cn/lab/dsc/).

 

Prof. Marco Liserre

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Doppelkolloquium, Prof. C. V. Lakshmi, Computer Science Dayalbagh Educational Institut, Agra, India / am 05.10.2016, 15:15 Uhr - 16:00 Uhr

05.10.2016 um 15:15 bis 17.10.2016 um 16:00

Institut für Informatik, Vorbau Ludewig-Meyn-Straße 2, 24118 Kiel, Raum Ü2/K

Titel: A fast and robust many fonts printed Optical Character Recognition system for Indian Scripts

Abstract: Making machines “read” text printed or handwritten on paper has been a long cherished goal in Computer Science. Considerable success has been achieved for scripts like Roman script that is quite simple and consists of very few symbols.
This talk describes the design and development of an Optical Character Recognition system for printed many-font Indian scripts. The system takes an image of printed text in Devanagari (Hindi, dominant language in North India) or Telugu (a prominent South Indian Language) as an input. It performs a full OCR and provides output that can be directly taken into an editor. Indian scripts are classified into two classes – one class consists of scripts that are written with a prominent headline called Shirorekha and the other class consists of those scripts which do not have a shirorekha. In our work, Devanagari is taken as a representative of the first class and Telugu as a representative of the second class as specified above.
Indian scripts are extremely complicated due to the presence of a vast number of possible combinations of vowels and consonants which are written joined together to form what are called compound characters. The OCR problem becomes even more difficult when text is present in complicated layouts or on complicated backgrounds.
The OCR system designed and implemented is shown to provide excellent results for text images of Telugu and Devanagari. A large number of fonts are considered – 24 for Telugu and 25 for Devanagari and the results are excellent for all these fonts. This is the first reported attempt that works for such a large number of fonts for Indian scripts. Further the recognition rates are enhanced by judiciously implementing schemes for reducing the number of exemplars and the number of features to be stored in the databases. New types of features in transform domain are shown to give better results. The fact that the system works excellently for all these fonts on both Shirorekha-based script as well as non-Shirorekha based Indian script augurs well for the other Indian scripts.
The talk would highlight the main characteristics of Indian scripts and the challenges in development of OCR for them. It would then describe how these challenges are resolved in our work. Considerable emphasis would be laid on practical demonstration of the OCR system apart from explaining its internal structure and logic.

Prof. Anand Srivastav

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Doppelkolloquium, Prof. C. V. Lakshmi, Computer Science Dayalbagh Educational Institut, Agra, India / am 05.10.2016, 15:15 Uhr - 16:00 Uhr

05.10.2016 um 15:15 bis 17.10.2016 um 16:00

Institut für Informatik, Vorbau Ludewig-Meyn-Straße 2, 24118 Kiel, Raum Ü2/K

Titel: A fast and robust many fonts printed Optical Character Recognition system for Indian Scripts

Abstract: Making machines “read” text printed or handwritten on paper has been a long cherished goal in Computer Science. Considerable success has been achieved for scripts like Roman script that is quite simple and consists of very few symbols.
This talk describes the design and development of an Optical Character Recognition system for printed many-font Indian scripts. The system takes an image of printed text in Devanagari (Hindi, dominant language in North India) or Telugu (a prominent South Indian Language) as an input. It performs a full OCR and provides output that can be directly taken into an editor. Indian scripts are classified into two classes – one class consists of scripts that are written with a prominent headline called Shirorekha and the other class consists of those scripts which do not have a shirorekha. In our work, Devanagari is taken as a representative of the first class and Telugu as a representative of the second class as specified above.
Indian scripts are extremely complicated due to the presence of a vast number of possible combinations of vowels and consonants which are written joined together to form what are called compound characters. The OCR problem becomes even more difficult when text is present in complicated layouts or on complicated backgrounds.
The OCR system designed and implemented is shown to provide excellent results for text images of Telugu and Devanagari. A large number of fonts are considered – 24 for Telugu and 25 for Devanagari and the results are excellent for all these fonts. This is the first reported attempt that works for such a large number of fonts for Indian scripts. Further the recognition rates are enhanced by judiciously implementing schemes for reducing the number of exemplars and the number of features to be stored in the databases. New types of features in transform domain are shown to give better results. The fact that the system works excellently for all these fonts on both Shirorekha-based script as well as non-Shirorekha based Indian script augurs well for the other Indian scripts.
The talk would highlight the main characteristics of Indian scripts and the challenges in development of OCR for them. It would then describe how these challenges are resolved in our work. Considerable emphasis would be laid on practical demonstration of the OCR system apart from explaining its internal structure and logic.

Prof. Anand Srivastav

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Doppelkolloquium, Prof. C Patvardhan, Dayalbagh Educational Institut Agra, India / am 05.10.2016, 14:15 Uhr - 15:00 Uhr

05.10.2016 von 14:15 bis 15:00

Institut für Informatik, Vorbau Ludewig-Meyn-Straße 2, 24118 Kiel, Raum Ü2/K

Titel: Engineering Quantum-inspired Evolutionary Algorithms for solution of large Combinatorial Optimization problems

Abstract: Quantum-inspired Evolutionary Algorithms (QIEA) is a recent branch of EAs. QIEA is a population-based probabilistic Evolutionary Algorithm that integrates concepts from quantum computing for higher representation power and robust search. It maintains a population of individuals in quantum bits or qubits. A qubit coded individual can probabilistically represent a linear superposition of states in the search space and has a better characteristic of population diversity than other representations.
Thus, QEAs are characterized by population dynamics, individual representation, evaluation function etc., as in EAs, as well as quantum bit (qubit) representation, superposition of states etc. as in Quantum Computing. The advantage of the QEAs is that, unlike the other EAs, they can work with small population sizes without being stuck in local minima and without converging prematurely because of loss of diversity. In the extreme case, the immense representation power of the qubits enables use of population size of 1. This reduces the computational burden. Integration of several algorithmic ideas judiciously enables the solution of very large sized problems.
The talk would introduce the QEAs and present some of our recent work on QIEAs and applications. Pointers towards efficient implementations would be discussed. We would also present some directions of future research.

Prof. Anand Srivastav

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Doppelkolloquium, Prof. C Patvardhan, Dayalbagh Educational Institut Agra, India / am 05.10.2016, 14:15 Uhr - 15:00 Uhr

05.10.2016 von 14:15 bis 15:00

Institut für Informatik, Vorbau Ludewig-Meyn-Straße 2, 24118 Kiel, Raum Ü2/K

Titel: Engineering Quantum-inspired Evolutionary Algorithms for solution of large Combinatorial Optimization problems

Abstract: Quantum-inspired Evolutionary Algorithms (QIEA) is a recent branch of EAs. QIEA is a population-based probabilistic Evolutionary Algorithm that integrates concepts from quantum computing for higher representation power and robust search. It maintains a population of individuals in quantum bits or qubits. A qubit coded individual can probabilistically represent a linear superposition of states in the search space and has a better characteristic of population diversity than other representations.
Thus, QEAs are characterized by population dynamics, individual representation, evaluation function etc., as in EAs, as well as quantum bit (qubit) representation, superposition of states etc. as in Quantum Computing. The advantage of the QEAs is that, unlike the other EAs, they can work with small population sizes without being stuck in local minima and without converging prematurely because of loss of diversity. In the extreme case, the immense representation power of the qubits enables use of population size of 1. This reduces the computational burden. Integration of several algorithmic ideas judiciously enables the solution of very large sized problems.
The talk would introduce the QEAs and present some of our recent work on QIEAs and applications. Pointers towards efficient implementations would be discussed. We would also present some directions of future research.

Prof. Anand Srivastav

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Sonderkolloquium, Dr. Alex Q. Huang, North Carolina State University / 09.09.2016

09.09.2016 von 09:30 bis 11:00

Institut für Elektrotechnik, Kaiserstraße 2, 24143 Kiel, Geb. D, "Aquarium"

Titel: 15 kV SiC MOSFET Based Medium Voltage DC/DC Converter

 

Abstract: Medium voltage DC-DC converter is an important element of a medium voltage solid state transformer (SST). It is also considered the most critical element in the future medium voltage DC grid. In reaching medium voltage operation range, device series connection and converter series connection are all viable solutions. This talk will discuss the unique capability of SiC MOSFET in achieving extremely simple and high power density design by operating at very high switching frequency. This is achieved by taking advantage of the zero switching loss in ZVS-based converters and design optimization. Control strategies to improve the reliability of the DC/DC converter is also discussed. In conclusion, 15 kV SiC MOSFET is almost an ideal semiconductor switch that can enable medium voltage conversion at 100 kHz and at a voltage up to 12 kV.

 

Dr. Alex Q. Huang

Dr. Alex Huang received his B.Sc. degree from Zhejiang University, China in 1983 and his M.Sc. degree from Chegdu Institute of Radio Engineering, China in 1986, both in electrical engineering. He received his Ph.D. from Cambridge University, UK in 1992. From 1994 to 2004, he was a founding member and a professor of Center for Power Electronics System (an NSF ERC) at Virginia Tech. Since 2004, he has been a professor of electrical engineering at North Carolina State University and he is currently the Progress Energy Distinguished Professor of Electrical and Computer Engineering. He established the NSF FREEDM Systems ERC in 2008. As part of the FREEDM System concept, he developed the original concept of Energy Internet with the Solid State Transformer serving as an Energy Router. Today, FREEDM Systems ERC is one of the most successful ERCs in the USA with support from many companies. Dr. Huang is also the lead PI and visionary leader behind NCSU’s recent success in establishing the next generation Wide bandgap power electronics manufacturing innovation institute.

Dr. Huang’s research areas are power semiconductor devices, power management integrated circuits, power electronics and its emerging applications such as those in future electric power delivery and management systems. A very active and productive research leader, Dr. Huang has mentored and graduated more than 70 Ph.D. and master students and has generated more than $200m external R&D fundings in the last 20 years.  Dr. Huang has published more than 450 papers in journals and conference proceedings, and holds 20 US patents.  Dr. Huang is the inventor and developer of the ETO thyristor technology. Dr. Huang is a fellow of IEEE and the recipient of the prestigious 2003 R&D 100 award and 2011 MIT Technology Magazine awards. 

