Applied and Computational Mathematics (ACM)

Computational Magnetics

Many electro-technical devices such as e.g. printed circuit boards, electrical drives and antenna systems can be simulated on the basis of electrical circuits. However, the increasing frequencies and the decreasing size force designers to account for wave propagation effects, eddy-current effects, ferromagnetic saturation and hysteresis. For wave propagation effects and eddy-current effects, the results of stand-alone field simulation can be represented by an order-reduced equivalent model, which is then inserted in the overall circuit model. The representation of field-dependent nonlinearities and hysteresis effects, however, is not straightforward.

2D Simulation of a Transformer

2D Simulation of a Transformer

The coupled field and circuit simulation becomes troublesome when a large number of time steps is required. This occurs when e.g. simulating an electrical drive where the machine requires 10 periods of 50 Hz to reach nominal speed whereas the switching of the Insulated Gate Bipolar Transistors in the frequency converter switches at 20 kHz, necessitating a time steps in the order of a microsecond to be used in the simulation. Since the field model consists typically of a few million degrees of freedom, all those unknowns have to be solved in every time step. Fortunately, the relevant time constants in electrical-energy converter are in the range 50 Hz. Hence the field model does not have to be time-stepped at the same rate as the circuit model, in which fast switches are present. The use of adaptive multirate time-integration schemes can reduce the numerical complexity of the problem substantially.

Research Questions

Cooperation

Former and ongoing projects

Publications



2025

5475.

Khosrawi-Rad, Bijan; Keller, Paul; Grogorick, Linda; Benner, Dennis; Janson, Andreas; Robra-Bissantz, Susanne
Let's Play with AI! A 2x2 Experiment on Collaborative vs. Competitive Game Elements for Pedagogical Conversational Agents
Pre-ICIS SIG Services Workshop on Synergizing Service Ecosystems with AI
Bangkok, Thailand
2025

5474.

Schmitz, Denise
LinkedIn-Posts zur Jahrestagung
Nachhaltige IT und Alternativen zu Big Tech, 49
2025
Herausgeber: Gesellschaft für Informatik e.V.

5473.

[german] Cornelius, Soraya; Bohrmann-Linde, Claudia
Motivieren mit (Teil-)Aufgaben zur Erklärvideoproduktion im Chemieunterricht
In Johannes Huwer, Timm Wilke, Amitabh Banerji, Editor, Band Progress in Digitalisation in Chemistry Education 2024. Digitales Lehren und Lernen an Hochschule und Schule im Fach Chemie
Seite 37-42
Herausgeber: Waxmann-Verlag, Münster New York
2025
37-42

ISBN: 978-3-8188-0042-0

5472.

Finster, Rebecca; Grogorick, Linda; Robra-Bissantz, Susanne
Navigation im Cyberraum: Die NIS2-Umsetzung in der öffentlichen Verwaltung - mit KOMPASS und SEXTANT
Fachtagung Rechts- und Verwaltungsinformatik (RVI)
Hamburg
2025

5471.

Schweitzer, Marcel
Near instance optimality of the Lanczos method for Stieltjes and related matrix functions
SIAM J. Matrix Anal. Appl., 46 :1846-1865
2025

5470.

Bolten, Matthias; Doganay, Onur Tanil; Gottschalk, Hanno; Klamroth, Kathrin
Non-convex shape optimization by dissipative Hamiltonian flows
Engineering Optimization, 57 :384--403
2025

5469.

Beck, Christian; Jentzen, Arnulf; Kleinberg, Konrad; Kruse, Thomas
Nonlinear Monte Carlo Methods with Polynomial Runtime for Bellman Equations of Discrete Time High-Dimensional Stochastic Optimal Control Problems
Appl. Math. Optim., 91 (1) :26
2025

5468.

Arlinghaus, Clarissa Sabrina; Schmitz, Denise
NRW vernetzt sich – Neue Regionalgruppe Frauen und Informatik gestartet
Nachhaltige IT und Alternativen zu Big Tech, 49
2025
Herausgeber: Gesellschaft für Informatik e.V.

5467.

Abel, Ulrich; Acu, Ana Maria; Heilmann, Margareta; Raşa, Ioan
On some Cauchy problems and positive linear operators
Mediterranean Journal of Mathematics, 22
2025

5466.

