Impulsive synchronization seeking in general complex delayed dynamical networks

The present paper investigates the issues of impulsive synchronization seeking in general complex delayed dynamical networks with nonsymmetrical coupling. By establishing the extended Halanay differential inequality on impulsive delayed dynamical systems, some simple yet generic sufficient conditions for global exponential synchronization of the impulsive controlled delayed dynamical networks are derived analytically. Compared with some existing works, the distinctive features of these sufficient conditions indicate two aspects: on the one hand, these sufficient conditions can provide an effective impulsive control scheme to synchronize an arbitrary given delayed dynamical network to a desired synchronization state even if the original given network may be asynchronous itself. On the other hand, the controlled synchronization state can be selected as a weighted average of all the states in the network for the purpose of practical control strategy, which reveals the contributions and influences of various nodes in synchronization seeking processes of the dynamical networks. It is shown that impulses play an important role in making the delayed dynamical networks globally exponentially synchronized. Furthermore, the results are applied to a typical nearest-neighbor unidirectional time-delay coupled networks composed of chaotic FHN neuron oscillators, and numerical simulations are given to demonstrate the effectiveness of the proposed control methodology.     

Impulsive synchronization of general continuous and discrete-time complex dynamical networks

This paper mainly investigates the impulsive synchronization of a general complex continuous and discrete-time dynamical network. Firstly, for the continuous complex networks, we give a sufficient condition to guarantee its synchronization. When the sufficient condition is not satisfied, the impulsive controllers are utilized, and some novel criteria are derived to guarantee the network synchronization in this case. What is more significant is that the similar work is extended to the discrete-time networks model. Finally, the results are, respectively, illustrated by a continuous network composed with the chaotic Chen oscillators and a discrete-time network consisting of Hénon map. All numerical simulations verify the effectiveness of the theoretical analysis.     

Impulsive synchronization of time-varying dynamical network

Synchronization of time-varying dynamical network is investigated via impulsive control. Based on the Lyapunov function method and stability theory of impulsive differential equation, a synchronization criterion with respect to the system parameters and the impulsive gains and intervals is analytically derived. Further, an adaptive strategy is introduced for designing unified impulsive controllers, with a corresponding synchronization criterion derived. In this proposed adaptive control scheme, the impulsive instants adjust themselves to the needed values as time goes on, and an algorithm for determining the impulsive instants is provided and evaluated. The derived theoretical results are illustrated to be effective by several numerical examples.     

Impulsive generalized synchronization for a class of nonlinear discrete chaotic systems

The problem of impulsive generalized synchronization for a class of nonlinear discrete chaotic systems is investigated in this paper. Firstly the response system is constructed based on the impulsive control theory. Then by the asymptotic stability criteria of discrete systems with impulsive effects, some sufficient conditions for asymptotic H-synchronization between the drive system and response system are obtained. Numerical simulations are given to show the effectiveness of the proposed method.     

Chaotic synchronization of two complex nonlinear oscillators

Synchronization is an important phenomenon commonly observed in nature. It is also often artificially induced because it is desirable for a variety of applications in physics, applied sciences and engineering. In a recent paper [Mahmoud GM, Mohamed AA, Aly SA. Strange attractors and chaos control in periodically forced complex Duffing’s oscillators. Physica A 2001;292:193–206], a system of periodically forced complex Duffing’s oscillators was introduced and shown to display chaotic behavior and possess strange attractors. Such complex oscillators appear in many problems of physics and engineering, as, for example, nonlinear optics, deep-water wave theory, plasma physics and bimolecular dynamics. Their connection to solutions of the nonlinear Schrödinger equation has also been pointed out.In this paper, we study the remarkable phenomenon of chaotic synchronization on these oscillator systems, using active control and global synchronization techniques. We derive analytical expressions for control functions and show that the dynamics of error evolution is globally stable, by constructing appropriate Lyapunov functions. This means that, for a relatively large set initial conditions, the differences between the drive and response systems vanish exponentially and synchronization is achieved. Numerical results are obtained to test the validity of the analytical expressions and illustrate the efficiency of these techniques for inducing chaos synchronization in our nonlinear oscillators.     