 

Prof. Dr. Marco Liserre

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Sonderkolloquium, Dr. Alex Q. Huang, North Carolina State University / 09.09.2016

09.09.2016 von 09:30 bis 11:00

Institut für Elektrotechnik, Kaiserstraße 2, 24143 Kiel, Geb. D, "Aquarium"

Titel: 15 kV SiC MOSFET Based Medium Voltage DC/DC Converter

 

Abstract: Medium voltage DC-DC converter is an important element of a medium voltage solid state transformer (SST). It is also considered the most critical element in the future medium voltage DC grid. In reaching medium voltage operation range, device series connection and converter series connection are all viable solutions. This talk will discuss the unique capability of SiC MOSFET in achieving extremely simple and high power density design by operating at very high switching frequency. This is achieved by taking advantage of the zero switching loss in ZVS-based converters and design optimization. Control strategies to improve the reliability of the DC/DC converter is also discussed. In conclusion, 15 kV SiC MOSFET is almost an ideal semiconductor switch that can enable medium voltage conversion at 100 kHz and at a voltage up to 12 kV.

 

Dr. Alex Q. Huang

Dr. Alex Huang received his B.Sc. degree from Zhejiang University, China in 1983 and his M.Sc. degree from Chegdu Institute of Radio Engineering, China in 1986, both in electrical engineering. He received his Ph.D. from Cambridge University, UK in 1992. From 1994 to 2004, he was a founding member and a professor of Center for Power Electronics System (an NSF ERC) at Virginia Tech. Since 2004, he has been a professor of electrical engineering at North Carolina State University and he is currently the Progress Energy Distinguished Professor of Electrical and Computer Engineering. He established the NSF FREEDM Systems ERC in 2008. As part of the FREEDM System concept, he developed the original concept of Energy Internet with the Solid State Transformer serving as an Energy Router. Today, FREEDM Systems ERC is one of the most successful ERCs in the USA with support from many companies. Dr. Huang is also the lead PI and visionary leader behind NCSU’s recent success in establishing the next generation Wide bandgap power electronics manufacturing innovation institute.

Dr. Huang’s research areas are power semiconductor devices, power management integrated circuits, power electronics and its emerging applications such as those in future electric power delivery and management systems. A very active and productive research leader, Dr. Huang has mentored and graduated more than 70 Ph.D. and master students and has generated more than $200m external R&D fundings in the last 20 years.  Dr. Huang has published more than 450 papers in journals and conference proceedings, and holds 20 US patents.  Dr. Huang is the inventor and developer of the ETO thyristor technology. Dr. Huang is a fellow of IEEE and the recipient of the prestigious 2003 R&D 100 award and 2011 MIT Technology Magazine awards. 

 

Prof. Dr. Marco Liserre

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Kolloquiumsvortrag, Dr. Sebastian Wintz, Paul Scherrer Institute Villingen, Switzerland / 11.07.2016

11.07.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: "Topological Spin Textures as Spin Wave Emitters"

Abstract:

Today, spin waves are seen as high potential information carrier for next-generation information and communication devices [1]. This view is based on the substantially reduced energy dissipation and much smaller wavelengths of spin waves compared to traditional charge current signals. For the implementation of spin wave technology into applicable devices, however, novel concepts for the generation, manipulation, and detection of spin waves are yet to be found. With respect to spin wave generation, it was typically necessary to either use patterned transducers with sizes on the order of the desired wavelengths (striplines or point-contacts), or to generate those spin waves parametrically by a double-frequency spatially uniform microwave signal [2]. In this presentation, I will report on a newly discovered concept for the generation of spin waves, which overcomes the bandwidth limitations in terms of the minimum wavelength limit given by the patterning size. This method utilizes the translation of natural topological defects, namely the gyration of magnetic vortex cores to generate isotropically propagating,  non-reciprocal  spin  waves  [3].  Experimentally,  such  spin-waves  were directly  observed  by  means  of  time-resolved x-ray  microscopy. Furthermore, I  will address directional and one-dimensional spin wave emission in anistropic magnetic systems.

[1] D. Rosso, “International Technology Roadmap for Semiconductors Explores Next 15

Years of Chip Technology”, www.semiconductors.org, (2014).

[2] A. G. Gurevich and G. A. Melkov, Magnetization Oscillations and Waves. New York: CRC, 1996.

[3] S. Wintz et al., submitted (2015).

Today, spin waves are seen as high potential information carrier for next-generation information and  communication devices.  This  is  based  on  the  substantially reduced energy dissipation and much smaller wavelengths of spin waves compared to traditional charge current signals. For a device implementation, however, novel concepts for the generation, manipulation, and detection of spin waves are yet to be found. Here, we report on a newly discovered concept for the generation of spin waves, which overcomes typical bandwidth limitations of traditional spin wave excitation methods. Our approach utilizes the  gyration  of  magnetic  vortex  cores  to  generate  isotropically  propagating,  non- reciprocal spin waves.

 

Prof. McCord

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Kolloquiumsvortrag, Prof. Nini Pryds, Departement for Energy Conversion and Storage, Technical University of Denmark / 04.07.2016

04.07.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"


Titel: "Highly Efficient Caloric Devices"

Abstract: The demand for high cooling power devices with a high efficiency is a challenge for the appliance market. An increasing number of novel caloric devices have been presented recently. The results and performance are continually improving, but the efficiency of these devices is still too low to allow the technology to break though commercially. At DTU Energy we have developed and tested several high performance Calorics devices. I will present our past and present activities related to designing magnetic refrigeration devices and in particular I will describe and show the recent results obtained with MAGGIE. Furthermore, in this talk we will present a new elastocaloric cooling system based on the active regeneration principle. Such a system is analogue to the active magnetic regenerator. The system development, its operational principle and the preliminary results (the temperature span and cooling power at different operating conditions) will be also presented and discussed.

 

 

Prof. Quandt

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Sonderkolloquium, Prof. Dr. Olaf Landsiedel, Chalmers University of Technology, Göteborg / 28.06.2016, 14:30 - 15:30 Uhr

28.06.2016 von 14:30 bis 15:30

Christian-Albrechts-Platz 4, Raum 1304 a

Titel: Chaos: Versatile and Efficient All-to-All Data Sharing and In-Network Processing at Scale

Abstract: An important building block for low-power wireless systems is to efficiently share and process data among all devices in a network. We introduce Chaos, a primitive that natively supports all-to-all data sharing in low-power wireless networks. Different from current approaches, Chaos embeds programmable in-network processing into a communication support based on synchronous transmissions. We show that this design enables a variety of common all-to-all interactions, including network-wide agreement and data aggregation. Chaos scales efficiently to networks consisting of hundreds of nodes, achieving severalfold improvements over the state of the art in radio duty cycle and latency at high reliability. For example, Chaos computes simple aggregates, such as the maximum, in a 100-node multi-hop network within less than 90 milliseconds using off-the-shelf IEEE 802.15.4 radios.
Moreover, Chaos departs from the traditional message-based programming paradigm of networking and utilizes an approach that is similar to shared memory: Nodes maintain local state which they merge with any received state and which they in-turn share with neighboring nodes. We discuss how this paradigm changes protocol design and implementation. For example, we show how Chaos can provide widespread communication patterns such as collection, dissemination, agreement, and aggregation at high performance and low implementation complexity.

 

Prof. Dr. Thomas Wilke

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Kolloquiumsvortrag, Prof. Dr. Nikolai Axmacher, Institute of Cognitive Neuroscience, Department of Neuropsychologie, Ruhr University Bochum / 27.06.2016

27.06.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel:  Network mechanisms of memory representations in the human brain

Abstract:  How can the neural representations of specific experiences, or engrams, be identified in the human brain? Which neural properties determine the accuracy of memory traces, how are they altered in diseases that involve memory dysfunction, and can electric stimulation be used to restore them? In this talk, I will describe the neural mechanisms supporting content-specific representations in perception and memory, and how these findings shed light on early disease processes and may help developing new therapeutic approaches.

In the first part of the talk, I will present our basic framework for studying network representations in the human brain. In particular, analyzing brain oscillations and oscillatory interactions allows us to characterize regional activation patterns and mechanisms supporting inter-regional communication and plasticity. In the second part, I will describe some recent studies on network representations of memory traces. Using intracranial EEG recordings in epilepsy patients as well as simultaneous EEG/fMRI recordings in healthy participants, we found that stimulus-specific representations are reinstantiated during memory recall and spontaneously reactivated during awake resting state and sleep. As I will show in the third part, analyzing content-specific representations may be clinically relevant to identify early pathophysiology and potential new therapies in Alzheimer’s dementia. Using fMRI in genetic risk carriers for Alzheimer’s disease, we observed impaired entorhinal grid cell-like representations and altered navigational strategies. Furthermore, we found that deep brain stimulation to the medial temporal lobe may be a novel therapeutic option for ameliorating memory dysfunction; understanding the oscillatory basis of memory processes may help optimizing stimulation parameters.

Prof. Kohlstedt

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Kolloquiumsvortrag, Prof. Sudhir R. Ghorpade Department of Mathematics Indian Institute of Technology Bombay / am Donnerstag, 23.06.2016, 16:00 - 17:00 Uhr

23.06.2016 von 16:00 bis 17:00

Christian-Albrechts-Platz 4, Raum 910

Title:  Systems of polynomial equations over finite fields and linear codes

 

Abstract: 

 We consider the problem of determining the maximum number of common solutions of a bunch of polynomials over a finite field. The simplest case is of course of a single (nonzero) polynomial in one variable, where the degree usually gives the maximum number of solutions. In the general case of several polynomials in several variables, the problem is meaningful and interesting when the base field is finite and the solutions are sought in the corresponding affine or projective space over the given finite field. When these polynomials are assumed linearly independent and of a degree bounded by a fixed positive integer, the problem is equivalent to a problem in coding theory, namely, that of determining the generalized Hamming weights of Reed-Muller codes. The known solution in this case, due to Heijnen and Pellikaan (1998) uses results in combinatorics such as Kruskal-Katona theorem.

