Kolloquiumsvortrag, Dr. Philip Hövel, Inst. f. Theoretische Physik, TU Berlin, / am 30.01.2017

30.01.2016 von 17:15 bis 18:45

Technische Fakultät, Institut für Elektrontechnik und Informationstechnik, Kaiserstr. 2, Kiel, Raum: "Aquarium", Geb. D

Titel: Control of cluster synchronization in delay-coupled oscillators by network adaptation

Abstract:

Adaptive networks are characterized by mutual interactions between the dynamics of the nodes on one hand and a co-evolution of the coupling topology on the other hand: The topology evolves according to the state of the system, while at the same time the dynamics on the network is influenced by that changing topology.

In my presentation, I will discuss an adaptive control scheme for the control of in-phase and cluster synchronization in delay-coupled networks of "Stuart-Landau oscillators". This paradigmatic normal form arises naturally in an expansion of systems close to a Hopf bifurcation. Based on an automated control scheme called "speed-gradient method", the topology of a network adjusts itself in a self-organized manner such that the target state is realized. I will provide numerical evidence that the networked system settles into different cluster states depending on the pre-defined control function.

Furthermore, I will demonstrate that the emerging topology of the network is modulated by the coupling delay. If the delay time is a multiple of the system's eigenperiod, the coupling within a cluster and to neighboring clusters is on average positive (excitatory), while the coupling to clusters with a phase lag close to pi is negative (inhibitory). For delay times equal to odd multiples of half of the eigenperiod, the opposite holds: Nodes within one cluster and of neighboring clusters are coupled by inhibitory links, while the coupling to clusters distant in phase state is excitatory. In addition, the control scheme is able to construct networks such that they exhibit not only a given cluster state but also oscillate with a prescribed frequency. Finally, I will illustrate the effectiveness of the speed-gradient method in cases, where only part of the network is accessible.

References:

J. Lehnert, Controlling synchronization patterns in complex networks, Springer Theses, Springer, (2016).


J. Lehnert, P. Hövel, A. A. Selivanov, A. L. Fradkov, and E. Schöll: Controlling cluster synchronization by adapting the topology Phys. Rev. E 90, 042914 (2014).

E. Schöll, A. A. Selivanov, J. Lehnert, T. Dahms, P. Hövel, and A. L. Fradkov: Control of
synchronization in delay-coupled networks, Int. J. Mod. Phys. B 26, 1246007 (2012).

A. A. Selivanov, J. Lehnert, T. Dahms, P. Hövel, A. L. Fradkov, and E. Schöll: Adaptive synchronization for delay-coupled networks of Stuart-Landau oscillators, Phys. Rev. E 85, 016201 (2012).

J. Lehnert, P. Hövel, V. Flunkert, P. Y. Guzenko, A. L. Fradkov, and E. Schöll: Adaptive tuning of feedback gain in time-delayed feedback control, Chaos 21, 043111 (2011).

-- Dr. Philipp Hövel Junior Research Group Leader

Prof. Hermann Kohlstedt

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