Adaptive pinning synchronization of a class of nonlinearly coupled complex networks

This paper is concerned with the pinning control of the robust synchronization of a class of nonlinearly coupled complex networks through adaptive techniques. The effect of perturbed couplings is addressed by adaptive compensation and adjustment methods with controllers and coupling strength designs, respectively. For the pinned nodes, a controller gain function is proposed to compensate the nonlinearities based on adaptive estimations of controller parameters on-line; while for the un-pinned nodes, adaptive adjustment laws are addressed to adjust unknown coupling factors to restrain the unexpected action of the nonlinearly coupled networks. On the basis of Lyapunov stability theory, adaptive pinning controllers and coupling strength adjusters are constructed to ensure that the synchronization errors of the networks can be reduced as small as desired in the presence of the nonlinear couplings. A numerical simulation is provided to illustrate the effectiveness of the theoretical results.     

Identification of nonlinear dynamics using a general spatio-temporal network

The so-called spatio-temporal neural network is considered. This is a neural network where the conventional weight multiplication operation is replaced by a linear filtering operation. General learning algorithms are derived for such a network, both in the discrete-time and in the continuous-time domains. The problem of deterministic nonlinear system identification is considered as an application of spatio-temporal neural networks. Nonlinear system identification is one of the challenging problems in the field of dynamic systems, with limited successful results using conventional methods. Neural network approaches have so far been encouraging, but further exploration is needed. The capabilities of the derived algorithms and of the considered architectures to effectively identify deterministic nonlinear systems is demonstrated through examples.     

Periodic two-cluster synchronization modes in fully coupled networks of nonlinear oscillators

Theoretical and Mathematical Physics - We consider special systems of ordinary differential equations, the so-called fully coupled networks of nonlinear oscillators. For a given class of systems,...     

An intriguing hybrid synchronization phenomenon of two coupled complex networks

This paper investigates the hybrid synchronization problem of two coupled complex networks. Employing the linear feedback and the adaptive feedback control methods which are simple, efficient, and easy to implement in practical applications, we obtain some useful criteria of the hybrid synchronization of two coupled networks based on the Lyapunov stability theory and Lasalle’s invariance principle. It shows that under suitable conditions, two coupled complex networks can realize an intriguing hybrid synchronization: the outer anti-synchronization between the driving network and the response network, and the inner complete synchronization in the driving network and the response network, respectively. Numerical simulations demonstrate the effectiveness of the proposed hybrid synchronization scheme.     

Guaranteed cost synchronization of a complex dynamical network via dynamic feedback control

In this paper, the problem of guaranteed cost synchronization for a complex network is investigated. In order to achieve the synchronization, two types of guaranteed cost dynamic feedback controller are designed. Based on Lyapunov stability theory, a linear matrix inequality (LMI) convex optimization problem is formulated to find the controller which guarantees the asymptotic stability and minimizes the upper bound of a given quadratic cost function. Finally, a numerical example is given to illustrate the proposed method.     

Complex complete synchronization of two nonidentical hyperchaotic complex nonlinear systems

In this paper, we introduce the definition of complex complete synchronization (CCS) of hyperchaotic complex nonlinear systems that have not been introduced recently in the literature. This type of synchronization can study only for complex nonlinear systems. On the basis of Lyapunov function, a scheme is designed to achieve the CCS of two nonidentical hyperchaotic attractors of these systems. The effectiveness of the obtained results is illustrated by a simulation example. Numerical results are plotted to show state variables, modules errors, and phases errors of these hyperchaotic attractors after synchronization to prove that CCS is achieved. Copyright © 2013 John Wiley & Sons, Ltd.     

Impulsive synchronization for a chaotic system with channel time-delay

This paper discusses the synchronization of the chaotic system. Some new and less conservative sufficient conditions are established by impulsive control method with channel time-delay and different time-varying parameter uncertainties. An example and its simulations are finally included to visualize the effectiveness and feasibility of the method.     