The case of systems of linearly independent multivariate homogeneous polynomials, all of the same degree, where the zeros are considered in a projective space over the given finite field is perhaps even more interesting. There is an elaborate conjecture of Tsfasman and Boguslavsky that predicts the maximum value when the degree of the homogeneous polynomials is not too large in comparison to the size of the finite field. Special cases of the conjecture are known to be true, thanks to the results of Serre (1991) and Boguslavsky (1997), but the general case has been open for quite some time.


We will give a motivated account of the above problem and its alternative formulations while briefly explaining the relevant background. We will then describe some recent developments that has led to significant new results concerning the general case. This is based mainly on a joint work with Mrinmoy Datta.
 

Prof. Andan Srivastav

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Kolloquiumsvortrag, Prof. Richard James, University Minnesota USA / 20.06.2016

20.06.2016 von 17:15 bis 18:45

Institut für Materialwissenschaften, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: Compatibility, hysteresis and the direct conversion of heat to electricity

Abstract: Big first order phase transformations in solids can be highly reversible, if the lattice parameters are “tuned” to satisfy certain relations that promote the compatibility between phases.  We outline the basic theory behind this tuning and give examples of recently discovered alloys.  Some of these alloys have thermal hysteresis as low as 0.2 C despite having an 8% transformation strain.   The lowered hysteresis correlates with the reversibility of the transformation under repeated cycling, and links to important discoveries madein Kiel.  We use this kind of tuning, together  with the lattice parameter sensitivity of magnetic properties and the presence of a jump of lattice parameters at the phase transformation, to find some interesting new multiferroic Heusler alloys: briefly, multiferroism by reversible phase transformation.  These alloys can be used in diverse ways for the direct conversion of heat to electricity, and provide interesting possible ways to recover the vast amounts of energy stored on earth at small temperature difference.

Prof. Quandt

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Sonderkolloquium am 09.06.2016, Prof. Xiaoyi Jiang, Universität Münster / Vortrag im Rahmen der Schleswig-Holsteinischen Bildverarbeitungstage

09.06.2016 von 14:05 bis 14:50

Driftmann-Hörsaal, Olshausenstr. 75, Hörsaal 3

Titel: "Biomedical Imaging: Challenges and Chances for Computer Vision"

Abstract: With the widespread use of imaging technologies in basic research and routine clinical practice, medical researchers and physicians are faced with analyzing an ever-increasing amount of complex image data. Also in biology imaging has become an indispensable tool, for instance for behavior studies of small animals. Many computer vision algorithms have been successfully adapted and applied to biomedical imaging applications. However, the specific characteristics of biomedical image data pose new challenges and force researchers to develop novel concepts and algorithms. In fact, biomedical imaging can be seen as another driving force for computer vision research. This talk emphasizes this fundamental research view of biomedical computer vision. A variety of topics will be motivated by current research in biology and medicine. The related challenges, concepts, and algorithms will be discussed.


Prof. Koch

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Sonderkolloquium am 09.06.2016, Prof. Yoav Y. Schechner, Technion, Haifa, Israel / Vortrag im Rahmen der Schleswig-Holsteinischen Bildverarbeitungstage

09.06.2016 von 13:20 bis 14:00

Driftmann-Hörsaal, Olshausenstr. 75, Hörsaal 3

Titel: "The next best underwater view"

Abstract:  To image in high resolution large and occlusion-prone scenes, a camera must move above and around. Degradation of visibility due to geometric occlusions and distances is exacerbated by scattering underwater. Moreover, underwater and in other media, artificial lighting is needed. We propose to jointly optimize the path of platforms carrying either a camera or a light source. The work generalizes the next best view concept of robot vision to scattering media and cooperative movable lighting.

Prof. Koch

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Kolloquiumsvortrag, Prof. Partha Roop, Department of Electrical and Computer Engineering, University of Auckland / 03.06.2016

03.06.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: The science of bio-remulation for Executable Organ on Chips

Abstact: 

The use of simulation models in biology is extensively studied. Emulation is used, in contrast to simulation, when a controller (such as a pacemaker) for a biological process (the heart) needs validation in real-time. Here, the pacemaker is connected in closed-loop with a living heart. This may occur either during the clinical trial phase with human subjects or animal models. We argue that such emulation is expensive, time limiting, and has associated ethical considerations. We propose the science of remulation (reverse-emulation) as an alternative paradigm. Here, we develop executable models of the biological process (say the cardiac conduction system) that is realisable on a reprogrammable computer chip.

Such an ``Executable Organ on Chip'' (ExOoC) provides high-fidelity and real-time capabilities like a real heart, from the point of view of the pacemaker. Remulation of such ``Executable Organ on Chip'' (ExOoC) has not only excellent potential for medical device validation and certification but also can be used for personalisation and
non-invasive diagnostics. We have developed the first high-fidelity remulation model of the cardiac conduction system and have used this to validate a pacemaker in real-time.

Prof. Dr. Reinhard von Hanxleden

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Kolloquiumsvortrag, Dr. Jörg Hübner, Technical University of Denmark / 30.05.2016

30.05.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: Micro and Nano structuring of Silicon at DTU Danchip.

Abstract:  Etching of silicon is the basic technology step for a large variety of MEMS, NEMS and microfluidic applications. Even the fabrication of  large area nanostructure in polymere starts in our examples with lithography and etch of silicon. The talk will therefore after a short introduction to DTU Danchip focus on plasma etching of silicon. The plasma chemistry and physics during silicon etch poses challenges and opportunities, which will be using examples reaching from nanopillars for SERS enhancement to X-ray compound lenses. There will also be a short excursion into Atomic Layer Deposition and some results on structures realised with this very versatile technology.

 


 


Prof. Adelung

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Doppelkolloquiumsvortrag, Prof. Dr. Ulrich Meyer, Algorithm Engineering Group, Institute of Computer Science, Goethe University, Frankfurt / 27.05.2016, 16:15 - 17:30 Uhr

27.05.2016 von 16:15 bis 17:30

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Generating and Traversing Large Graphs in External-Memory

Abstract:

Large graphs arise naturally in many real world applica-
tions. The actual performance of simple RAM model algo-
rithms for traversing these graphs (stored in external mem-
ory) deviates significantly from their linear or near-linear
predicted performance because of the large number of I/Os
they incur. In order to alleviate the I/O bottleneck, many
external memory graph traversal algorithms have been de-
signed with provable worst-case guarantees. In the talk I
highlight some techniques used in the design and engineer-
ing of such algorithms and survey the state-of-the-art in
I/O-efficient graph traversal algorithms. I will also report
on recent work concerning the generation of massive scale
free networks under resource constraints.

 

Prof. Srivastav

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Doppelkolloquiumsvortrag, Prof. Dr. Stefan Sauter, Universität Zürich / 27.05.2016, 14:15 - 16:00 Uhr

27.05.2016 von 14:15 bis 16:00

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Title: A Posteriori Error Majorant for Elliptic Partial Differential Equations with Applications to Homogenization.

Abstract:  In our talk, we will present new two-sided estimates of modeling errors for linear elliptic boundary value problems with periodic coefficients solved by homogenization method. Our approach is based on the concept of functional a posteriori error estimation. The estimates are obtained for the energy norm and use solely the global flux of the non-oscillatory solution of the homogenized model and solutions of some cell problem. Numerical tests illustrate the efficiency of the estimates.

Prof. Börm

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Sonderkolloquium Dr. Alzola /13.05.2016

13.05.2016 von 11:00 bis 12:00

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: "Design and resonance-damping of LCL-filter based grid-tie converters and recent developments on power electronics control"

Abstract - The first part of the lecture will deal with LCL-filter based three-phase grid-tie converters. Adopting an LCL-filter, instead of an L-filter, allows using a reduced value for the total inductance and so reducing losses and preserving dynamics. However, stability problems can arise if the present resonance is not properly damped. Passive damping uses additional resistors and active damping modifies the control algorithm. Many solutions have been proposed in a vast amount of publications. For this lecture, different configurations for passive damping will be explained along with the following active damping procedures: lead-lag network, capacitor-current feedback and notch filter. Stability and robust design against grid line inductance variations will also be considered. The last part of the lecture explores the opportunity of harmonic mitigation at distribution level in small hybrid ac/dc building by using a centralized power factor corrector (PFC) with large bandwidth. It is foreseeable an increased presence of hybrid ac/dc buildings with coexisting ac and dc infrastructures because of the unprecedented expansion of native dc powered equipment (LEDs and consumer electronics). The proposals provide all the steps for the straightforward control design of the PFC and its harmonic mitigation function (HMF) with fast calculations. The HMF requires only software modifications in the PFC and one sensor to measure the nonlinear load.

 

Prof. Liserre

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Kolloquiumsvortrag, Dr. Otwin Breitenstein, Max-Planck-Institut für Mikrostrukturphysik in Halle / 02.05.2016

02.05.2016 von 17:15 bis 18:45

Institut Ostufer, Kaiserstraße 2, 24143 Kiel, Raum: Geb. D, "Aquarium"

Titel: "Lock-in Thermography -- A Universal Tool for Evaluating Electronic Devices and Materials"

Abstract:

Lock-in Thermography (LIT) is a special variant of the well-known infrared thermography method, which uses a thermocamera detecting light in the thermal radiation range (typically 3 - 5 µm). The camera is connected to a computer, which switches certain power dissipation (heat) sources in the imaged object periodically on and off at a certain frequency. The incoming images are evaluated according to the lock-in principle, which is equivalent to connecting each image pixel to a lock-in amplifier. The primary result of a LIT measurement are the temperature modulation amplitude image and the phase image, which is a measure of the time delay of the surface temperature modulation with respect to the power modulation. Advantages of LIT compared to conventional (steady-state) thermography are a drastically improved sensitivity due to its averaging nature and a suppression of the lateral heat diffusion due to its dynamic nature.

In this talk the realization of LIT will be explained and a number of applications will be reported. Since the modulated heat sources in the investigated object can be of very different nature, LIT may be applied to study a lot of different physical problems. This talk reports on the application of LIT to non-destructive evaluation (looking below the surface of bodies), local efficiency analysis of solar cells, measurement of Peltier coefficients, failure analysis of integrated circuits, imaging of water adsorption in biological specimens, and investigation of spin-caloritronic effects in magnetic materials.

