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1.
Locally and globally exponential stability of synchronization in asymmetrically nonlinear coupled networks and linear coupled networks are investigated in this paper, respectively. Some new synchronization stability criteria based on eigenvalues are derived. In these criteria, both a term that is the second largest eigenvalue of a symmetrical matrix and a term that is the largest value of the sum of the column of the asymmetrical coupling matrix play a key role. Comparing with existing results, the advantage of our synchronization stability results is that they can be analytically applied to the asymmetrically coupled networks and can overcome the complexity of calculating eigenvalues of the coupling asymmetric matrix. Therefore, these conditions are very convenient to use. Moreover, a necessary condition of globally exponential synchronization stability criterion is also given by the elements of the coupling asymmetric matrix, which can conveniently be used in judging the synchronization stability condition without calculating the eigenvalues of the coupling matrix. 相似文献
2.
Li Z 《Chaos (Woodbury, N.Y.)》2008,18(2):023124
Based on the original definition of the synchronization stability, a general framework is presented for investigating the exponential stability of synchronization in asymmetrically coupled networks. By choosing an appropriate Lyapunov function, we prove that the mechanism of the exponential synchronization stability is the asymmetrical coupling matrix with diffusive condition. We deduce the second largest eigenvalue of a symmetric matrix to govern the exponential stability of synchronization in asymmetrically coupled networks. Moreover, we have given the threshold value which can guarantee that the states of the asymmetrically coupled network achieve the exponential stability of synchronization. 相似文献
3.
Global synchronization of general delayed dynamical networks with linear coupling are investigated. A sufficient condition for the global synchronization is obtained by using the linear matrix inequality and introducing a reference state. This condition is simply given based on the maximum nonzero eigenvalue of the network coupling matrix. Moreover, we show how to construct the coupling matrix to guarantee global synchronization of network, which is very convenient to use. A two-dimension system with delay as a dynamical node in network with global coupling is finally presented to verify the theoretical results of the proposed global synchronization scheme. 相似文献
4.
A new general complex delayed dynamical network model with nonsymmetric coupling is introduced, and then we investigate its synchronization phenomena. Several synchronization criteria for delay-independent and delay-dependent synchronization are provided which generalize some previous results. The matrix Jordan canonical formalization method is used instead of the matrix diagonalization method, so in our synchronization criteria, the coupling configuration matrix of the network does not required to be diagonalizable and may have complex eigenvalues. Especially, we show clearly that the synchronizability of a delayed dynamical network is not always characterized by the second-largest eigenvalue even though all the eigenvalues of the coupling configuration matrix are real. Furthermore, the effects of time-delay on synchronizability of networks with unidirectional coupling are studied under some typical network structures. The results are illustrated by delayed networks in which each node is a two-dimensional limit cycle oscillator system consisting of a two-cell cellular neural network, numerical simulations show that these networks can realize synchronization with smaller time-delay, and will lose synchronization when the time-delay increase larger than a threshold. 相似文献
5.
We study global stability of synchronization in asymmetrically connected networks of limit-cycle or chaotic oscillators. We extend the connection graph stability method to directed graphs with node balance, the property that all nodes in the network have equal input and output weight sums. We obtain the same upper bound for synchronization in asymmetrically connected networks as in the network with a symmetrized matrix, provided that the condition of node balance is satisfied. In terms of graphs, the symmetrization operation amounts to replacing each directed edge by an undirected edge of half the coupling strength. It should be stressed that without node balance this property in general does not hold. 相似文献
6.
We present a network model with a new coupled scheme which is the generalization of drive-response systems called a drivingly coupled network. The synchronization of the network is investigated by numerical simulations based on Lorenz systems. By calculating the largest transversal Lyapunov exponents of such network, the stable and unstable regions of synchronous state for eigenvalues in such network can be obtained and many kinds of drivingly coupled arrays based on Lorenz systems such as all-to-all, star-shape, ring-shape and chain-shape networks are considered. 相似文献
7.
