Events & Teaching

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January 27 – 29, 2015 (WIAS-ESH)
Workshop/Konferenz: 3rd Annual ERC Berlin-Oxford Young Researchers Meeting on Applied Stochastic Analysis
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Host
WIAS Berlin
European Research Council
Tuesday, 27.01.2015, 10.15 Uhr (WIAS-406)
Seminar Nichtlineare Optimierung und Inverse Probleme
H. Meinlschmidt, Technische Universität Darmstadt:
Optimalsteuerung des 3D Thermistor-Problems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Host
WIAS Berlin
Tuesday, 27.01.2015, 15.15 Uhr (WIAS-HVP-4.13)
Oberseminar Nonlinear Dynamics
Prof. A. Azouani, Mohamed Premier University, Morocco:
Feedback control of nonlinear dissipative dynamical systems using general interpolant observables and continuous data assimilation
more ... Location
Weierstraß-Institut, Hausvogteiplatz 11A, 10117 Berlin, 4. Etage, Raum: 4.13

Abstract
In this work we propose a new feedback control for controlling general dissipative evolution equations using any of the determining systems of parameters (modes, nodes, volume elements, etc...) without requiring the presence of separation in spatial scales, i.e. without assuming the existence of an inertial manifold. For more reaching applications, we present a continuous data assimilation algorithm based on our feedback control ideas in the context of the incompressible two-dimensional Navier-Stokes equations.

Further Informations
Oberseminar Nonlinear Dynamics

Host
WIAS Berlin
Freie Universität Berlin
Wednesday, 28.01.2015, 10.00 Uhr (WIAS-HVP-4.13)
Forschungsseminar Mathematische Statistik
Prof. M. Haltmeier, Universität Innsbruck, Österreich:
Extreme value analysis of frame coefficients and applications
more ... Location
Weierstraß-Institut, Hausvogteiplatz 11A, 10117 Berlin, 4. Etage, Raum: 4.13

Abstract
Consider the problem of estimating a high-dimensional vector from linear observations that are corrupted by additive Gaussian white noise. Many solution approaches for such problems construct an estimate as the most regular element satisfying a bound on the coefficients of the residuals with respect to some frame. In order that the true parameter is feasible, the coefficients of the noise must satisfy the bound. For that purpose we compute the asymptotic distribution of these coefficients. We show that generically a standard Gumbel law results, as it is known from the case of orthonormal bases. However, for highly redundant frames other limiting laws may occur. We discuss applications of such results for thresholding in redundant wavelet or curvelet frames, and for the Dantzig selector.

Host
WIAS Berlin
Humboldt-Universität zu Berlin
Universität Potsdam
Thursday, 29.01.2015, 16.15 Uhr (WIAS-405-406)
Forschungsseminar Mathematische Modelle der Photonik
M. Kantner, WIAS Berlin:
Numerical simulation of an electrically pumped single-photon emitter
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406

Host
Humboldt-Universität zu Berlin
WIAS Berlin
Wednesday, 04.02.2015, 15.15 Uhr (WIAS-ESH)
BERLINER OBERSEMINAR Nichtlineare partielle Differentialgleichungen (Langenbach-Seminar)
Prof. Dr. J. Sprekels, WIAS Berlin:
Optimal boundary control problems for Cahn-Hilliard systems with singular potentials and dynamic boundary conditions
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