Prof. Adelung

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Kolloquiumsvortrag, Prof. Dr. Joachim Biskup, TU Dortmund, Fakultät für Informatik / 22.04.2016

22.04.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Straße 2, 24118 Kiel, Raum: Übungsraum 2/K

Titel: Publishing Inference-Proof Relational Data: Design, Implementation, Optimization and Experiments

Abstract:

An agent might want to share information maintained by a relational database by means of data publishing, i.e., by generating a view customized for the further unrestricted usage by the anticipated clients. Often, however, the usability of the view has to be confined to ensure the confidentiality of particular pieces of information in need of being excluded from sharing. Within the framework of Controlled Interaction Execution, we have designed a sound and complete generation procedure for an inference-proof (i.e., consistent and confidentiality-preserving) view that has minimal distortion distance to the original database instance. Confidentiality is achieved regarding a policy declared in terms of first-order logic sentences to be kept hidden. Consistency ensures the compliance with postulated a priori knowledge of the clients, expressed as first-order logic sentences, too. Conceptually, the generation procedure performs a depth-first search for satisfying the constraints and follows a branch-and-bound strategy for minimizing distortions. We have further provided an actual implementation of the generation procedure together with several optimizations. In particular, we exploited sophisticated local lower bounds on the number of additional distortions in subtrees to be explored to prune them early, and we employed coordinated parallelization for searching in many subtrees concurrently. Moreover, we have performed an experimental evaluation in terms of runtime behavior. Finally, we have also explored to replace depth-first searching by priority searching, exhibited special cases that can be handled more efficiently, considered heuristics for only approximating distortion minimality, and explored options of refined mechanisms to employ and invent constants to resolve current violations of constraints.
The original design was joint work with Lena Wiese (J. Biskup/L. Wiese, Journal of Computer Security 16 (2008) 477–494; L. Wiese, Dissertation, TU Dortmund 2009; J. Biskup, L. Wiese, Theoretical Computer Science 412 (2011) 4044–4072).
The implementation, the optimizations and the evaluation are joint work with Christine Dahn, Katharina Diekmann, Ralf Menzel, Dirk Schalge und Lena Wiese (manuscript submitted for publication).

Prof. Thalheim

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Kolloquium Prof. Dr. Andreas Taubert, Universität Potsdam / 11.04.2016

11.04.2016 von 17:15 bis 18:45

Institut für Materialwissenschaft, Raum: Geb. D, Aquarium, Kaiserstraße 2, 24143 Kiel

Titel: Biomimetic calcium phosphate mineralization - effects of surfaces and interfaces

Abstract:

Calcium phosphate is one of the most important biominerals. It comes in a variety of phases, e.g. hydroxyapatite, brushite, etc., and is a key component in bones, teeth, and tendons.1,2 Biomimetic calcium phosphate mineralization, that is, the synthesis of calcium phosphate/organic composites using a synthetic template or additive, provides access to a large variety of calcium phosphate composites that could for instance be useful for bone repair. However, the details of calcium phosphate nucleation, growth, and phase selection are not fully understood yet. To rationally design tailored materials for specific applications such as healthcare, this would however be essential.Among others, interfaces are a key factor affecting the formation, structure, composition, and properties of both the calcium phosphate deposits and the resulting hybrid materials. In spite of this, there are only relatively few studies on the role of surfaces and interfaces on calcium phosphate growth.The presentation will present data on calcium phosphate formation on model surfaces, both at the solid-liquid3 and the liquid-air interface,4-7 and discuss the effects of these interfaces on crystal formation. A special focus is put on the effects of polycations, such as poly(2-dimethylethylamino methacrylate) (PDMAEMA), because polycations have been less extensively studied than polyanions and there is hence a lack of information on their role in calcium phosphate mineralization. This also applies to the effects of oligomeric compounds as mineralization templates.8 Our studies show that not only the type of surface (anionic vs. cationic) but also the charge of each polymer surface (charged vs. uncharged) strongly affects the outcome of the mineralization process. A preliminary hypothesis of how polycations may regulate calcium phosphate is also proposed9 and – time permitting – I will also present some recent data on how ionic liquids can be used to generate interesting composite materials.10

 

References

(1)       Calcium Phosphates in Biological and Industrial Systems; Kluwer Academic Publishers: Norwell-Dordrecht, 1998.

(2)       Handbook of Biomineralization; Wiley-VCH: Weinheim, 2007.

(3)       Löbbicke, R.; Chanana, M.; Schlaad, H.; Pilz-Allen, C.; Günter, C.; Möhwald, H.; Taubert, A. Biomacromolecules 2011, 12, 3753.

(4)       Casse, O.; Colombani, O.; Kita-Tokarczyk, K.; Müller, A. H. E.; Meier, W.; Taubert, A. Faraday Discuss. 2008, 139, 179.

(5)       Junginger, M.; Bleek, K.; Kita-Tokarczyk, K.; Reiche, J.; Shkilnyy, A.; Schacher, F.; Müller, A. H. E.; Taubert Nanoscale 2010, 2, 2440.

(6)       Junginger, M.; Kita-Tokarczyk, K.; Schuster, T.; Reiche, J.; Schacher, F. A.; Müller, A. H. E.; Cölfen, H.; Taubert, A. Macromol. Biosci. 2010, 10, 1084.

 (7)       Junginger, M.; Kübel, C.; Schacher, F. H.; Müller, A. H. E.; Taubert, A. RSC Adv. 2013, 3, 11301.

 (8)       Hentrich, D.; Junginger, M.; Bruns, M.; Börner, H. G.; Brandt, J.; Brezesinski, G.; Taubert, A. Cryst. Eng. Comm. 2015, DOI: 10.1039/C4CE02274B

 (9)       Shkilnyy, A.; Schöne, S.; Rumplasch, C.; Uhlmann, A.; Hedderich, A.; Taubert, A. Colloid Polym. Sci. 2011, 289, 881.

(10)     Salama, A.; Neumann, M.; Günter, C.; Taubert, A. Beilstein. J. Nanotechnol. 2014, 5, 1553.

 

Prof. Selhuber-Unkel

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Sonderkolloquiumsvortrag: Prof. Francesco Iannuzzo, Aalborg University/ 19.02.16

19.02.2016 von 12:15 bis 13:15

Institut für Elektrotechnik und Informaationstechnik, Kaiserstr. 2, 24143 Kiel, Geb. D Raum: "Aquarium"

Titel: Activities on robustness of power devices at CORPE- Aalborg University

 

Abstract:
Reliability challenges in power electronics for modern wind power generation system are pointed out, together with state-of-the-art testing and modelling techniques adopted for robustness assessment of IGBT and SiC power modules under abnormal conditions. Some details and case studies will be illustrated about running activities in CORPE – center of power electronics at Aalborg university, Denmark.

Prof. Liserre

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Kolloquiumsvortrag, Prof. Tamas Kerekes, Aalborg University Denmark / am 13.02.2017

13.02.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Design of residential Photovoltaic systems – a guideline

Abstract: Photovoltaic technology continues to increase its share in the global energy market, with an exceptionally fast growth in the last few decades reaching a cumulative capacity of 227 GW by the end of 2015, with a predicted extra 50GW of new installations for 2016. According to a report from SolarPower Europe (former European Photovoltaic Industry Association (EPIA)), the price of PV systems has decreased more than 75% in the last 10 years, making PV cost competitive with fossil-based generation in several countries. Fueled by this strong cost reduction, the PV industry is transitioning from being driven by subsidies into a viable option for investment for both large power plants and residential installations on a pure cost competition basis. Residential PV systems are a key element in the success story of PV rooftop installations and large utility scale plants share about 50% of new installations today. ENTSO_E forecasts that by 2025 European power generation will have over 50% renewable, where solar will be expected to have a major role. If we combine the solar increase with even more wind penetration, then this will require a much more flexible system in order to make the best use of renewable energy sources when they are available. Among the different flexibility options, storage is one solution that allows to respond quickly to balancing needs by absorbing the excess solar generation at peak times and releasing it during periods of lower production, but high load demand. By making the best use of cheap renewable electricity when it is available, storage can make the energy system more cost-effective. By adapting to demand and limiting the possibility of peak pricing, storage will also have a balancing effect on prices throughout the day. If solar is combined with storage then this will act as a bridging technology between the electricity, heating and cooling as well as transport sectors. Besides the rapidly developing battery storage capacity, the electrification of the transport sector and the use of electricity for heat purposes allow for an integrated approach of the energy system. This will provide new opportunities for European consumers and businesses, whilst potentially offering a variety of services to grid operators.

Prof. Marco Liserre

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Kolloquiumsvortrag: Prof. Dr. Jens Markus Melenk, TU Wien / 12.02.16

12.02.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, 24118 Kiel, Übungsraum 2

Titel: Stability and convergence of Galerkin discretizations of the Helmholtz equation

Abstract:

We consider boundary value problems for the Helmholtz equation at large wave numbers $k$. In order to understand how the wave number $k$ affects the convergence properties of discretizations of such problems, we develop a regularity theory for the Helmholtz equation that is explicit in $k$. At the heart of our analysis is the decomposition of solutions into two components: the first component is an analytic, but highly oscillatory function and the second one has finite regularity but features wavenumber-independent bounds. This new understanding of the solution structure opens the door to the analysis of discretizations of the Helmholtz equation that are explicit in their dependence on the wavenumber $k$. As a first example, we show for a conforming high order finite element method that quasi-optimality is guaranteed if (a) the approximation order $p$ is selected as $p = O(\log k)$ and (b) the mesh size $h$ is such that $kh/p$ is small. The work is joint with Stefan Sauter (Zurich).

Prof. Steffen Börm

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Kolloquiumsvortrag: Prof. Dr.-Ing. Dr. med. Steffen Leonhardt - RWTH Aachen / 08.02.16

08.02.2016 von 17:15 bis 18:45

Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, 24143 Kiel, Geb. D Raum: "Aquarium"

Titel:  Methods for contact-free Monitoring of Vital Signs

 

Abstract:

After a short introduction to the rationale for noncontact monitoring of vital signs, several measurement modalities will be presented, including

- ballistocardiography (BCG)

- contact-free ECG monitoring

          - contact-free monitoring of pulse and breathing by magnetic induction (MIM), 

           - contact-free monitoring of temperature and breathing by Infrared Thermography (IRT), and

        -  contact-free monitoring of perfusion, ventilation and oxygen saturation by reflective Pulse Plethysmography Imaging (PPGI).

