Veranstaltungen
- Donnerstag, 15.01.2026, 14:00 Uhr (WIAS-405-406)
- Seminar Numerische Mathematik
Prof. Petr Knobloch, Charles University, Tschechische Republik:
Computation of stabilization parameters using machine learning
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstrakt
For various types of partial differential equations, standard finite element discretizations are often unstable, which can be cured by adding suitable stabilization terms. Typically, these terms contain user-chosen parameters whose optimal choice is usually not known but which considerably influence the quality of the approximate solution. In this talk, we will consider stabilized methods for steady convection-diffusion equations. A typical example is the streamline upwind Petrov-Galerkin (SUPG) method. It is possible to compute the stabilization parameters a posteriori in an adaptive way by minimizing a target functional characterizing the quality of the approximate solution, however, this functional is often difficult to design. Moreover, the solution of this high-dimensional constrained nonlinear optimization problem is usually very time-consuming. Therefore, we proposed a method based on techniques from machine learning in order to select (nearly) optimal stabilization parameters in a cheap way. The idea is to compute these parameters locally based on properties of the SUPG solution obtained with standard (nonoptimal) parameters. The training phase will use parameters computed by the mentioned minimization approach employing accurate approximate solutions which can be obtained using nonlinear (and hence again costly) approaches. We will report our first experiences with this strategy. This is the joint work with Manoj Prakash (Charles University, Prague).
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Seminar Numerical Mathematics
Veranstalter
WIAS Berlin
- Dienstag, 20.01.2026, 10:15 Uhr (WIAS-406)
- Seminar Nichtlineare Optimierung und Inverse Probleme
Max Weiner, TU Bergakademie Freiberg:
A holistic view on modeling of rolling processes and attempts to its numerical solution
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Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Veranstalter
WIAS Berlin
- Mittwoch, 21.01.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Yannic Steenbeck, TU Braunschweig:
tba
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
tba
Weitere Informationen
Seminar Interactin Random Systems
Veranstalter
WIAS Berlin
- Mittwoch, 21.01.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
PD Dr. Olaf Klein, WIAS Berlin:
Uncertainty quantification for a model for a magnetostrictive material involving a hysteresis operator
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Dienstag, 27.01.2026, 15:00 Uhr (WIAS-405-406)
- Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Dr. Oleg Butkovsky, WIAS Berlin:
Pathwise uniqueness for SDEs in Hilbert spaces
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Weitere Informationen
Dieser Vortrag findet auch via Zoom statt: https://wias-berlin-de.zoom-x.de/j/69982487566
Veranstalter
WIAS Berlin
- Mittwoch, 28.01.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Anastasija Pešić, WIAS Berlin:
Curvature-driven pattern formation in biomembranes: A gradient flow approach
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- Donnerstag, 05.02.2026, 10:00 Uhr (WIAS-HVP-3.04)
- Forschungsseminar Mathematische Modelle der Photonik
Dr. Eduard Kuhn, WIAS Berlin:
Simulation of high power diode lasers with stacked multiple active regions and tunnel junctions
mehr ... Veranstaltungsort
Weierstraß-Institut, Hausvogteiplatz 11A, 10117 Berlin, 3. Etage, Raum: 3.04
Abstrakt
Many applications require diode lasers that are able to generate high output powers, for example in LiDAR (Light Detection and Ranging) systems or in future inertial confinement fusion power plants. In order to achieve high powers while maintaining low injected current densities, it is beneficial to stack multiple active regions and separate them using tunnel junctions. As the tunnel junctions are highly absorbing due to the small band gap and high doping levels, their accurate positioning in the nodes of the vertical mode is crucial. In order to answer important design questions such as the optimal distance between active regions and the tunnel junctions, a simulation tool is required. For our tool we solve the standard drift-diffusion equations augmented with additional models to describe effects such as tunneling and stimulated emission. Since the tunnel junctions are operated under reverse bias, we employ a non-local band-to-band tunneling model. This talk presents the simulation model and demonstrates its application to a multi-junction laser diode.
Weitere Informationen
Forschungsseminar Mathematische Modelle der Photonik
Veranstalter
WIAS Berlin
- Mittwoch, 11.02.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Elias Zimmermann, Universität Leipzig:
tba
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Weitere Informationen
Seminar Interacting Random Systems
Veranstalter
WIAS Berlin
- Mittwoch, 11.02.2026, 11:30 Uhr (WIAS-406)
- Seminar Interacting Random Systems
Elias Zimmermann, Universität Leipzig:
tba
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstrakt
tba
Weitere Informationen
Seminar Interactin Random Systems
Veranstalter
WIAS Berlin
- Mittwoch, 11.02.2026, 14:15 Uhr (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Andrea Poiatti, Universität Wien, Österreich:
A Navier--Stokes/Mullins--Sekerka system with different densities: Weak solutions
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstrakt
In this talk, I would like to introduce a model for the flow of two incompressible, viscous and immiscible fluids in a bounded domain, with different densities and viscosities. This model consists of a coupled system of Navier--Stokes and Mullins--Sekerka type parts, and can be obtained from the asymptotic limit of the diffuse interface model introduced by Abels, Garcke, and Grün in 2012. I will introduce a new notion of weak solutions and prove its global in time existence, together with a consistency result. This new notion of solution allows to include the case of different densities of the fluids, a sharp energy dissipation principle `a la De Giorgi, as well as a weak formulation of the constant contact angle condition at the boundary, which were left open in the previous notion of solution proposed by H. Abels and M. Röger in 2009. This is a joint project with H. Abels.
Weitere Informationen
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
- 12. – 13. Februar 2026 (WIAS-ESH)
- Workshop/Konferenz: Widening the Scope of Rough and Stochastic Analysis -- Rough Women Reach Out!
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
Technische Universität Berlin
WIAS Berlin
- 2. – 4. März 2026 (IHP)
- Workshop/Konferenz: Leibniz MMS Days 2026
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Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
Veranstalter
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
WIAS Berlin
- 1. – 5. Juni 2026 (WIAS-ESH)
- Workshop/Konferenz: ESGI 194 - The Berlin Study Group with Industry
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin
- 6. – 8. Juli 2026 (WIAS-ESH)
- Workshop/Konferenz: Spreading Dynamics in Random Environment
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Veranstalter
WIAS Berlin