39 research outputs found
Adaptive synchronization in delay-coupled networks of Stuart-Landau oscillators
We consider networks of delay-coupled Stuart-Landau oscillators. In these
systems, the coupling phase has been found to be a crucial control parameter.
By proper choice of this parameter one can switch between different synchronous
oscillatory states of the network. Applying the speed-gradient method, we
derive an adaptive algorithm for an automatic adjustment of the coupling phase
such that a desired state can be selected from an otherwise multistable regime.
We propose goal functions based on both the difference of the oscillators and a
generalized order parameter and demonstrate that the speed-gradient method
allows one to find appropriate coupling phases with which different states of
synchronization, e.g., in-phase oscillation, splay or various cluster states,
can be selected.Comment: 8 pages, 7 figure
Controlled Synchronization Under Information Constraints
The class of controlled synchronization systems under information constraints
imposed by limited information capacity of the coupling channel is analyzed. It
is shown that the framework proposed in A. L. Fradkov, B. Andrievsky, R. J.
Evans, Physical Review E 73, 066209 (2006) is suitable not only for
observer-based synchronization but also for controlled master-slave
synchronization via communication channel with limited information capacity. A
simple first order coder-decoder scheme is proposed and a theoretical analysis
for multi-dimensional master-slave systems represented in the Lurie form
(linear part plus nonlinearity depending only on measurable outputs) is
provided. An output feedback control law is proposed based on the Passification
theorem. It is shown that the upper bound of the limit synchronization error is
proportional to the upper bound of the transmission error. As a consequence,
both upper and lower bounds of limit synchronization error are proportional to
the maximum rate of the coupling signal and inversely proportional to the
information transmission rate (channel capacity). The results are applied to
controlled synchronization of two chaotic Chua systems coupled via a controller
and a channel with limited capacity.Comment: 7 pages, 8 figure
Oscillatority Conditions for Nonlinear Systems with Delay
Sufficient conditions for oscillatority in the sense of Yakubovich for
a class of time delay nonlinear systems are proposed. Under proposed conditions,
upper and lower bounds for oscillation amplitude are given. Examples illustrating
analytical results by computer simulation are presented
Complex partial synchronization patterns in networks of delay-coupled neurons
We study the spatio-temporal dynamics of a multiplex network of delay-coupled FitzHugh–Nagumo oscillators with non-local and fractal connectivities. Apart from chimera states, a new regime of coexistence of slow and fast oscillations is found. An analytical explanation for the emergence of such coexisting partial synchronization patterns is given. Furthermore, we propose a control scheme for the number of fast and slow neurons in each layer.DFG, 163436311, SFB 910: Kontrolle selbstorganisierender nichtlinearer Systeme: Theoretische Methoden und Anwendungskonzept