A comparison of these methods with respect to penetration depths, modes of energy injection, price, etc. will conclude the talk.

Prof. Schmidt

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--- entfällt!!! --- Kolloquiumsvortrag, Prof. Knut Graichen, Institut für Mess-, Regel- und Mikrotechnik, Universität Ulm / am 06.02.2017

06.02.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Eingebettete nichtlineare Optimierung und MPC im (Sub-)Millisekundenbereich

Abstract: Nichtlineare Optimierungsverfahren und deren Anwendung im Zusammenhang mit der nichtlinearen modellprädiktiven Regelung (NMPC) sind in der Regelungstechnik insbesondere für dynamische Systeme mit mehreren Stellgrößen und zur Berücksichtigung von Systembeschränkungen von zunehmender Bedeutung. Eine Herausforderung bei der Umsetzung dieser Verfahren in der Praxis ist jedoch der hohe numerische Aufwand und die algorithmische Komplexität, insbesondere bei hochdynamischen Systemen mit Abtastzeiten im (Sub-)Millisekundenbereich. Die Problematik der Umsetzbarkeit wird durch die Tatsache weiter verschärft, dass Hardware-Lösungen in der industriellen Praxis häufig sehr limitierte Ressourcen besitzen. Als Beispiele seien Speicherprogrammierbare Steuerungen (SPS) oder Steuergeräte (Electronic Control Unit – ECU) genannt. Diesen Herausforderungen kann im Sinne eines eingebetteten Entwurfs durch die Verwendung von zugeschnittenen Optimierungsalgorithmen in Kombination mit einer echtzeitfähigen Auswertung begegnet werden.

Im Hinblick auf die oben genannten Herausforderungen präsentiert der Vortrag einen Ansatz zur nichtlinearen dynamischen Optimierung und modellprädiktiven Regelung, der eine echtzeitfähige Umsetzung selbst auf leistungsschwacher Hardware ermöglicht. Neben der methodischen und algorithmischen Vorstellung wird das Verfahren anhand von ausgewählten mechatronischen Beispielen erläutert.

Prof. Dr.-Ing. Thomas Meurer

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Sonderkolloquiumsvortrag: Prof. Alex Huang, NC State University Raleigh, 03.02.16

03.02.2016 von 11:00 bis 12:00

Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, Geb. D Raum: "Aquarium"

Titel: Energy Internet and Critical Power Electronics Technology

 

Abstract:

Dr. Huang proposed the revolutionary FREEDM (Future Renewable Electric Energy Delivery and Management) System in 2007 as a novel architecture suitable for plug-and-play of distributed renewable energy and distributed energy storage devices. Motivated by the success of the Information Internet, the architecture was put forward as a transformative platform for an Energy Internet.  In the Information Internet, people share information in a plug and play manner. In the envisioned ‘Energy Internet’, a vision for sharing of the energy is proposed for ordinary citizen and home owners. Key enabling technologies required to achieve such a vision will be discussed. Among many of the key technologies, the development of advanced wide bandgap power semiconductor devices and medium voltage power electronics systems will be discussed and highlighted.


Liserre

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Kolloquiumsvortrag: Prof. Ralf Metzler, Universität Potsdam / 01.02.16

01.02.2016 von 17:15 bis 18:45

Institut für Materialwissenschaft, Kaiserstr. 2, Geb. D Raum: "Aquarium"

Titel: Ergodicity violation and ageing: From granular gases to living cells

Abstract:

In 1905 Einstein formulated the laws of diffusion, and in 1908 Perrin published his Nobel-prize winning studies determining Avogadro's number from diffusion measurements. With similar, more refined techniques the diffusion behaviour in complex systems such as the motion of tracer particles in living biological cells is nowadays measured with high precision. Often the diffusion turns out to deviate from Einstein's laws. This talk will discuss the basic mechanisms leading to anomalous diffusion as well as point out the physical consequences. In particular the unconventional behaviour of non-ergodic, ageing systems will be discussed within the framework of different stochastic processes [1,2]. The effects of non-ergodicity and ageing will be analysed in detail for specific physical systems such as the motion of particles in granular gases, tracer diffusion in flexible gels and in living biological cells, as well as in quenched energy landscapes. Moreover, many-particle effects with interactions will be addressed.

[1] R. Metzler, J.-H. Jeon, A. G. Cherstvy & E. Barkai, Phys. Chem. Chem. Phys. 16, 24128 (2014). [2] E. Barkai, Y. Garini & R. Metzler, Phys. Today 65(8), 29 (2012).

Selhuber-Unkel

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Kolloquiumsvortrag, Dr. Philip Hövel, Inst. f. Theoretische Physik, TU Berlin, / am 30.01.2017

30.01.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrontechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Control of cluster synchronization in delay-coupled oscillators by network adaptation

Abstract:

Adaptive networks are characterized by mutual interactions between the dynamics of the nodes on one hand and a co-evolution of the coupling topology on the other hand: The topology evolves according to the state of the system, while at the same time the dynamics on the network is influenced by that changing topology.

In my presentation, I will discuss an adaptive control scheme for the control of in-phase and cluster synchronization in delay-coupled networks of "Stuart-Landau oscillators". This paradigmatic normal form arises naturally in an expansion of systems close to a Hopf bifurcation. Based on an automated control scheme called "speed-gradient method", the topology of a network adjusts itself in a self-organized manner such that the target state is realized. I will provide numerical evidence that the networked system settles into different cluster states depending on the pre-defined control function.

Furthermore, I will demonstrate that the emerging topology of the network is modulated by the coupling delay. If the delay time is a multiple of the system's eigenperiod, the coupling within a cluster and to neighboring clusters is on average positive (excitatory), while the coupling to clusters with a phase lag close to pi is negative (inhibitory). For delay times equal to odd multiples of half of the eigenperiod, the opposite holds: Nodes within one cluster and of neighboring clusters are coupled by inhibitory links, while the coupling to clusters distant in phase state is excitatory. In addition, the control scheme is able to construct networks such that they exhibit not only a given cluster state but also oscillate with a prescribed frequency. Finally, I will illustrate the effectiveness of the speed-gradient method in cases, where only part of the network is accessible.

References:

J. Lehnert, Controlling synchronization patterns in complex networks, Springer Theses, Springer, (2016).


J. Lehnert, P. Hövel, A. A. Selivanov, A. L. Fradkov, and E. Schöll: Controlling cluster synchronization by adapting the topology Phys. Rev. E 90, 042914 (2014).

E. Schöll, A. A. Selivanov, J. Lehnert, T. Dahms, P. Hövel, and A. L. Fradkov: Control of
synchronization in delay-coupled networks, Int. J. Mod. Phys. B 26, 1246007 (2012).

A. A. Selivanov, J. Lehnert, T. Dahms, P. Hövel, A. L. Fradkov, and E. Schöll: Adaptive synchronization for delay-coupled networks of Stuart-Landau oscillators, Phys. Rev. E 85, 016201 (2012).

J. Lehnert, P. Hövel, V. Flunkert, P. Y. Guzenko, A. L. Fradkov, and E. Schöll: Adaptive tuning of feedback gain in time-delayed feedback control, Chaos 21, 043111 (2011).

-- Dr. Philipp Hövel Junior Research Group Leader

Prof. Hermann Kohlstedt

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Kolloquiumsvortrag: Prof. Dr. Ralf Hiptmair, ETH Zürich / 29.01.2016

29.01.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, 24118 Kiel, Übungsraum 2

Titel:  Maxwell and the Hodge Laplacian


Abstract:

The linear Maxwell equations in frequency domain can be recast in several dierent forms,
as rst-order system, as second-order equation involving the double-curl operator, or a
second-order equation featuring the Hodge-Laplacian 􀀀 := curl curl􀀀grad div.
Variational equations or boundary integral equations arising from these dierent formulations
are equivalent, but pose very dierent challenges when it comes to discretization.
For instance, there is the startling failure of smooth functions to be dense in
H0(curl; ) \H(div; ) for certain domains . This foils direct Galerkin discretization
of the Hodge-Laplacian and enforces the use of a mixed approach.
Similarly, rst-kind boundary integral operators associated with u = 0 display a strange
lack of coercivity. The culprit is the failure of certain combinations of boundary conditions
for to ensure uniqueness of solutions of the related boundary value problems.

Prof. Börm

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Kolloquiumsvortrag: Prof. Ludwig Schultz - IFW Dresden/TU Dresden / 25.01.16

25.01.2016 von 17:15 bis 18:45

Institut Materialwissenschaft, Kaiserstr. 2, 24143 Kiel, Geb. D, Raum: "Aquarium

Titel:

Interaction of Ferromagnetic and Superconducting Permanent Magnets:

Superconducting Levitation

 

Abstract:

New means of urban transportation and logistics will become realistic with superconducting magnetic bearings using bulk high-temperature superconductors. The advantage of super­con­ducting magnetic levitation is that it is passively stable without any electronic control, but with attracting and repelling forces to suspend a vehicle pendant or standing upright from zero to high speed. These are perfect conditions for a rail-bound, individual transport with cabins for 4 to 5 passengers, requested call by call. They will levitate without noise over a track made of rare-earth permanent magnets, saving energy and travel time. A big step forward in this vision has been made in Dresden. The world largest research and test facility for transport systems using bulk high-temperature superconducting material in the levitation and guidance system, in combination with a permanent magnet track, was put into operation. A vehicle for 2 passengers, equipped with linear drive propulsion, noncontact energy supply, second braking system, and various test and measurement systems is running on an 80 m long, oval driveway. In the presentation, the principle of superconducting levitation by flux pinning in high-temperature super­con­ductors will be described. Based on this, an over­view of the SupraTrans II research facility and future directions of super­conductivity-based magnetic levitation and bearing for automation technology, transportation, and medical treatment under enhanced gravity will be given. Also the superconducting hoverboard, recently presented by Lexus, will be presented.