Figueira, José Rui; Klamroth, Kathrin; Stiglmayr, Michael; Sudhoff Santos, Julia
On the Computational Complexity of Multi-Objective Ordinal Unconstrained Combinatorial Optimization
Operations Research Letters :107302
2025

5465.

Löhken, Lara; Stiglmayr, Michael
On the multiobjective cable-trench problem
Journal of Combinatorial Optimization, 49 (55)
2025

5464.

Lorenz, Jan; Zwerschke, Tom; Günther, Michael; Schäfers, Kevin
Operator splitting for coupled linear port-Hamiltonian systems
Applied Mathematics Letters, 160 :109309
2025
Herausgeber: Elsevier

5463.

Lorenz, Jan; Zwerschke, Tom; Günther, Michael; Schäfers, Kevin
Operator splitting for coupled linear port-Hamiltonian systems
Applied Mathematics Letters, 160 :109309
2025
Herausgeber: Elsevier

5462.

Sinani, Mario; Wynn, Andrew; Palacios, Rafael
Physics-Informed Data-Driven Modelling of Nonlinear Aerodynamic Forces of the Pazy Wing
AIAA SciTech Forum, 6-10 January
Januar 2025

5461.

Vinod, Vivin; Lyu, Dongyu; Ruth, Marcel; R. Schreiner, Peter; Kleinekathöfer, Ulrich; Zaspel, Peter
Predicting Molecular Energies of Small Organic Molecules With Multi-Fidelity Methods
J. Comp. Chem., 46 (6) :e70056
2025

5460.

[german] Zeller, Diana; Bohrmann-Linde, Claudia; Mack, Nils; Schrader, Claudia
Produktion eigener VR-Lernsettings im Projekt FoPro-VR. Ein interdisziplinärer Lehransatz für die Lehramtsausbildung
In Mrohs, Lorenz; Franz, Julia; Herrmann, Dominik; Lindner, Konstantin; Staake, Thorsten, Editor, Digitales Lehren und Lernen an der Hochschule. Strategien - Bedingungen - Umsetzung
Seite 191-204
Herausgeber: transcript, Bielefeld
2025
191-204

ISBN: 9783839471203

5459.

Khosrawi-Rad, Bijan; Keller, Paul; Benner, Dennis; Grogorick, Linda; Borchers, Arne; Janson, Andreas; Leimeister, Jan Marco; Robra-Bissantz, Susanne
Promoting Students’ Motivation in Language Education with Gamified Pedagogical Conversational Agents
Computers & Education, 238 :1–24
2025

5458.

Vinod, Vivin; Zaspel, Peter
QeMFi: A Multifidelity Dataset of Quantum Chemical Properties of Diverse Molecules
Sci. Data, 12 (1) :202
2025
Herausgeber: Nature Publishing Group
ISSN: 2052-4463

5457.

Patel, Vivak; Maldonado, D Adrian; Melnichenko, Maksim; Pritchard, Nathaniel; Rao, Vishwas; Rebrova, Elizaveta; Sankararaman, Sriram; Schweitzer, Marcel
Scientific Applications Leveraging Randomized Linear Algebra
2025

5456.

Clément, François; Doerr, Carola; Klamroth, Kathrin; Paquete, Luís
Searching Permutations for Constructing Uniformly Distributed Point Sets
Proceedings of the National Academy of Sciences, 122 (14) :e2424464122
2025

5455.

Palitta, Davide; Schweitzer, Marcel; Simoncini, Valeria
Sketched and truncated polynomial Krylov methods: Evaluation of matrix functions
Numer. Linear Algebra Appl., 32 :e2596
2025

5454.

Schmitz, Denise
Sketchnote zur Jahrestagung
Nachhaltige IT und Alternativen zu Big Tech, 49
2025
Herausgeber: Gesellschaft für Informatik e.V.

5453.

Santos, Daniela Dos; Klamroth, Kathrin; Martins, Pedro; Paquete, Luís
Solving the Multiobejctive Quasi-Clique Problem
European Journal of Operational Research, 323 :409—424
2025

5452.

Gökkus, Yasemin
Spieleentwickung im Chemieunterricht. Auftakt einer Aktionsforschung
MNU-Journal, 03/2025 :182-190
2025

5451.

Hamadi, Majed; Mahdavi-Amiri, Nezam; Schweitzer, Marcel
Splitting methods based on the nonzero diagonal pattern for computing matrix functions
2025