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Oberseminar Wissenschaftliches Rechnen und Modellbildung

Profs. Bornemann/Brokate/Bungartz/Huckle/Junge

Im Wintersemester 2013/2014 fanden folgende Vorträge statt

12.02.14 14:00 Dr. Jan-Frederik Mennemann, TU Wien 02.08.011 Optimal Control of Bose Einstein Condensates

12.2.14: Optimal Control of Bose Einstein Condensates

We consider optimal control of Bose-Einstein condensates in magnetic microtraps. A Bose-Einstein condensate is a state of matter formed by bosons which are cooled to temperatures very near to absolute zero. The mean-field dynamics of a coherent Bose-Einstein condensate can be described by the nonlinear time-dependent Gross-Pitaevskii equation. The confining potential is parameterized by a single valued control parameter lambda. Our aim is to find an optimal time evolution of lambda which steers the condensate from an intitial state at time zero to a desired state at final time T. We define the objective of the control and review the optimality system. To solve the state and adjoint equations we employ a time-splitting spectral method or the classical Runge-Kutta method in combination with higher-order finite difference discretizations. Finally, we discuss different solvers for the minimum search to compute an optimal control. Up until now, this kind of quantum control problem has been considered in one spatial dimension only. In this talk we explain the problems which arise if the full three-dimensional model is considered and our strategy to solve these problems.

initial_state.jpg final_state.jpg

Im Wintersemester 2012/2013 fanden folgende Vorträge statt

| Datum |*Zeit* | Gast |*Raum* | Thema |
04.02.13 17:15 Dominic Kohler, Siemens AG/TUM 02.08.011 Cellular Probabilistic Automata - A Novel Method for Uncertainty Propagation
28.01.13 17:15 Dr. Marco Sarich, FU Berlin 02.08.011 Metastable Decompositions - About conformation dynamics and an application to modular networks
01.10.12 17:00 Prof. Miroslav Tùma, Prag 02.07.023 Preconditioning of Iterative Solvers for Linear Least-Squares Problems

04.02.13: Cellular Probabilistic Automata - A Novel Method for Uncertainty Propagation

Abstract: Development of real-time tools for uncertainty propagation is of increasing interest in industrial applications such as monitoring of infrastructure grids. However, it faces major challenges due to the complexity of the underlying models. To meet these challenges we introduce a novel density based numerical method for uncertainty propagation under certain partial differential equation dynamics. The main idea is to translate them into objects that we call cellular probabilistic automata and to evolve the latter. The translation is achieved by state discretization as in set oriented numerics and the use of the locality concept from cellular automata theory. We develop the method at the example of initial value uncertainties under deterministic dynamics and prove a consistency result. As an application we discuss arsenate transportation and adsorption in drinking water grids. For this purpose the novel method is extended to a model system of partial differential and algebraic equations, and our results are compared to Monte Carlo computations.

28.01.13: Metastable Decompositions - About conformation dynamics and an application to modular networks

Abstract: Approximately 16 years ago, the idea emerged to construct Markov chain models for reversible, time-continuous Markov processes using metastable decompositions of the state space. In the first part of the talk, we will show a functional analytic point of view, which interprets the approach as a discretization of the associated transfer operator by Galerkin projection. This will allow for an error analysis and adaptive refinement concepts for the discretization. Surprisingly, it will turn out that it is also possible to avoid such a refinement while even enhancing the approximation quality at the same time. In the second part of the talk, we will discuss how one can use this framework for the analysis of modular networks. Particularly, we will outline an algothmic strategy for efficient module identification in networks and talk about the possibilities of hierarchical soft clustering.

Im Sommersemester 2012 fanden folgende Vorträge statt

Datum Zeit Gast Raum Thema
23.7.12 17:15 Prof. Dr. Holger Wendland, Universität Bayreuth 02.08.011 Gitterfreie, kernbasierte Verfahren zur Lösung partieller Differentialgleichungen

Im Wintersemester 2011/2012 fanden folgende Vorträge statt

Datum Zeit Gast Raum Thema
5.12.11 17:15 Dr. Janosch Rieger, Goethe-Universität Frankfurt 02.08.011 Semi-implicit Euler schemes for differential inclusions
12.3.12 15:00 Prof. George Biros, University of Texas at Austin MI 02.07.023 Octree Methods in Scientific Computing
22.3.12 14:00 Prof. Bernhard Burgeth, Saarland University 02.08.011 Adaptive PDE-Based Image Processing of Matrix Fields