非等谱广义耦合非线性Schrodinger方程的局部化孤立波

利用Hirota双线性方法求解了一个非等谱广义耦合非线性Schrodinger方程,得到它的Ⅳ一孤子解．其中单孤子可以描述一个任意大振幅且具有时间和空间双重局部性的孤立波,这种特征与所谓的“怪波”相一致．此外,借助于图像描述了二孤子的相互作用．     

Chaos synchronization in general complex dynamical networks with coupling delays

On the basis of Lyapunov stability theory, chaos synchronization of a general complex dynamical network with coupling delays is investigated. Some delay-independent and delay-dependent criteria for exponential synchronization are derived via adopting the free weighting matrix approach; these are less conservative than those previously reported. As an example, the upper bound of the coupling delay for a Duffing system is obtained, and is larger than those reported previously. Finally, some simulation results obtained with different outer-coupling matrices are given to demonstrate the effectiveness of the results that we obtained, and these are compared with existing conclusions to show the advantage of our results.     

Generalized outer synchronization between non-dissipatively coupled complex networks with different-dimensional nodes

This paper investigates the generalized outer synchronization (GOS) between two non-dissipatively coupled complex dynamical networks (CDNs) with different time-varying coupling delays. Our drive-response networks also possess nonlinear inner coupling functions and time-varying outer coupling configuration matrices. Besides, in our network models, the nodes in the same network are nonidentical and the nodes in different networks have different state dimensions. Asymptotic generalized outer synchronization (AGOS) and exponential generalized outer synchronization (EGOS) are defined for our CDNs. Our main objective in this paper is to design AGOS and EGOS controllers for our drive-response networks via the open-plus-closed-loop control technique. Distinguished from most existing literatures, it is the partial intrinsic dynamics of each node in response network that is restricted by the QUAD condition, which is easy to be satisfied. Representative simulation examples are given to verify the effectiveness and feasibility of our GOS theoretical results in this paper.     

Analytical solution for general nonlinear continuous systems in a complex form

In this paper, the method of multiple scales is used to study free vibrations and primary resonances of geometrically nonlinear spatial continuous systems with general quadratic and cubic nonlinear operators in a complex form. It is found that in the free vibrations of general continuous systems in a complex form, both forward and backward modes are excited. This situation is in contrast to the primary resonances in which only forward modes are excited. Consequently, one may determine the form of solution before applying the multiple scales method to the equation. This analysis is applicable to general continuous systems with gyroscopic and Coriolis effects and includes many nonlinear problems as a special case. As an example of application of this general solution, free vibrations and primary resonances of a simply supported rotating shaft with stretching nonlinearity are considered.     

Chaotic synchronization of two coupled neurons via nonlinear control in external electrical stimulation

The chaotic synchronization to two electrical coupled neurons via nonlinear control is investigated. The coupled model is based on the nonlinear cable model and the two neurons are coupled with gap junction. If the controller were not applied, the synchronization would occur only when the couple strength of gap junction satisfied some condition. Using techniques from modern control theory, a nonlinear controller can be obtained that result in two of coupled neurons being synchronized with each other without needing to consider the couple strength of gap junction. The detailed derivation that leads to the nonlinear controller and numerical results that verify the controller’s ability to synchronize the two neurons together are included.     

Global synchronization of nonlinearly coupled complex networks with non-delayed and delayed coupling

This paper investigates the global synchronization of nonlinearly coupled complex networks with non-delayed and delayed coupling using methods that are based on pinning control. Sufficient conditions for global synchronization are obtained by applying suitable feedback or adaptive feedback controllers to certain selected nodes and numerical examples are provided to demonstrate the effectiveness of the theory.     

Adaptive synchronization of two nonlinearly coupled complex dynamical networks with delayed coupling

This paper investigates the adaptive synchronization between two nonlinearly delay-coupled complex networks with the bidirectional actions and nonidentical topological structures. Based on LaSalle’s invariance principle, some criteria for the synchronization between two coupled complex networks are achieved via adaptive control. To validate the proposed methods, the unified chaotic system as the nodes of the networks are analyzed in detail, and numerical simulations are given to illustrate the theoretical results.     

Impulsive stabilization of nonlinear systems

In this paper, we investigate the impulsive stabilization ofnonlinear systems by employing Lyapunov's direct method. Sufficientconditions for both stabilization and destabilization are obtained.Some examples are also worked out which demonstrate the sharpnessof the conditions.