Mathematik und Informatik

Prof. Dr. Christian Engwer, Angewandte Mathematik Münster: Institut für Analysis und Numerik

Investigator in Mathematics Münster
Field of expertise: Numerical analysis, machine learning, scientific computing

Private Homepagehttps://www.uni-muenster.de/AMM/engwer/team/engwer.shtml
Research InterestsNumerical methods for partial differential equations
Scoientific Computing
High-Performance Computing
Design and development of numerical software
Cut-cell methods
Numerical methods for surface PDEs and geometric PDEs
Biomedical Applications
Topics in
Mathematics Münster


T9: Multi-scale processes and effective behaviour
T10: Deep learning and surrogate methods
Current PublicationsEngwer, Christian; Ohlberger, Mario; Renelt, Lukas Model order reduction of an ultraweak and optimally stable variational formulation for parametrized reactive transport problems. SIAM Journal on Scientific Computing Vol. 46 (5), 2024 online
Engwer,Christian; Ohlberger, Mario; Renelt, Lukas Construction of local reduced spaces for Friedrichs' systems via randomized training. , 2024 online
Medani, Takfarinas; Garcia-Prieto, Juan; Tadel, Francois; Antonakakis, Marios; Erdbrügger, Tim; Höltershinken, Malte; Mead, Wayne; Schrader, Sophie; Joshi, Anand; Engwer, Christian; Wolters, Carsten H.; Mosher, John C.; Leahy, Richard M. Brainstorm-DUNEuro: An integrated and user-friendly Finite Element Method for modeling electromagnetic brain activity. NeuroImage Vol. 267, 2023 online
Renelt, Lukas; Ohlberger, Mario; Engwer, Christian An optimally stable approximation of reactive transport using discrete test and infinite trial spaces. Finite Volumes for Complex Applications X—Volume 2, Hyperbolic and Related ProblemsSpringer Proceedings in Mathematics & Statistics Vol. 2, 2023 online
Erdbrügger, T.; Westhoff, A.; Höltershinken, M.; Radecke, J.-O.; Buschermöhle,Y.; Buyx, A.; Wallois, F.; Pursiainen, S.; Gross, J.; Lencer, R.; Engwer, C.; Wolters, C.H. CutFEM forward modeling for EEG source analysis. Frontiers in Human Neuroscience Vol. 17, 2023 online
Renelt, Lukas; Ohlberger, Mario; Engwer, Christian An optimally stable approximation of reactive transport using discrete test and infinite trial spaces. Finite Volumes for Complex Applications X—Volume 2, Hyperbolic and Related ProblemsSpringer Proceedings in Mathematics & Statistics Vol. 2, 2023 online
Bastian P, Blatt M, Dedner A, Dreier N, Engwer C, Fritze R, Gräser C, Kempf D, Klöfkorn R, Ohlberger M, Sander O The DUNE Framework: Basic Concepts and Recent Developments. Computers & Mathematics with Applications Vol. 81, 2021, pp 75-112 online
Streitbürger Florian, Engwer Christian, May Sandra, Nüßing Andreas Monotonicity considerations for stabilized DG cut cell schemes for the unsteady advection equation. , 2021 online
Dreier Nils-Arne, Engwer Christian Strategies for the vectorized Block Conjugate Gradients method. , 2021 online
Current ProjectsInterdisziplinäres Lehrprogramm zu maschinellem Lernen und künstlicher Intelligenz

The aim of the project is to establish and test a graduated university-wide teaching programme on machine learning (ML) and artificial intelligence (AI). AI is taught as an interdisciplinary cross-sectional topic that has diverse application possibilities in basic research as well as in economy and society, but consequently also raises social, ethical and ecological challenges.