Prof. McCord

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Kolloquiumsvortrag am 23.01.2017, Dr. Alexander Schaum, Lehrstuhl für Regelungstechnik, CAU zu Kiel

23.01.2016 von 17:15 bis 18:45

Technische Fakultät, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel:  Dissipativitätsbasierter Regler- und Beobachterentwurf

Abstract: Dissipativitätsbasierter Regler- und Beobachterentwurf
Die Theorie der Dissipativität als Beschreibung der Energiebilanz eines Systems eignet sich hervorragend für die Betrachtung dynamischer Systeme und deren Stabilitätseigenschaften. Dies wird deutlich durch die Fülle der in der Literatur vorhandenen Arbeiten, in welchen dissipativitätsbasierte Konzepte in unterschiedlicher Art verwendet werden.
Für den Entwurf von stabilisierenden Reglern können dabei oftmals physikalisch motivierte Energiekonzepte verwendet werden, was im Englischen zu dem Begriff des Energy shaping geführt hat. Des Weiteren können die klassischen Energiebegriffe abstrahiert werden und somit größere Systemklassen betrachtet werden, wie z.B. biologische Systeme, für welche keine direkte Analogie mittels mechanischer und chemischer Energiebegriffe möglich ist. Auf der Basis dieses allgemeinen Energiebegriffs besteht auch ein klarer Zusammenhang zur Stabilitätstheorie nach A. Lyapunov (1857-1918). Darüber hinaus können diese verallgemeinerten Energiekonzepte ebenfalls dazu genutzt werden die exponentielle Konvergenz des Schätzfehlers sogenannter Beobachter im Rahmen der modellbasierten Rekonstruktion von Systemzuständen auf der Basis gemessener Daten zu beweisen. Methodisch führen diese Ansätze auf Entwurfsverfahren, in welchen mittels der Lösung von Matrizenungleichungen die vorhandenen Entwurfsfreiheitsgrade und Verstärkungsfaktoren bestimmt werden.
In den letzten Jahren wurden erste Erweiterungen dieser Ansätze auf unendlich-dimensionale bzw. sogenannte verteilt-parametrische Systeme sowie vernetzte dynamische Systeme vorgeschlagen. Hierbei ist insbesondere zu bemerken, dass sich für örtlich verteilte Systeme die Frage nach der Positionierung von Sensoren und Aktoren ergibt, was zusätzliche Freiheitsgrade im Entwurf darstellt. Die Schwierigkeit insbesondere bei verteilt-parametrischen Systemen, welche mathematisch durch partielle (Integro-)Differenzialgleichungen beschrieben werden, liegt dabei in der Handhabung der nun auftretenden Operatorungleichungen, welche aus der Erweiterung der dissipativitätsbasierten Ansätze folgen. Es ist eine nicht-triviale Aufgabe Lösungsverfahren für diese Ungleichungen zu entwickeln und strukturelle Systemeigenschaften zu identifizieren, welche es ermöglichen allgemein gültige Ansätze zu formulieren.
In diesem Vortrag soll auf verschiedene, in den letzten Jahren entwickelte Ansätze für den dissipativitätsbasierten Regler- und Beobachterentwurf eingegangen und diese anhand anwendungsorientierter Beispiele illustriert werden.

Kurz-CV
Alexander Schaum ist seit April 2014 Wissenschaftlicher Mitarbeiter (Post-Doktorand) am Lehrstuhl für Regelungstechnik der Technischen Fakultät der Christian–Albrechts–Universität zu Kiel. Nach dem Vordiplom in Mathematik an der Universität Tübingen (2002) und dem Diplom in Technischer Kybernetik an der Universität Stuttgart (2006) hat er 2009 seine Promotion an der Universidad Nacional Autónoma de México (UNAM) in Mexiko-Stadt abgeschlossen, wofür er mit dem Preis der besten Promotion im Jahrgang 2009 am Institut für Ingenieurswissenschaften ausgezeichnet wurde. Von 2009 bis 2010 war er Post–Doktorand am Lehrstuhl für
Automatisierungstechnik der UNAM und von 2010 bis 2011 am Lehrstuhl für Verfahrenstechnik der Universidad Autónoma Metropolitana – Iztapalapa (UAM-I) in Mexiko Stadt. Von Juni 2011 bis März 2014 war er Gastprofessor am Lehrstuhl für Angewandte Mathematik und Informatik der Universidad Autónoma Metropolitana – Cuajimalpa (UAM-C) in Mexiko-Stadt.

Prof. Meurer

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Kolloquiumsvortrag: Dagmar Kainmüller, Max-Planck-Institut für molekulare Zellbiologie und Genetik / 22.01.16

22.01.2016 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, Übungsraum 2

Titel: Learning Deep Classifiers that integrate Prior Shape Knowledge for Bioimage Analysis


Abstract:

Deep Learning has rapidly transformed the field of computer vision in the past years. To date, deep convolutional neural networks (CNNs) outperform traditional machine learning approaches in a vast number of applications. However, little has been added to the theoretical understanding of CNNs since they have been proposed more than 25 years ago. Furthermore, huge sets of annotated data are necessary for successful training of deep CNNs, while image analysis tasks often come with small amounts of annotated data to learn from — especially in the context of applications in biology.

In this talk I will explore the theoretical relationship between CNNs and decision forests. Decision forests are a hugely popular machine learning tool that can be trained effectively in the face of small amounts of annotated data. They are widely used for image analysis tasks in biology. I will show that decision forests can be mapped to CNNs, which allows for developing novel, easily interpretable deep CNN architectures that can be trained from small amounts of data.

Prof. Carsten Meyer

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Kolloquiumsvortrag: Prof. Dr. Joachim Schnadt, Universität Lund, Schweden / 18.01.16

18.01.2016 von 17:15 bis 18:45

Institut für Materialwissenschaft, Kaiserstr. 2, 24143 Kiel, Geb. D Raum: "Aquarium"

Titel:  (Near-) Ambient pressure x-ray photoelectron spectroscopy: studying surface chemical processes under realistic conditions and in real time

 

Abstract:
Surface chemical processes play a ubiquitous role in our lives, whether this be in industrial catalytic processes, controlled oxide and metal growth processes of so great importance for e.g. the semiconductor industry, or chemical reactions in our bodies: surfaces are always involved. To investigate surface chemical processes there exists a large arsenal of surface-sensitive techniques, and among them many spectroscopies which can deliver elemental, chemical, and electronic information. However, in their conventional form most surface-sensitive spectroscopy techniques, such as x-ray photoelectron spectroscopy and x-ray absorption spectroscopy, are limited to vacuum environments, which prevents the study of ongoing surface chemical processes and which leads to decisive information being missed. Ambient pressure x-ray photoelectron spectroscopy has been adapted instrumentally to allow realistic or close-to realistic pressures and thus allows in situ and operando investigations of surface chemical processes. I will introduce the technique and present cases from the areas of atomic layer deposition (ALD) and chemical vapour deposition (CVD), aimed at gaining a true understanding of what is going on during the growth of oxide layers on semiconductors.

Prof. Selhuber-Unkel

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Kolloquiumsvortrag, Prof. Dr. Robert Huber, Inst. für Biomedizinische Optik, Uni Lübeck / am 16.01.2017

16.01.2016 von 17:15 bis 18:45

Technische Fakultät, Insitut für ET/IT, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Fourier Domain Modenkopplung

Abstract: Optical coherence tomography (OCT) is one of the biggest and fastest growing fields in optics. This new optical imaging modality is mainly used in biomedical applications, where it can provide depth resolved three-dimensional tissue contrast with micron scale resolution. One implementation of OCT requires rapidly wavelength swept, narrowband cw-laser light sources. Since the performance requirements of such OCT lasers substantially differ from classical tunable lasers, over the last ten years many groups have spent great effort on developing appropriate laser sources. Some of the best performing OCT light sources are the recently invented Fourier Domain mode locked (FDML) lasers, which enabled OCT depth scan rates well into the Multi-Megahertz range (MHz-OCT) for the first time. The talk will discuss the FDML mechanism, the related physics behind it, the involved laser technology, and various OCT imaging examples. Finally, recent results on using a FDML in combination with a new class of nanosecond fiber lasers for stimulated Raman sensing and two-photon imaging will be presented.

Prof. Dr. Martina Gernken

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Kolloquiumsvortrag: Prof. Dr. Jürgen Kurths - Institute of Physics, Humboldt Universität zu Berlin / 11.01.16

11.01.2016 von 17:15 bis 18:45

Institut für Elektrotechnik und Informationstechnik, Kaiserstr. 2, 24143 Kiel, Geb. D Raum: "Aquarium"

Titel:
Synchronization in Complex Networks and Its Stability: A Few Basics and some Applications

 

Abstract:

Synchronization phenomena are abundant in nature, science, engineering and social life, but it was first recognized by Christiaan Huygens in 1665 for coupled pendulum clocks; this was the beginning of nonlinear sciences. In the last two decades, this concept has been successfully extended to more complex systems, as the cardiovascular system or teleconnections in the climate system. Complex networks were firstly studied by Leonhard Euler in 1736 when he solved the Königsberger Brückenproblem. Recent research has revealed a rich and complicated network topology leading to interesting features of synchronization. Typical examples are the human brain, power grids, arrays of coupled lasers and the Amazon rainforest. A crucial problem is how stable synchronized regimes are in these systems against even large perturbations. Here we claim that the traditional linearization-based approach to stability is in several cases too local to adequately assess how stable a state is. Instead, we quantify it in terms of basin stability, a new measure related to the volume of the basin of attraction. This concept is applied to power grids, to investigate how a grid's degree of stability is influenced by certain patterns in the wiring topology. We mainly find that dead ends and dead trees strongly diminish stability. This will be discussed for the Northern European power system.

 

References: Pikovsky, A., M. Rosenblum, and J. Kurths, Synchronization – A Universal Concept in Nonlinear Sciences, Cambridge University Press 2001.