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

Host
WIAS Berlin
Humboldt-Universität zu Berlin
Thursday, 05.02.2015, 16.00 Uhr (WIAS-ESH)
Forschungsseminar Mathematische Modelle der Photonik
Dr. A. Pimenov, WIAS Berlin:
Dynamics of passively mode-locked inhomogeneously broadened lasers
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Host
Humboldt-Universität zu Berlin
WIAS Berlin
Tuesday, 10.02.2015, 12.30 Uhr (WIAS-406)
Seminar Thermodynamische Modellierung und Analyse von Phasenübergängen
Prof. E. Spohr, Universität Duisburg-Essen:
MD Simulations of structure and reaction dynamics at the liquid / solid electrode interface
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Host
WIAS Berlin
Tuesday, 10.02.2015, 13.30 Uhr (WIAS-ESH)
Seminar Numerische Mathematik
Prof. R. Masson, Université de Nice Sophia Antipolis, France:
Gradient scheme discretizations of two phase porous media flows in fractured porous media
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
This talk presents the gradient scheme framework for the discretization of two-phase Darcy flows in discrete fracture networks taking into account the mass exchange between the matrix and the fracture. We consider the asymptotic model for which the fractures are represented as interfaces of codimension one immersed in the matrix domain, leading to the so called hybrid dimensional Darcy flow model. The pressures at the interfaces between the matrix and the fracture network are continuous corresponding to a ratio between the normal permeability of the fracture and the width of the fracture assumed to be large compared with the ratio between the permeability of the matrix and the size of the domain. Two type of discretizations matching the gradient scheme framework are discussed including the extensions of the Hybrid Finite Volume (HFV) and of the Vertex Approximate Gradient (VAG) schemes to the case of hybrid dimensional Darcy flow models. Compared with Control Volume Finite Element (CVFE) approaches, the VAG scheme has the advantage to avoid the mixing of the fracture and matrix rock types at the interfaces between the matrix and the fractures, while keeping the low cost of a nodal discretization on unstructured meshes. The convergence of the gradient schemes is obtained for two phase flow models under the assumption that the relative permeabilities are bounded from below by a strictly positive constant. This assumption is needed in the convergence proof only in order to take into account discontinuous capillary pressures in particular at the matrix fracture interfaces. The efficiency of our approach is shown on numerical examples of fracture networks in 2D and 3D.

Host
WIAS Berlin
Wednesday, 11.02.2015, 10.00 Uhr (WIAS-405-406)
Seminar Materialmodellierung
K. Schade, TU Darmstadt:
Dynamics of nematic liquid crystal flows: The quaslinear approach
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406

Abstract
Liquid crystals are matter in a state between liquid and solid. They flow like a liquid, but their molecular structure is similar to that of a solid crystal. In the most common nematic phase, molecules possess an orientation but no positional order. The Ericksen-Leslie model describes the flow of nematic liquid crystals with Navier-Stokes equations coupled with a diffusion equation governing the behavior of the direction field.
 
We analyze some Ericksen Leslie systems in a quasilinear setting. We show the local existence of strong solutions using a variant of Clément-Li together with maximal Lp-regularity results. We also investigate stability of equilibria with the generalized principle of linearized stability, obtain global existence of strong solutions which are eventually bounded on their maximal existence interval and discuss regularizing effects.

Further Informations
WIAS-Materialmodellierungsseminar

Host
WIAS Berlin
Wednesday, 11.02.2015, 15.15 Uhr (WIAS-ESH)
BERLINER OBERSEMINAR Nichtlineare partielle Differentialgleichungen (Langenbach-Seminar)
M. Egert, TU Darmstadt:
On Kato's square root problem
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

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

Host
WIAS Berlin
Humboldt-Universität zu Berlin
Thursday, 12.02.2015, 16.15 Uhr (WIAS-405-406)
Forschungsseminar Mathematische Modelle der Photonik
S. Lange, Heinrich Hertz Institut Berlin:
Optical feedback effects in monolithically integrated laser-Mach-Zehnder modulator transmitter PICs
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406

Host
Humboldt-Universität zu Berlin
WIAS Berlin
February 13, 2015 (WIAS-ESH)
Workshop/Konferenz: Dynamics and Stability of Interacting Nonlinear Oscillators and their Applications
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Host
WIAS Berlin
Potsdam-Institut für Klimafolgenforschung
March 11 – 13, 2015 (WIAS-ESH)
Workshop/Konferenz: Applied Mathematics and Simulation for Semiconductors
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Host
WIAS Berlin
February 22 – 26, 2016 (WIAS-ESH)
Workshop/Konferenz: ERC Workshop "Modeling Materials and Fluids using Variational Methods''
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Host
WIAS Berlin