The modular teaching program is designed to enable students to build up their AI knowledge, apply it independently and transfer it directly to various application areas. The courses take place in a broad interdisciplinary context, i.e., students from different departments take the courses together and work together on projects.

online
BrainStorm: Highly Extensible Software for Advanced Electrophysiology and MEG/EEG Imaging Software grant for integrating DUNEuro (http://www.duneuro.org) into Brainstorm (http://neuroimage.usc.edu/brainstorm) online
EXC 2044 - C1: Evolution and asymptotics In this unit, we will use generalisations of optimal transport metrics to develop gradient flow descriptions of (cross)-diffusion-reaction systems, rigorously analyse their pattern forming properties, and develop corresponding efficient numerical schemes. Related transport-type- and hyperbolic systems will be compared with respect to their pattern-forming behaviour, especially when mass is conserved. Bifurcations and the effects of noise perturbations will be explored.

Moreover, we aim to understand defect structures, their stability and their interactions. Examples are the evolution of fractures in brittle materials and of vortices in fluids. Our analysis will explore the underlying geometry of defect dynamics such as gradient descents or Hamiltonian structures. Also, we will further develop continuum mechanics and asymptotic descriptions for multiple bodies which deform, divide, move, and dynamically attach to each other in order to better describe the bio-mechanics of growing and dividing soft tissues.

Finally, we are interested in the asymptotic analysis of various random structures as the size or the dimension of the structure goes to infinity. More specifically, we shall consider random polytopes and random trees.For random polytopes we would like to compute the expected number of faces in all dimensions, the expected (intrinsic) volume, and absorption probabilities, as well as higher moments and limit distributions for these quantities. online
EXC 2044 - C2: Multi-scale phenomena and macroscopic structures In multi-scale problems, geometry and dynamics on the micro-scale influence structures on coarser scales. In this research unit we will investigate and analyse such structural interdependence based on topological, geometrical or dynamical properties of the underlying processes.

We are interested in transport-dominated processes, such as in the problem of how efficient a fluid can be stirred to enhance mixing, and in the related analytical questions. A major concern will be the role of molecular diffusion and its interplay with the stirring process. High Péclet number flow in porous media with reaction at the surface of the porous material will be studied. Here, the flowinduces pore-scale fluctuations that lead to macroscopic enhanced diffusion and reaction kinetics. We also aim at understanding advection-dominated homogenisation problems in random regimes.

We aim at classifying micro-scale geometry or topology with respect to the macroscopic behaviour of processes considered therein. Examples are meta material modelling and the analysis of processes in biological material. Motivated by network formation and fracture mechanics in random media, we will analyse the effective behaviour of curve and free-discontinuity energies with stochastic inhomogeneity. Furthermore, we are interested in adaptive algorithms that can balance the various design parameters arising in multi-scale methods. The analysis of such algorithms will be the key towards an optimal distribution of computational resources for multi-scale problems.

Finally, we will study multi-scale energy landscapes and analyse asymptotic behaviour of hierarchical patterns occurring in variational models for transportation networks and related optimal transport problems. In particular, we will treat questions of self-similarity, cost distribution, and locality of the fine-scale pattern. We will establish new multilevel stochastic approximation algorithms with the aim of numerical optimisation in high dimensions. online
EXC 2044 - C4: Geometry-based modelling, approximation, and reduction In mathematical modelling and its application to the sciences, the notion of geometry enters in multiple related but different flavours: the geometry of the underlying space (in which e.g. data may be given), the geometry of patterns (as observed in experiments or solutions of corresponding mathematical models), or the geometry of domains (on which PDEs and their approximations act). We will develop analytical and numerical tools to understand, utilise and control geometry, also touching upon dynamically changing geometries and structural connections between different mathematical concepts, such as PDE solution manifolds, analysis of pattern formation, and geometry. online
E-Mailchristian.engwer@uni-muenster.de
Phone+49 251 83-35067
FAX+49 251 83-32729
Room120.020
Secretary   Sekretariat Wernke
Frau Silvia Wernke
Telefon +49 251 83-35052
Fax +49 251 83-32729
Zimmer 120.001
AddressProf. Dr. Christian Engwer
Angewandte Mathematik Münster: Institut für Analysis und Numerik
Fachbereich Mathematik und Informatik der Universität Münster
Orléans-Ring 10
48149 Münster
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