Upcoming Events

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Tuesday, 22.10.2019, 15:00 (WIAS-405-406)
Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Dr. Oleg Butkovsky, WIAS Berlin:
Regularization by noise for SDEs and SPDEs with applications to numerical methods
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406

Host
WIAS Berlin
Wednesday, 23.10.2019, 10:00 (WIAS-ESH)
Forschungsseminar Mathematische Statistik
Prof. Vladimir Spokoiny, WIAS Berlin, HU Berlin:
Bayesian inference for nonlinear inverse problems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
We discuss the properties of the posterior for a wide class of statistical models including nonlinear generalised regression and deep neuronal networks, nonlinear inverse problems, nonparametric diffusion, error-in-operator and IV models. The new calming approach helps to treat all such problems in a unified manner and to obtain tight finite sample results about Gaussian approximation of the posterior with an explicit error bound in term of so called effective dimension.

Host
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
Wednesday, 23.10.2019, 11:00 (WIAS-HVP-3.13)
Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations / Mathematical Optimization
Dr. Martin Holler, Universität Graz, Österreich:
A variational model for learning convolutional image atoms from incomplete data
more ... Location
Weierstraß-Institut, Hausvogteiplatz 11A, 10117 Berlin, 3. Etage, Raum: 3.13

Abstract
Using lifting and relaxation strategies, we present a convex variational model for learning a convolutional sparse representation of image data via a few basic atoms. Such a representation provides a model for repeating patterns, but is also of interest for classification or as structural prior. We ensure well-posedness results for the proposed model in a general inverse problems setting and provide numerical experiments, where an atom-based representation is computed from incomplete, noisy and blurry data.

Further Informations
Joint Research Seminar on Mathematical Optimization / Non-smooth Variational Problems and Operator Equations

Host
Humboldt-Universität zu Berlin
WIAS Berlin
Wednesday, 23.10.2019, 14:00 (WIAS-ESH)
Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Prof. Dr. Ansgar Jüngel, Technische Universität Wien, Österreich:
Cross-diffusion systems: from spin semiconductors to biological populations with stochastic forcing
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Many real-world applications consist of multiple components, leading on the macroscopic scale to cross-diffusion systems which consist of strongly coupled parabolic equations. The applications may be very diverse and range from spin-polarized transport in semiconductors and ion transport in cell membranes to population dynamics. In this talk, some existence results for global-in-time weak solutions is proved, based on entropy methods. This technique was already used by Herbert Gajewski, and we detail some of his ideas to prove the large-time behavior and uniqueness of weak solutions, followed by some extensions like boundedness-by-entropy and martingale solutions to stochastic cross-diffusion systems.

Host
Humboldt-Universität zu Berlin
WIAS Berlin