Browsing by Subject "Chaos synchronization"

Now showing 1 - 8 of 8

Open Access
A chaotic masking scheme by using synchronized chaotic systems
(Elsevier, 1999) Morgül, Ö.; Feki, M.
We present a new chaotic masking scheme by using synchronized chaotic systems. In this method, synchronization and message transmission phases are separated, and while synchronization is achieved in the synchronization phases, the message is only sent in message transmission phases. We show that if synchronization is achieved exponentially fast, then under certain conditions any message of any length could be transmitted and successfully recovered provided that the synchronization length is sufficiently long. We also show that the proposed scheme is robust with respect to noise and parameter mismatch under some mild conditions.
Open Access
Model based anticontrol of discrete-time systems
(IEEE, 2003) Morgül, Ömer
We will consider a model-based approach for the anticontrol of some discrete-time systems. We first assume the existence of a chaotic model in an appropriate form. Then by using an appropriate control input we try to match the controlled system with the chaotic system model.
Open Access
A model-based scheme for anticontrol of some chaotic systems
(World Scientific Publishing, 2003) Morgül, Ö.
We consider a model-based approach for the anticontrol of some continuous time systems. We assume the existence of a chaotic model in an appropriate form. By using a suitable input, we match the dynamics of the controlled system and the chaotic model. We show that controllable systems can be chaotifled with the proposed method. We give a procedure to generate such chaotic models. We also apply an observer-based synchronization scheme to compute the required input.
Open Access
A model-based scheme for anticontrol of some discrete-time chaotic systems
(World Scientific, 2004) Morgül, Ö.
We consider a model-based approach for the anticontrol of some discrete-time systems. We first assume the existence of a chaotic model in an appropriate form. Then by using an appropriate control input we try to match the controlled system with the chaotic system model. We also give a procedure to generate the model chaotic systems in arbitrary dimensions. We show that with this approach, controllable systems can always be chaotified. Moreover, if the system to be controlled is stable, control input can be chosen arbitrarily small.
Open Access
Observability and observers for nonlinear and switching systems
(2001-08) Solak, Ercan
Open Access
Observer based chaotic message transmission
(World Scientific Publishing, 2003) Morgül, Ö.; Solak, E.; Akgül, M.
We consider observer based synchronization of continuous-time chaotic systems. We present two message transmission schemes for such systems. The first one is based on chaotic masking and modulation, and the second one is based on only chaotic modulation. We show that in these schemes, the message may be recovered under certain conditions. We show that the proposed schemes are robust with respect to noise and parameter mismatch. We also present some simulation results.
Open Access
Observer-based control of a class of chaotic systems
(Elsevier, 2001) Solak, E.; Morgül, O.; Ersoy, U.
We consider the control of a class of chaotic systems, which covers the forced chaotic oscillators. We focus on two control problems. The first one is to change the dynamics of the system to a new one which exhibits a desired behavior, and the second one is the tracking problem, i.e., to force the solutions of the chaotic system to track a given trajectory. To solve these problems we use observers which could be used to estimate the unknown states of the system to be controlled. We apply the proposed method to the control of Duffing equation and the Van der Pol oscillator and present some simulation results. © 2001 Elsevier Science B.V.
Open Access
Synchronization of chaotic systems by using occasional coupling
(1997) Feki, Moez
Nonlinear and chaotic systems are difficult to control due to their unstable and unpredictable nature. Although, much work has been done in this area, synchronization of chaotic systems still remains a worthwhile endeavor. In this thesis, a method to synchronize systems, inherently operating in a chaotic mode, by using occasional coupling is presented. We assume that a masterslave synchronizing scheme is available. This approach consists of coupling and uncoupling the drive and response systems during some alternated intervals. It is then shown how this synchronization method can be used to transmit information on a chaotic carrier. The applicability of this method will be illustrated using Lorenz system as the chaotic oscillator.