Veranstaltungen

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Donnerstag, 29.06.2017, 16.00 Uhr (WIAS-ESH)
Forschungsseminar Mathematische Modelle der Photonik
Dr. A. Pimenov, WIAS Berlin:
Efficient simulation and analysis of multi-mode laser dynamics using time-delay models
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Veranstalter
WIAS Berlin
Dienstag, 04.07.2017, 15.00 Uhr (WIAS-406)
Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Dr. L. Ruthotto, Emory University, Atlanta, USA:
Stable architectures for deep neural networks
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Veranstalter
WIAS Berlin
Dienstag, 04.07.2017, 15.15 Uhr (WIAS-ESH)
Oberseminar Nonlinear Dynamics
A. Visintin, Università di Trento, Italy:
Compactness and structural stability of nonlinear flows
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Veranstalter
Freie Universität Berlin
WIAS Berlin
Mittwoch, 05.07.2017, 18.15 Uhr (TUB-MA 041)
Berliner Kolloquium Wahrscheinlichkeitstheorie/Berlin Young Probabilists' Seminar
Prof. Dr. I. Goldsheid, Queen Mary, University of London, GB:
Invariant Measure for Random Walks on Random Environments
mehr ... Veranstaltungsort
Technische Universität, Straße des 17. Juni 136, 10623 Berlin, MA 041

Abstrakt
It is well known that a random walk in random environment on a strip in the "environment viewed from the particle" setting is a Markov chain on the set of environments. In this context, the fundamental question is that of the existence of the density of the invariant measure of this Markov chain with respect to the measure on the set of environments. In the case of the walk on a strip, it turns out to be possible to describe all positive sub-exponentially growing solutions of the corresponding invariant measure equation in the deterministic setting and then derive the necessary and sufficient conditions for the existence of the density when the environment is stationary and ergodic. This is a joint work with D. Dolgopyat.

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Berliner Kolloquium Wahrscheinlichkeitstheorie

Veranstalter
Humboldt-Universität zu Berlin
Technische Universität Berlin
Universität Potsdam
WIAS Berlin
Dienstag, 11.07.2017, 10.00 Uhr (WIAS-406)
Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Ch. Ben Hammouda, King Abdullah University of Science and Technology - KAUST, Saudi-Arabien, Königreich:
Multilevel hybrid split-step implicit tau-leap
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Abstrakt
In biochemically reactive systems with small copy numbers of one or more reactant molecules, the dynamics is dominated by stochastic effects. To approximate those systems, discrete state-space and stochastic simulation approaches have been shown to be more relevant than continuous state-space and deterministic ones. In systems characterized by having simultaneously fast and slow timescales, existing discrete space-state stochastic path simulation methods, such as the stochastic simulation algorithm (SSA) and the explicit tau-leap (explicit-TL) method, can be very slow. Implicit approximations have been developed to improve numerical stability and provide efficient simulation algorithms for those systems. Tn this talk, we propose an efficient Multilevel Monte Carlo (MLMC) method in the spirit of the work by Anderson and Higham (SIAM Multiscal Model. Simul. 10(1), 2012). This method uses split-step implicit tau-leap (SSI-TL) at levels where the explicit-TL method is not applicable due to numerical stability issues. We present numerical examples that illustrate the performance of the proposed method.

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Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics

Veranstalter
WIAS Berlin
Mittwoch, 12.07.2017, 10.00 Uhr (WIAS-ESH)
Forschungsseminar Mathematische Statistik
Prof. W. Polonik, University of California at Davis, USA:
Statistical topological data analysis: Rescaling the persistence diagram
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstrakt
A persistence diagram (PD) is one of the basic objects underlying topological data analysis. It is used to analyze topological and geometric features of an underlying space M, assuming availability of a random sample from M. Existing approaches for such analyses will be reviewed brie y, and their bene ts and shortcomings will be discussed. Then we introduce ideas for rescaling PDs, which enables the derivation of novel limit theorems for the total k persistence, and other functionals of PDs. The long-term goal of studying the rescaling of PDs is to develop novel types of statistical analysis of persistence diagrams.

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Forschungsseminar ``Mathematische Statistik''

Veranstalter
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
Mittwoch, 12.07.2017, 15.15 Uhr (WIAS-ESH)
Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar) & Seminar Materialmodellierung
Prof. Dr. R. Toader, University of Udine, Italy:
Existence for dynamic Griffith fracture with a weak maximal dissipation condition
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstrakt
The study of dynamic fracture is based on the dynamic energy-dissipation balance. This condition is always satisfied by a stationary crack together with a displacement satisfying the system of elastodynamics. Therefore to predict crack growth a further principle is needed. We introduce a weak maximal dissipation condition that, together with elastodynamics and energy balance, provides a model for dynamic fracture, at least within a certain class of possible crack evolutions. In particular, we prove the existence of dynamic fracture evolutions satisfying this condition, subject to smoothness constraints, and exhibit an explicit example to show that maximal dissipation can indeed rule out stationary cracks. These results are obtained in collaboration with G. Dal Maso (SISSA) and C. Larsen (WPI).

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Berliner Oberseminar ``Nichtlineare Partielle Differentialgleichungen'' (Langenbach Seminar) & Seminar Materialmodellierung

Veranstalter
WIAS Berlin
Humboldt-Universität zu Berlin
Mittwoch, 26.07.2017, 15.15 Uhr (WIAS-ESH)
Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
P. Gussmann, WIAS Berlin:
From finite to linear material models with self-contact
mehr ... Veranstaltungsort
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

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Berliner Oberseminar ``Nichtlineare Partielle Differentialgleichungen'' (Langenbach Seminar)

Veranstalter
WIAS Berlin
Humboldt-Universität zu Berlin