A new method to enclose the pseudospectrum via the numerical range
of the inverse of a matrix or linear operator is presented. The method is
applied to finite-dimensional discretizations of an operator on an infinite-
dimensional Hilbert space, and convergence results for different approxi-
mation schemes are obtained, including finite element methods. We show
that the pseudospectrum of the full operator is contained in an inter-
section of sets which are expressed in terms of the numerical ranges of
shifted inverses of the approximating matrices. The results are illustrated
by means of two examples: the advection-diffusion operator and the Hain-
Lüst operator.

arXiv: http://arxiv.org/abs/2004.12790

The German Research Foundation (DFG) is financing a research project on the particular challenges arising in many-objective optimization, where more than two conflicting objective functions are considered simultaneously. Such objective functions can model ecological and economical criteria, the quality, reliability and cost of a technical structure, or the travel time, travel cost and convenience in routing applications. The focus lies in combinatorial problems like multiobjective knapsack problems, multiobjective assignment problems, and multiobjective network optimization problems including shortest path and spanning tree problems.

The complexity of multiobjective combinatorial optimization problems largely depends on the number of considered objective functions. In this project, the geometrical and combinatorial structure of the Pareto set, i.e., the set of all those solutions that can not be improved in one objective without deterioration in at least one other objective, will be used to achieve a new level of understanding for higher-dimensional problems. This includes the determination of concise representations of the search area and of representative subsets as well as the analysis of different preference structures and quality indicators.

October 5-7, 2020

The international scientific event aims to gather active researchers working in the field of infinite-dimensional control theory and its applications with the focus on stability, stabilization and control problems. The main objective is to present most recent research results in this area and discuss them during the workshop as well as to speak about open problems in this emerging research direction. Another objective is to establish and / or maintain international collaborations in this research field. Moreover, this workshop will contribute to the visibility of the corresponding research activities of German scientists establishing them as one of the worldwide leading communities in this research area.

Each morning there will be five invited plenary talks. A list of the invited plenary speakers with titles of their talk can be found in the appendix. In the afternoon there will be time slots for 8-24 talks (in probably parallel sessions) depending on the number of applications for the workshop and a poster session. Interested participants will be encouraged to register for the workshop and apply for a presentation by May 31, 2020.

The workshop is funded by the DFG.

Organisers: Sergey Dashkovskiy (Universität Würzburg), Birgit Jacob (Universität Wuppertal), Andrii Mironchenko (Universität Passau) and Fabian Wirth (Universität Passau)

More information

Das im Konsortium RoboFlex Turbo bewilligte Projekt "Mikrostukturelle Analysen der Entstehung von Schädigung bei realistischen Lastszenarien" erforschet die physikalischen Ursachen für die starke, statistische Schwankung der Lebensdauer mechanischer Komponenten. Hier wird auf Basis der zufälligen Anordnung von Mikrostukturen in Nickelbasis-Superlegierungen die Streuung der Lebensdauer mit einem Multiskalenansatz modelliert. Fördergeber sind Siemens und das BMWi. Projektpartner für die experimentellen Arbeiten ist der Lehrstuhl für Werkstoffkunde and der TU Kaiserslautern (Prof. T. Beck).

Die Forschungsvereinigung Verbrennungsmotoren fördert das Projekt "Anwendung und Vergleich von Modellen zur Lebensdaueranalyse von Hochtemperaturbauteilen unter Kriechermüdung auf Basis fortschrittlicher probabilistischer Methoden" quantifiziert die Unsicherheit in Hochparametrischen, konstitutiven Modellen der Kriechermüdung. Ebenfalls sollen optimalen an- und Abfahrprozesse untersucht werden, mit denen Hochtemperaturanlagen, wie z.B. Turbinen, möglichst schonend in Betrieb genommen oder abgeschaltet werden können. Hier arbeiten die Wissenschaftler*innen mit dem IfW/MPA in Darmstadt (Dr. Kontermann) zusammen.

Insgesamt wurden Mittel von 310.000 EUR für die BUW eingeworben.