Arenas, A., A. Diaz-Guilera, J. Kurths, Y. Moreno, and C. Zhou, Phys. Reports 2008, 469, 93. P. Menck, J. Heitzig, N. Marwan, and J. Kurths, Nature Physics 9, 89 (2013)

P. Menck, J. Heitzig, J. Kurths, and H. Schellnhuber, Nature Commun. 5, 3969 (2014)

P. Schultz, J. Heitzig, and J. Kurths, New Journal Physics 16, 125001 (2014)

Y. Zou, T. Pereira, M. Small, Z. Liu, and J. Kurths, Phys. Rev. Lett. 112, 114102 (2014)

Prof. Kohlstedt

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Kolloquiumsvortrag, Dr. Seraphine Wegner, MPI Polymer-Forschung Mainz / am 09.01.2017

09.01.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Materialwissenschaft, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Photoswitchable linkers for cell and protein patterning

Abstract: Cell adhesion is regulated both in space and time during many biological processes such as embryogenesis, wound healing, cancer invasion and tissue formation. Therefore, it is of great importance to develop platforms to reversibly control cell interactions in vitro and in vivo non-invasively and with high precision. Light is the ideal switch towards this goal as it is in general considered biorthogonal and allows for very  high spatial and temporal control.  Here, we report a number of platforms that allow controlling cell-surface interactions with light to guide cell adhesion and behavior based on photocleavable nitrobenzene analogues and light responsive proteins. We attach these light responsive molecules specifically to PEG coated surfaces and are able to cleave off the presented functionality or attach it to the surface upon illumination with light. In micropatterning cRGD on these surfaces, we can control the cell adhesions and prevent cell attachment to specific regions on the substrate. Similarly, we can controllably present proteins of interest on such surfaces with any micropattern. These newly developed light responsive platforms, offer great flexibility to microstructure interphases with different functional molecules and control cell-surface interactions with great precision.

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Kolloquiumsvortrag: Prof. Gabriella Andersson, Uppsala University, Schweden / 14.12.15

14.12.2015 von 17:15 bis 18:45

Institut für Materialwissenschaften, Kaiserstr. 2, Geb. D Raum: "Aquarium"

Titel:
Optimizing magnetic properties in the Materials Physics division at Uppsala University

 

Abstract:

After a brief introduction to Uppsala University in general, there will be an overview of the research activitiy in the Materials Physics division in the Department of Physics and Astronomy. Our main three fields are Magnetism, Soft Matter, and Hydrogen in Metals, and they all rely on in-house synthesis of materials and a continuous chain of subsequent experiments, from our own laboratories to large international facilities. Since we have control from the beginning to the end, we can find physical mechanisms behind the properties we observe, and thus gain tools for optimizing the materials further, e.g. through composition and placement of atoms.

After this review, I will present some more specific examples of my research projects, which concern optimization of magnetic properties in metallic thin films and multilayers. The common theme is tuning of magnetic anisotropy by composition and structure, and the materials are either amorphous rare-earth-transition-metal compounds or epitaxial, i.e. crystalline, multilayers where strain states are used as an additional tuning possibility.

Prof. Selhuber-Unkel

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Kolloquiumsvortrag: Prof. Dr. Oleg Lupan, Technical University of Moldova / 30.11.15

30.11.2015 von 17:15 bis 18:45

Institut für Materialwissenschaft, Kaiserstr. 2, 24143 Kiel, Geb. D, Raum: "Aquarium"

Titel:

Nanostructuring semiconducting oxides for nanodevices

 

Abstract:

Development of multifunctional nanosensors based on new advanced functional nano-materials is in the focus of the research community nowadays, since it is one of the largest and fastest evolving market segment, with revenues expected to surpass several trillion Euros soon. Scientific research on nano-materials contributes to miniaturization and improvements in the size, detection range, reliability, selectivity and sensitivity of existing solid-state sensors and light/image detectors, which are the key components of many electronic and optoelectronic circuits. Nanodevices which can perform multiple tasks are of high demand for intelligent portable devices with small sizes (e.g. smartphones with environmental sensors) and other applications (ranging from high-capacity information storage to biochemical sensing, chemical and biological analysis, and astronomy) due to very low power consumption and improved performances.

Thus, research on semiconducting oxide nanocrystals will likely remain one of the leading topics in condensed matter physics and advanced functional materials science for many years. Looking beyond this field, nanostructuring nanocrystal systems based on single or mixed phases of oxides have been assembled into designer structures in a precisely chosen sequence. This creates opportunities to study novel electrical, physical, and sensorial phenomena followed by implementation in nanodevice applications which are not possible with ordinary bulk materials and classical technologies.

In this talk, an overview across the field of semiconducting oxides will be given, namely nano-ZnO, CuO, SnO2, MoO3, and their nanostructuring by different nanotechnological approaches, which can be scaled-up to industrial scale. The challenges to employ the properties of semiconducting oxides on practical application grounds will be discussed and strategies will be outlined for their fabrication, characterization, and nanodevice integration by bottom-up technologies. Integration and applications in the single nanowire, nanorod, tripod, and tetrapod as sensing devices and in special as multifunctional nanosensors will also be discussed.

Furthermore, the contribution of crystalline nanosensing and nanophotonical systems will be emphasized to act as an enabling technology for scientific achievements in other research fields.

In this talk, semiconducting oxides as main nano-blocks for nanodevices, namely our contribution to building a new road to nanodevices from top-down to bottom-up to hybrid nanotechnologies will be discussed.

Prof. Adelung

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Kolloquiumsvortrag: Dr. Sanjeev Kumar Srivastava, Indian Institute of Technology, Kharagpur, India / 23.11.15

23.11.2015 von 17:15 bis 18:45

Institut für Materialwissenschaften, Kaiserstr. 2, 24143 Kiel, Geb. D, Raum: "Aquarium

Titel:  Microscopic and macroscopic studies of electron correlations in solids

 

Abstract:

Electron correlations determine or influence almost all aspects of solid state properties, be it electrical transport, magnetic and superconducting properties, or even more complex strong electron correlation based phenomena. The study of electron correlations, thus, occupies a key position in the central theme of current experimental and theoretical research in condensed matter physics. There are two basic ways to investigate electron correlations: (i) studies of macroscopic properties, which basically constitute a report on the ensemble- and time-averaged behaviour of the solid, and (ii) microscopic investigations, which essentially provide an explanation to the macroscopic behaviour. The microscopic measurements are performed at very short length (~ 1 - 10 nm) and time (fs - ns) scales. An extremely useful microscopic technique is the observation of perturbation, produced by the interactions between the crystal electromagnetic fields and nuclear electromagnetic moments, of the angular anisotropic distribution of the intensity of γ-rays emitted by a radioactive nucleus produced in a heavy ion induced fusion evaporation reaction and subsequently implanted into the solid. The technique is known as Time-Differential Perturbed Angular Distribution (TDPAD). It is further desirable always to compliment the experimental results with first-principles density functional theory (DFT).

 

This talk will begin with short descriptions of the basic principles of the microscopic TDPAD technique and the DFT. Subsequently, a brief overview of the following electron correlation based representative results will be presented: (i) spin fluctuations of Fe in dilute Pd alloys [1], (ii) defect induced magnetism in HOPG [2], (iii) Fe hyperfine field in the pnictide superconductor CaFe2As2 [3], and (iv) 3d impurities in Cr [4]. In addition, a recent macroscopic study on quantum phase transitions in Pd-Ni nanoalloys [5] will also be discussed.

References:

1.  S.K. Srivastava,S.N. Mishra and G.P. Das,J. Phys.: Cond. Matter 18 (2006) 9463.

2.  S.K. Mohanta, S.N. Mishra, S.M. Davane, and S.K. Srivastava, J. Phys.: Cond. Matter 24 (2012) 085601.

3.  S.K. Mohanta, S.N. Mishra, S.M. Davane,  N. Kumar, A. Thamizhavel, S. Layek, Z. Hussain and S.K. Srivastava, Nucl. Instr. Meth. Phys. Res. B 299 (2013) 71.

4.  S.N. Mishra and S.K. Srivastava, J. Phys.: Cond. Matter 20 (2008) 285204.

P. Swain, S.K. Srivastava and S.K. Srivastava, Phys. Rev. B 91 (2015) 045401.


Prof. Adelung

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Kolloquiumsvortrag: Prof. Dr. José Claudio Verschae, Pontifica Universidad Católica de Chile / 30.10.15

30.10.2015 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, Übungsraum 2

Titel: Online Machine Covering: Exploiting Symmetries to Control Migration

Abstract:

Load balancing in parallel machines is a fundamental problem that has been studied extensively in the literature. We consider a version where jobs are revealed online one by one.  Our aim is to assign the jobs to a given number of machines in order to balance the load, more specifically, to maximize the load of the least loaded machine. In the classic online model decisions are irrevocable, which is unrealistic for several applications.

We consider a relaxed version proposed by Sanders et al., where a limited amount of jobs can be reassigned at the arrival of a new job. We are interested in understanding the trade-off between the quality of solutions and the amount of migrated jobs. In this talk I will introduce the problem and basic techniques. Then I will focus on the analysis of a simple greedy algorithm. Our main observation is that well chosen small perturbations of the processing times creates several types of symmetries in the solutions. This implies that solutions that are a priori very different are actually equivalent modulo these symmetries. We show how this property can be exploited algorithmically in order to find good solutions that are similar after the arrival of new jobs, thus yielding improved algorithms for this problem.

This is joint work with Waldo Galvez and Jose Soto.

Prof. Jansen

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Kolloquiumsvortrag: Dr. Ronald Kriemann, Max-Planck-Institut f. Mathem. i. d. Naturwissensch., Leipzig / 22.10.15

22.10.2015 von 13:30 bis 16:00

Institut für Informatik, Christian-Albrechts-Platz 4, 24118 Kiel, Hochhaus, Raum 1304a

Titel: H-Arithmetic for Many-Core Systems

 

Abstract:
Classical arithmetic for hierarchical matrices, e.g. matrix multiplication or LU factorization, is based on recursive algorithms on local matrix blocks. Due to the local scope, this formulation may introduce additional dependencies between the actual computational tasks. This significantly limits the parallel speedup of the arithmetic on modern many-core systems. An alternative formulation of the arithmetic is described, which overcomes these limitations by explicitly defining computational tasks and their dependencies on a global scope. Furthermore, tasks and dependencies form a directed acyclic graph, which can be used for scheduling tasks onto processors. Numerical examples will demonstrate the effectiveness of this new approach.

