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Wednesday, 07.12.2016, 10.00 Uhr (WIAS-ESH)
Forschungsseminar Mathematische Statistik
Prof. V. Spokoiny, WIAS Berlin:
Adaptive weights clustering
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
The paper discusses a new method of unsupervised learning for high dimensional data based on the idea of adaptive weights from Polzehl and Spokoiny (2000). The procedure recovers the unknown clustering structure without any prior information about the number of clusters, their size, distance between clusters, etc. The approach extends the popular k-mean and density based clustering procedures by using dynamically updated local weights. Theoretical results describe two major features of the method: propagation within a homogeneous region and separation between two different regions. Numerical results show state-of-art performance of the new procedure.

Host
WIAS Berlin
Universität Potsdam
SFB 649: Ökonomisches Risiko
Humboldt-Universität zu Berlin
Wednesday, 07.12.2016, 15.15 Uhr (WIAS-ESH)
BERLINER OBERSEMINAR Nichtlineare partielle Differentialgleichungen (Langenbach-Seminar)
Dr. V. Laschos, WIAS Berlin:
From differential equations to gradient flows on metric spaces and back
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, 08.12.2016, 09.00 Uhr (WIAS-406)
Halbleiterseminar
Dr. D. Peschka, WIAS:
Gradient structure for optoelectronic models of semiconductor
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Further Informations
Halbleiterseminar

Host
WIAS Berlin
Thursday, 08.12.2016, 11.00 Uhr (WIAS-406)
Analysis-Stochastik-Seminar
Dr. M. Heida, WIAS Berlin:
Stochastic two-scale convergence (part I)
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Further Informations
Analysis-Stochastik-Seminar

Host
WIAS Berlin
Wednesday, 14.12.2016, 15.15 Uhr (WIAS-ESH)
BERLINER OBERSEMINAR Nichtlineare partielle Differentialgleichungen (Langenbach-Seminar)
Dr. G. Kitavtsev, University of Bristol, GB:
Liquid crystal defects in the Landau-de Gennes theory in 2D-beyond the one-constant approximation
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
here

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

Host
WIAS Berlin
Humboldt-Universität zu Berlin
Thursday, 15.12.2016, 09.00 Uhr (WIAS-406)
Halbleiterseminar
Dr. M. Liero, WIAS:
Electro-thermal effects in organic semiconductors
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)

Further Informations
Halbleiterseminar

Host
WIAS Berlin
Monday, 19.12.2016, 14.00 Uhr (WIAS-ESH)
INSTITUTSKOLLOQUIUM
Dr. B. Zwicknagl, Universität Bonn, Germany:
Variational analysis of microstructures in low-hysteresis shape memory alloys
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
The formation of patterns in solids is often explained as the result of a competition between an elastic bulk energy and a higher order surface energy. As an example we will discuss microstructures in shape memory alloys, which are usually modeled by singularly perturbed non-convex bulk energies. The main focus will be on recent analytical results for shape memory alloys which have been found experimentally to have particularly low hysteresis.

Host
WIAS Berlin
Tuesday, 20.12.2016, 14.00 Uhr (WIAS-ESH)
INSTITUTSKOLLOQUIUM
Dr. M.-Th. Wolfram, University of Warwick, Mathematics Institute / Johann Radon Institute Linz (RICAM), Austria:
Applied PDE in the socio-economic sciences
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
In recent years nonlinear PDE models have been used successfully in various applications in socio-economic sciences. For example to describe opinion for- mation and knowledge growth in a society, or the collective dynamics of large pedestrian crowds.
In this talk we focus on two PDE models for socio-economic problems. First a Boltzmann mean- eld game approach to describe knowledge and economic growth in a society; and second a nonlinear PDE model for interacting pedes- trian ows. We start by discussing the underlying microscopic modelling as- sumptions as well as the corresponding mean- eld equations. Then we focus on the existence and linear stability of solutions in either case. Finally we construct special solutions, which relate to sustained economic growth or segregation of flows, and illustrate the dynamics of both models with numerical simulations.

Host
WIAS Berlin
Tuesday, 10.01.2017, 10.00 Uhr (WIAS-ESH)
Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations / Mathematical Optimization
Dr. K. F. Lam, Universität Regensburg:
Diffuse interface models of tumor growth and optimizing cancer treatment times
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
There has been a recent focus in modeling tumor growth with diffuse interface models, due to their ability to capture topological transitions and the nature of the equations allows for further mathematical treatment. In the first part of this talk I will introduce a class of Cahn-Hilliard systems that are used to capture the basic dynamics of tumor growth. Then, we will discuss an optimal control problem for chemotherapy, which is a cancer treatment using drugs to eliminate tumor cells. Treatments are usually conducted in cycles, and long treatment times may cause harm to the patient. Thus, it is important to optimize both the treatment time and drug dosage to minimize patient suffering. In the second part of this talk, we will analyze an optimal control problem with an objective functional depending on a free time variable, which represents the unknown treatment time to be optimized.

Further Informations
Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations / Mathematical Optimization

Host
WIAS Berlin
Tuesday, 31.01.2017, 10.15 Uhr (WIAS-ESH)
Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations / Mathematical Optimization
Dr. S. Merino-Aceituno, Imperial College London, GB:
Kinetic theory to study emergent phenomena in biology: An example on swarming
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal

Abstract
Classical methods in kinetic theory are challenged when studying emergent phenomena in the biological and social sciences. New methodologies are needed to study the problems at hand which typically involve many agents that interact locally. The aim of this talk is to introduce the general framework of kinetic theory and some of the new challenges of applying it to biological systems. We illustrate it in the case of the so-called collective motion of self-propelled particles, like swarming of birds. Particularly, based on the Vicsek model, we study systems of agents (birds) that move at a constant speed while trying to align their body orientation with those of their neighbours. Starting from a particle description, we find the macroscopic dynamics.

Further Informations
Joint Research Seminar on Nonsmooth Variational Problems and Operator Equations / Mathematical Optimization

Host
WIAS Berlin