76,298 research outputs found
Controlling chaos in spatially extended beam-plasma system by the continuous delayed feedback
In present paper we discuss the control of complex spatio-temporal dynamics
in a {spatially extended} non-linear system (fluid model of Pierce diode) based
on the concepts of controlling chaos in the systems with few degrees of
freedom. A presented method is connected with stabilization of unstable
homogeneous equilibrium state and the unstable spatio-temporal periodical
states analogous to unstable periodic orbits of chaotic dynamics of the systems
with few degrees of freedom. We show that this method is effective and allows
to achieve desired regular dynamics chosen from a number of possible in the
considered system.Comment: 12 pages, 12 figure
Investigation of the complex dynamics and regime control in Pierce diode with the delay feedback
In this paper the dynamics of Pierce diode with overcritical current under
the influence of delay feedback is investigated. The system without feedback
demonstrates complex behaviour including chaotic regimes. The possibility of
oscillation regime control depending on the delay feedback parameter values is
shown. Also the paper describes construction of a finite-dimensional model of
electron beam behaviour, which is based on the Galerkin approximation by linear
modes expansion. The dynamics of the model is close to the one given by the
distributed model.Comment: 18 pages, 6 figures, published in Int. J. Electronics. 91, 1 (2004)
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Controlling Fast Chaos in Delay Dynamical Systems
We introduce a novel approach for controlling fast chaos in time-delay
dynamical systems and use it to control a chaotic photonic device with a
characteristic time scale of ~12 ns. Our approach is a prescription for how to
implement existing chaos control algorithms in a way that exploits the system's
inherent time-delay and allows control even in the presence of substantial
control-loop latency (the finite time it takes signals to propagate through the
components in the controller). This research paves the way for applications
exploiting fast control of chaos, such as chaos-based communication schemes and
stabilizing the behavior of ultrafast lasers.Comment: 4 pages, 4 figures, to be published in Physical Review Letter
Controlling spatiotemporal chaos in oscillatory reaction-diffusion systems by time-delay autosynchronization
Diffusion-induced turbulence in spatially extended oscillatory media near a
supercritical Hopf bifurcation can be controlled by applying global time-delay
autosynchronization. We consider the complex Ginzburg-Landau equation in the
Benjamin-Feir unstable regime and analytically investigate the stability of
uniform oscillations depending on the feedback parameters. We show that a
noninvasive stabilization of uniform oscillations is not possible in this type
of systems. The synchronization diagram in the plane spanned by the feedback
parameters is derived. Numerical simulations confirm the analytical results and
give additional information on the spatiotemporal dynamics of the system close
to complete synchronization.Comment: 19 pages, 10 figures submitted to Physica
Controlling Chimeras
Coupled phase oscillators model a variety of dynamical phenomena in nature
and technological applications. Non-local coupling gives rise to chimera states
which are characterized by a distinct part of phase-synchronized oscillators
while the remaining ones move incoherently. Here, we apply the idea of control
to chimera states: using gradient dynamics to exploit drift of a chimera, it
will attain any desired target position. Through control, chimera states become
functionally relevant; for example, the controlled position of localized
synchrony may encode information and perform computations. Since functional
aspects are crucial in (neuro-)biology and technology, the localized
synchronization of a chimera state becomes accessible to develop novel
applications. Based on gradient dynamics, our control strategy applies to any
suitable observable and can be generalized to arbitrary dimensions. Thus, the
applicability of chimera control goes beyond chimera states in non-locally
coupled systems
Spatio-Temporal Patterns act as Computational Mechanisms governing Emergent behavior in Robotic Swarms
open access articleOur goal is to control a robotic swarm without removing its swarm-like nature. In other words, we aim to intrinsically control a robotic swarm emergent behavior. Past attempts at governing robotic swarms or their selfcoordinating emergent behavior, has proven ineffective, largely due to the swarm’s inherent randomness (making it difficult to predict) and utter simplicity (they lack a leader, any kind of centralized control, long-range communication, global knowledge, complex internal models and only operate on a couple of basic, reactive rules). The main problem is that emergent phenomena itself is not fully understood, despite being at the forefront of current research. Research into 1D and 2D Cellular Automata has uncovered a hidden computational layer which bridges the micromacro gap (i.e., how individual behaviors at the micro-level influence the global behaviors on the macro-level). We hypothesize that there also lie embedded computational mechanisms at the heart of a robotic swarm’s emergent behavior. To test this theory, we proceeded to simulate robotic swarms (represented as both particles and dynamic networks) and then designed local rules to induce various types of intelligent, emergent behaviors (as well as designing genetic algorithms to evolve robotic swarms with emergent behaviors). Finally, we analysed these robotic swarms and successfully confirmed our hypothesis; analyzing their developments and interactions over time revealed various forms of embedded spatiotemporal patterns which store, propagate and parallel process information across the swarm according to some internal, collision-based logic (solving the mystery of how simple robots are able to self-coordinate and allow global behaviors to emerge across the swarm)
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