Pressemitteilung

Reliable simulation of pedestrian movement is essential for security aware design of buildings and infrastructure. Routing decisions of users significantly influence the effectiveness of a pedestrian infrastructure. However, the modelling of path selection is due to uncertainty and can even in evacuation scenarios not be completely controlled. HyDEFS is an event-driven dynamic flow simulation software which is designed to simulate pedestrian movement depending on varying routing decisions of the individual users and varying constraints. HyDEFS uses given density depending velocities to model congestions and evaluates flow distributions with respect to average and maximum travel time.

We consider in this article rather simple scenarios such that the simulation results can be validated analytically. On a small network the discrete and the time-continuous calculation yield almost the same optimal solutions (minimizing
average evacuation time and maximal evacuation time, respectively) as the simulation with HyDEFS.

Klamroth, K., Lang, B., Seyfried, A., & Stiglmayr, M. (2020). Network Simulation for Pedestrian Flows with HyDEFS. Collective Dynamics, 5, 1-16. doi:http://dx.doi.org/10.17815/CD.2020.24

Die Fachkollegien der Deutschen Forschungsgemeinschaft (DFG) bewerten Anträge auf finanzielle Förderung von Forschungsvorhaben. Sie kontrollieren dabei auch die Wahrung einheitlicher Maßstäbe bei der Begutachtung und werden bei Fragen der Weiterentwicklung sowie Ausgestaltung der DFG-Förderprogramme zu Rate gezogen. Im Oktober und November wurden die Vertreter*innen der Fachkollegien neu gewählt. Nun steht das endgültige Ergebnis fest: Unter den Gewählten sind auch drei Wissenschaftler*innen der Bergischen Universität Wuppertal.

Von der Bergischen Universität in eines der insgesamt 49 Fachkollegien gewählt wurden:

• Prof. Dr. Gerald Hartung, Philosophie mit Schwerpunkt Kulturphilosophie/Ästhetik: Fachkollegium Geschichte der Philosophie
• Prof. Dr. Birgit Jacob, Arbeitsgruppe Funktionsanalysis: Fachkollegium Mathematik
• Prof. Dr. Thomas Riedl, Lehrstuhl für Elektronische Bauelemente: Fachkollegium Elektronische Halbleiter, Bauelemente und Schaltungen, Integrierte Systeme

Pressemitteilung

Doctoral students in applied mathematics started a SIAM Student Chapter at the University of Wuppertal. The aim of the SIAM Student Chapter Wuppertal is to unite both graduate and undergraduate students with an interest in computational and applied mathematics. The chapter organizes local meetings on subjects of interest, including seminars by students and faculty of the University of Wuppertal, as well as invited speakers from other institutions, excursions to industry sites, and workshops on different topics in applied mathematics and beyond. The Society for Industrial and Applied Mathematics (SIAM) provides funds to support activities of the student chapter.

Website of the SIAM Student Chapter Wuppertal: https://siamchapter.uni-wuppertal.de

Mit rund 1,1 Millionen Euro fördert das Bundesministerium für Wirtschaft und Energie (BMWi) ein neues Forschungsvorhaben zum Thema Künstliche Intelligenz (KI) an der Bergischen Universität Wuppertal: Im Rahmen des Projekts „KI-DeltaLearning“ erforschen die drei Wissenschaftler Dr. Matthias Rottmann, Dr. Karsten Kahl (beide Angewandte Informatik) und Prof. Dr. Hanno Gottschalk (Arbeitsgruppe Stochastik) die Übertragbarkeit von KI-Algorithmen bei sich verändernden Bedingungen. Das Verbundprojekt, angesiedelt in der Fakultät für Mathematik und Naturwissenschaften, ist Teil der KI-Leitinitiative des Verbandes der Deutschen Automobilindustrie (VDA).

Pressemitteilung

The IMACM-Juniors seminar trip took place from 11th to 13th February in Schmallenberg. The aim of the seminar was to bring the PhD students of the different working groups together. 15 Participants (14 PhD students, 1 Post Doc) of four different working groups of IMACM presented their research in the beautifully located seminar house. Furthermore, there was time to discuss research topics and general questions regarding the dissertation. In the evenings there was time for socializing while cooking together and playing board games.

Dr. Matthias Ehrhardt, Professor für Angewandte Mathematik und Numerische Analysis an der Bergischen Universität Wuppertal, wird in den kommenden vier Jahren der Vertreter Deutschlands im Council des „European Consortium for Mathematics in Industry“ (ECMI) sein.

Pressemittelung