Nonlinear Dynamics at the Free University Berlin

Winter 2018/2019

Seminar Advanced Topics in Nonlinear Dynamics

Prof. Dr. Bernold Fiedler, Dr. Isabelle Schneider


Program

Thursday, October 25, 2018 Hannes Stuke (FU Berlin) A dynamical systems approach to outlier robust machine learning
We deal with a supervised learning in which we want to fit probability distributions of observed data by artificial neural networks. We introduce the so-called gradient conjugate prior (GCP) update and the induced dynamical system. We will explain the dynamics of the parameters and show how one can use insights from the dynamical behavior to recover the ground truth distribution in a way that is more robust against outliers. This is joint work with Pavel Gurevich.
Thursday, November 1st, 2018
Nicola Vassena (FU Berlin) A report from outside world - are we on a shared path or on a lonely path?
Thursday, November 8th, 2018 Si Mohamed Sah (Technical University of Denmark) Infinite limit cycle bifurcation in a delayed differential equation
We investigate the occurrence of a bifurcation, which we term the ``infinite limit cycle bifurcation", or ILCB for short, in a second order nonlinear DDE (delay-differential equation). When the delay time T>0, no matter how small, an infinite number of limit cycles (LCs) exist, their amplitude going to infinity as T goes to zero. Perturbation methods are used to approximate the system and investigate the nature of such a bifurcation.
Thursday, November 15th, 2018 Maximilian Bee and Hauke Sprink (FU Berlin) The ζ-function
Nicola Vassena (FU Berlin) A divulgative talk on chemical reaction networks
Thursday, November 22nd , 2018 Nicola Vassena Bad Children and Good Children
This talk can be regarded as a linear algebra one. It is focused on characterization of determinant value for a specific class of matrices. However, this result has strong repercussion in chemical reaction networks, and specifically on the identification of "bad" child selections, possibly responsible for sign changes in the Jacobian of the system and consequent dynamical implications.
Thursday, November 29th , 2018 Ignacio González Betegon (Freie Universität Berlin) Exploring genericity results in inverse problems on coupled cell networks
In a system of ODE's, inverse problems guarantee some behaviour in the hole system by just studying one of the equations. In this talk we will introduce some symmetry condition to our system of ODE's and we will see how genericity results on inverse problems behave.
Nicola Vassena (FU Berlin) Bad children and good children
For last 30 minutes, I will make some concluding remarks regarding the bipartite graph analysis of my last week's talk.
Thursday, December 6th , 2018 Nicola Vassena (Freie Universität Berlin) Bad children and good children
Duro a morire, in the first 30 minutes, I will make some concluding remarks regarding the bipartite graph analysis of my talk from two weeks ago.
Alejandro López Nieto (Freie Universität Berlin) The Chafee-Infante attractor in delay equations
In the talk I will present a series of techniques for the study of the global attractor of a delay differential equation. The main tool is a zero dropping lemma for a class of cyclic monotone feedback systems that endows the studied equation with a Poincaré-Bendixson property, this will allow us to build a (still small) basis for the systematic construction of global attractors. The talk is rather self-contained, no specific understanding of delay equations is required.
Thursday, December 13th Alejandro López Nieto The Chafee-Infante attractor in delay equations
In the talk I will present a series of techniques for the study of the global attractor of a delay differential equation. The main tool is a zero dropping lemma for a class of cyclic monotone feedback systems that endows the studied equation with a Poincaré-Bendixson property, this will allow us to build a (still small) basis for the systematic construction of global attractors. The talk is rather self-contained, no specific understanding of delay equations is required.
Thursday, January 10th Babette de Wolff (Freie Universität Berlin) Nonlinear control for planar systems with rotational symmetry
In this talk, we study time delayed feedback control for planar systems with rotational symmetry. Whereas in the classical Pyragas control scheme the control term is chosen to be linear, we now also allow for nonlinear control terms. We discuss different classes of noninvasiveness of the control scheme and study how these can help us to overcome obstructions to the success of the control scheme.
Thursday, January 17th Isabelle Schneider (Freie Universität Berlin) An introduction to state-dependent delay equations

Time and Place

Talks usually take place on Thursday at 2:15 p.m.
at the Free University Berlin
Room 130, Arnimallee 7 (rear building), 14195 Berlin.

Guests are always welcome!


Archive

switch Last change: Jan. 17, 2019
This page strictly conforms to the XHTMLswitch1.0 standard and uses style sheets. Valid XHTML 1.0! Valid CSS!