Prof. Börm

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Kolloquiumsvortrag: Prof. Joachim Holtz, Life IEEE Fellow, University of Wuppertal / 19.10.15

19.10.2015 von 17:15 bis 18:45

Institut Elektrotechnik und Informationstechnik, Kaiserstr. 2, 24143 Kiel, Geb. D Raum: "Aquarium""

Titel: Reducing IGBT Switching Losses by Gate Charge Control

Abstract:
IGBTs are voltage controlled switching devices. Their fast switching characteristics
generate high voltage gradients which stress the motor winding insulation and generate
undesired bearing currents in ac drive systems. Electromagnetic interference may happen
with other electronic apparatus. Also the current gradients are high. They increase the diode
turn-off losses by generating high reverse recovery currents.
Voltage gradients are conventionally reduced by feeding the gate control signals through
resistors. The IGBT gate capacitance then delays the gate voltage changes, and thus increases
the transition intervals between switching states at the expense of higher switching losses.
The existing drawbacks are overcome by controlling the gate charge gradients at turn-on and
turn-off, thereby enforcing predetermined values of dv/dt and di/dt. Nonlinear dynamic IGBT
properties are accounted for. The gate charge profiles versus time are made dependent on the
particular load current value at switching, and on the internal device capacitances. These
incur rapid changes during the switching process under the influence of the device voltage
waveforms. Experiment results using 6.6 kV / 400 Amp IBGTs show that dv/dt is reduced
from 4 kV to 1 kV/ms while switching losses reduce to 70%.

About the Speaker
Joachim Holtz graduated in 1967 and received the Ph.D. degree in 1969 from the Technical
University Braunschweig, Germany.
In 1969 he became Associate Professor and, in 1971, Full Professor and Head of the Control
Engineering Laboratory, Indian Institute of Technology in Madras, India. He joined the
Siemens Research Laboratories in Erlangen, Germany, in 1972. From 1976 to 1998, he was
Professor and Head of the Electrical Machines and Drives Laboratory, Wuppertal University,
Germany. He is presently Professor Emeritus and a Consultant.
Dr. Holtz has extensively published, among others 12 invited papers in journals. He has
earned 15 Prize Paper Awards. He is the coauthor of seven books, and holds 33 patents.
Dr. Holtz is the recipient of the IEEE Industrial Electronics Society Dr. Eugene Mittelmann
Achievement Award, the IEEE Industrial Applications Society Outstanding Achievement
Award, the IEEE Power Electronics Society William E. Newell Field Award, the IEEE Third
Millennium Medal, the Anthony J. Hornfeck Service Award, and the IEEE Lamme Gold
Medal. He is a Life Fellow of the IEEE.
Dr. Holtz is Past Editor-in-Chief of the IEEE Transactions on Industrial Electronics, Distinguished
Lecturer of the IEEE Industrial Applications Society and IEEE Industrial Electronics
Society.

Prof. Liserre

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Sonderkolloquium Prof. Dr. Oliver G. Schmidt, IFW Dresden, 07.08.2015

07.08.2015 von 14:00 bis 15:30

Insitut für Materialwissenschaft, Kaiserstraße 2, 24143 Kiel, Aquarium

Titel: 3D nanomembrane architectures: From lab-in-a-tube systems to micro-biorobotics

 

Abstract:

Nanomembranes are thin, flexible, transferable and can be shaped into 3D micro- and nanoarchitec-tures. This makes them attractive for a broad range of applications and scientific research fields ranging from novel hybrid heterostructure devices to ultra-compact 3D systems both on and off the chip. If na-nomembranes are differentially strained they deform themselves and roll-up into tubular structures upon release from their mother substrate. Rolled-up nanomembranes can be exploited to rigorously compact electronic circuitry, energy storage units and novel optical systems. They can also serve as ideal plat-form to study single cell behaviour in 2D confined systems.

If appropriate materials are chosen, rolled-up tubes act as tiny catalytic jet engines which in the ultimate limit may drive compact multifunctional autonomous systems for medical and environmental applica-tions. If magnetic tubes are combined with flagella-driven sperm cells, such hybrid micro-biorobots offer new perspectives towards artificial reproduction technologies.

 Key References:
1. Nature 410, 2001, 168-168.
2. Advanced Materials 13, 2001, 756-759.
3. Advanced Materials 20, 2008, 4085-4090.
4. Lab on a Chip 9, 2009, 263-268.
5. Nature Materials 9, 2010, 491-495.
6. Nature Nanotechnology 5, 2010, 458-464.
7. Angewandte Chemie 125, 2013, 2382-2386.
8. ACS nano 7, 2013, 9611-9620.
9. Advanced Functional Materials 25, 2015, 2763-2770.
10. Advanced Materials 27, 2015, 1274-1280

 

 

 

Prof. Adelung

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Sonderkolloquium: Prof. Nicola Femia -University of Salerno / 20.07.2015

20.07.2015 von 10:30 bis 12:00

Institut für Elektrotechnik und Informationstechnik, Kaiser Str. 2, Geb.C , Raum "Aquarium"

Titel: Power Magnetics and Wireless Power


Abstract:

Power magnetics and wireless power are hot topics in modern power management technologies. Power Magnetic devices are in the focus when dealing with high-power-density issues, as power inductors and transformers have a strong influence on the efficiency and size of power converters. Wireless Power is the emerging technology that simplifies battery charging systems and is of great impact in several pervasive applications, such as automotive and portable/wearable devices. The lecture will provide an overview of the most recent research activities of the Power Electronics Research Group of Salerno University about models, mehods, design and optimization topics rearding Power Magnetics and Wireless Power.

Prof. Liserre

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Kolloquiumsvortrag: PD Dr. Frank Gurski - Universität Düsseldorf/ 17.07.2015

17.07.2015 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, Übungsraum 2

Titel: Knapsack Problems: A Parameterized point of view

 

Abstract:

 

The knapsack problem is a very famous NP-hard problem in combinatorial optimization. In the 0-1 knapsack problem (0-1 KP) we are given a set A of n items. Every item j has a profit p(j) and a size s(j). Further there is a capacity c of the knapsack. The task is to choose a subset A' of A, such that the total profit of A' is maximized and the total size of A' is at most c.

Within the d-dimensional 0-1 knapsack problem (d-KP) a set A of n items and a number d of dimensions is given. Every item j has a profit p(j) and for dimension i the size s(i,j). Further for every dimension i there is a capacity c(i). The goal is to find a subset A' of A, such that the total profit of A' is maximized and for every dimension i the total size of A' is at most the capacity c(i).

Further we consider the multiple 0-1 knapsack problem (MKP) where beside n items a number m of knapsacks is given. Every item j has a profit p(j) and a size s(j) and each knapsack i has a capacity c(i). The task is to choose m disjoint subsets of A such that the total profit of the selected items is maximized and each subset can be assigned to a different knapsack i without exceeding its capacity c(i) by the sizes of the selected items.

Since d-KP and MKP are defined on inputs of various informations, we study the fixed-parameter tractability of these problems. The idea behind fixed-parameter tractability is to split the complexity into two parts - one part that depends purely on the size of the input, and one part that depends on some parameter of the problem that tends to be small in practice. We discuss the following parameters: the number of items, the threshold value for the profit, the sizes, the profits, the number d of dimensions, and the number m of knapsacks.

We also consider the connection of parameterized knapsack problems to linear programming, approximation, and pseudopolynomial algorithms.

Prof. Jansen

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Kolloquiumsvortrag: PD Dr. Frank Gurski - Universität Düsseldorf/ 17.07.2015

17.07.2015 von 14:15 bis 15:45

Institut für Informatik, Ludewig-Meyn-Str. 2, Übungsraum 2

Titel: Knapsack Problems: A Parameterized point of view

 

Abstract:

 

The knapsack problem is a very famous NP-hard problem in combinatorial optimization. In the 0-1 knapsack problem (0-1 KP) we are given a set A of n items. Every item j has a profit p(j) and a size s(j). Further there is a capacity c of the knapsack. The task is to choose a subset A' of A, such that the total profit of A' is maximized and the total size of A' is at most c.

Within the d-dimensional 0-1 knapsack problem (d-KP) a set A of n items and a number d of dimensions is given. Every item j has a profit p(j) and for dimension i the size s(i,j). Further for every dimension i there is a capacity c(i). The goal is to find a subset A' of A, such that the total profit of A' is maximized and for every dimension i the total size of A' is at most the capacity c(i).

Further we consider the multiple 0-1 knapsack problem (MKP) where beside n items a number m of knapsacks is given. Every item j has a profit p(j) and a size s(j) and each knapsack i has a capacity c(i). The task is to choose m disjoint subsets of A such that the total profit of the selected items is maximized and each subset can be assigned to a different knapsack i without exceeding its capacity c(i) by the sizes of the selected items.

Since d-KP and MKP are defined on inputs of various informations, we study the fixed-parameter tractability of these problems. The idea behind fixed-parameter tractability is to split the complexity into two parts - one part that depends purely on the size of the input, and one part that depends on some parameter of the problem that tends to be small in practice. We discuss the following parameters: the number of items, the threshold value for the profit, the sizes, the profits, the number d of dimensions, and the number m of knapsacks.

We also consider the connection of parameterized knapsack problems to linear programming, approximation, and pseudopolynomial algorithms.

Prof. Jansen

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Sonderkolloquium Prof. Manfred Wuttig, University of Maryland, College Park, MD, 17.07.2015

17.07.2015 von 10:00 bis 11:30

Institut für Materialwissenschaft, Kaiserstraße 2, 24143 Kiel, Aquarium

Titel: Unusual Magneto-Elasticity of Fe-(Co), Ga, (Al, Ge, Si) Alloys

 

Abstract:
The magneto-elasticity of  BCC Fe-Ga,Al,Ge solid solutions has been widely discussed during the last decade. In this talk we summarize it and show how the unique linear, reversible and isotropic magnetic characteristics represent the response of a magneto-elastically adaptive state.

 

Prof. Quandt

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Kolloquiumsvortrag: Dr. Stephan Warnat/ Dalhousie University, Halifax, Canada / 13.07.2015