Im Wintersemester 2010/2011 fanden folgende Vorträge statt

Datum Zeit Gast Raum Thema
26.10.10 13:00 Prof. Matthias Bolten, Bergische Universität Wuppertal 02.07.023 Aggregation and smoothed aggregation-based multigrid methods for circulant and Toeplitz matrices
8.11.10 17:00 Dr. Yiqui Dong, Helmholtz Zentrum München 02.08.011 Multi-Scale Total Variation with Automated Regularization Parameter Selection for Image Restoration
15.11.10 17:00 Cédric M. Campos, Instituto die Ciencias Matemáticas, Madrid, Spanien 02.08.011 The ambiguity within Higher-Order Classical Field Theories
16.11.10 13:00 Marco Donatelli, Universität Como, Italien 02.07.023 Fast transforms for high order boundary conditions in image deblurring
21.12.10 13:00 Boris Khoromskij, Max-Planck Institut, Leibzig 02.07.023 Quantics-TT preconditioned and DMRG methods in high-dimensional quantum and stochastic computations
10.03.11 17:00 Christine Tobler, ETH Zürich, Schweiz 02.07.023 A Matlob Toolbox for tensors in hierarchical Tucker format and its application to the solution of high-dimensional linear systems

Im Sommersemester 2010 fanden folgende Vorträge statt

Datum Zeit Gast Raum Thema
21.6.10 17:15 Dr. Domingo Hernández-Abreu, Universidad de La Laguna (Spain) 02.08.011 On a uniparametric family of strongly A-stable Runge-Kutta collocation methods for stiff systems and DAEs

Im Wintersemester 2009/2010 fanden keine Vorträge statt

Im Sommersemester 2009 fanden folgende Vorträge statt

DatumSorted ascending Zeit Gast Raum Thema
09.07.09 16:00 entfällt! Prof. Dr. Tobias Jahnke, TH Karlsruhe 00.11.038 An adaptive wavelet method for the chemical master equation
14.09.09 17:15 Prof. Dr. Roland Freund, University of California, Davis 02.08.011 SPRIM: ein Struktur-erhaltendes Krylov-Unterraum-Verfahren zur Modellreduktion

Im Wintersemester 2008/2009 fanden folgende Vorträge im Seminarraum 02.08.011 statt

Datum Zeit Gast Thema
03.11.08 17:15 Prof. Dr. Linda Petzold, University of California, Santa Barbara Computational Methods for Phase Response Analysis of Circadian Clocks
24.11.08 17:15 Prof. Gary Froyland, University of New South Wales, Sidney Coherent sets and Perron-Frobenius cocycles
12.01.09 17:15 Dong Chen, GE Research, Garching Sparse MRI Transmit Design Using Orthogonal Matching Pursuit
09.02.09 17:15 Prof. Nicole Marheineke TU Kaiserslautern On Models and Methods for Viscous Jets

Im Sommersemester 08 fanden folgende Vorträge im Seminarraum 02.08.011 statt

Datum Zeit Gast Thema
28.4.08 17:15 Atanas Pavlov, BMW AG Model order reduction: Applications to modelling of cryogenic hydrogen tank
16.5.08 10:00 Prof. Sibel Tari, Middle East Technical University Ankara, Türkei The Edge Strength Function: Harmonic Analysis Perspective
30.6.08 17:15 Prof. Dr. Lars Grüne, Universität Bayreuth Analyse und Entwurf nichtlinearer prädiktiver Regelungsverfahren ohne Endbeschränkungen
7.7.08 17:15 Dr. Michael Metzger, Siemens AG System- und Kontrolltheorie als Schlüsseltechnologie für Design und Betriebsführung vernetzter dezentraler Energiesysteme

Im Wintersemester 07/08 haben folgende Vorträge im Seminarraum 02.08.011 stattgefunden:

Datum Zeit Gast Thema
22.10.07 17:15 Prof. Andreas Veeser, Università degli Studi di Milano, Italien A basic convergence result for adaptive finite elements
10.12.07 17:15 Dr. Dr. Fabian Theis Pfeil, GSF Umwelt und Gesundheit Algorithmic solutions to inverse problems using statistical independence
04.02.07 17:15 Prof. Dr. Gerhard Starke, Leibniz Universität Hannover Eine adaptive gemischte Finite-Element-Methode für das Signorini-Kontaktproblem