Based on the work of Nishikawa and Motter, who have extended the well-known master stability framework to include non-diagonalizable cases, we develop another extension of the master stability framework to obtain criteria for global synchronization. Several criteria for global synchronization are provided which generalize some previous results. The Jordan canonical transformation method is used in stead of the matrix diagonalization method. Especially, we show clearly that, the synchronizability of a dynamical network with nonsymmetric coupling is not always characterized by its second-largest eigenvalue, even though all the eigenvalues of the nonsymmetric coupling matrix are real. Furthermore, the effects of the asymmetry of coupling on synchronizability of networks with different structures are analyzed. Numerical simulations are also done to illustrate and verify the theoretical results on networks in which each node is a dynamical limit cycle oscillator consisting of a two-cell cellular neural network. 相似文献
8.
Pinning-controlled synchronization of complex networks with bounded or unbounded synchronized regions 下载免费PDF全文
This paper studies pinning-controlled synchronization of complex
networks with bounded or unbounded synchronized regions. To study a
state-feedback pinning-controlled network with N nodes, it first
converts the controlled network to an extended network of N+1
nodes without controls. It is shown that the controlled
synchronizability of the given network is determined by the real
part of the smallest nonzero eigenvalue of the coupling matrix of
its extended network when the synchronized region is unbounded; but
it is determined by the ratio of the real parts of the largest and
the smallest nonzero eigenvalues of the coupling matrix when the
synchronized region is bounded. Both theoretical analysis and
numerical simulation show that the portion of controlled nodes has
no critical values when the synchronized region is unbounded, but it
has a critical value when the synchronized region is bounded. In the
former case, therefore, it is possible to control the network to
achieve synchronization by pinning only one node. In the latter
case, the network can achieve controlled synchronization only when
the portion of controlled nodes is larger than the critical value. 相似文献
9.
We investigated the topological properties of stock networks constructed by a minimal spanning tree. We compared the original stock network with the estimated network; the original network is obtained by the actual stock returns, while the estimated network is the correlation matrix created by random matrix theory. We found that the consistency between the two networks increases as more eigenvalues are considered. In addition, we suggested that the largest eigenvalue has a significant influence on the formation of stock networks. 相似文献
10.
WANG Hai-Xia LU Qi-Shao WANG Qing-Yun 《理论物理通讯》2009,51(3):475-478
We investigate synchronization in an array network of nearest-neighbor coupled chaotic oscillators. By using of the Lyapunov stability theory and matrix theory, a criterion for stability of complete synchronization is deduced. Meanwhile, an estimate of the critical coupling strength is obtained to ensure achieving chaos synchronization. As an example application, a model of coupled Chua's circuits with linearly bidirectional coupling is studied to verify the validity of the criterion. 相似文献
11.
G. Yan Z. -Q. Fu G. Chen 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,63(4):515-520
We study the consensus dynamics with or without time-delays on directed and undirected de Bruijn graphs. Our results show
that consensus on an undirected de Bruijn graph has a lower converging speed and larger time-delay tolerance in comparison
with that on an undirected scale-free network. Although there is not much difference between the eigenvalue ratios of the
two undirected networks, we found that their dynamical properties are remarkably different; consequently, it is seemingly
more informative to consider the second smallest and the largest eigenvalues separately rather than considering their ratio
in the study of synchronization of a coupled oscillators network. Moreover, our study on directed de Bruijn graphs reveals
that properly setting directions on edges can improve the converging speed and time-delay tolerance simultaneously. 相似文献
12.
Synchronization analysis for nonlinearly-coupled complex networks with an asymmetrical coupling matrix 总被引:2,自引:0,他引:2
In this paper, the global synchronization for an array of nonlinearly coupled identical chaotic systems is investigated. A distinctive feature of this work is to address synchronization issues for nonlinearly coupled complex networks with an asymmetrical coupling matrix. By projecting the nonlinear coupling function onto a linear one and assuming the difference between them as a disturbing function, we give some criteria for the global synchronization in virtual of the left eigenvector corresponding to the zero eigenvalue of the coupling matrix. Numerical examples are also provided to demonstrate the effectiveness of the theory. 相似文献
13.
This paper investigates the global synchronization in an array of
linearly coupled neural networks with constant and delayed coupling.
By a simple combination of adaptive control and linear feedback with
the updated laws, some sufficient conditions are derived for global
synchronization of the coupled neural networks. The coupling
configuration matrix is assumed to be asymmetric, which is more
coincident with the realistic network. It is shown that the
approaches developed here extend and improve the earlier works.
Finally, numerical simulations are presented to demonstrate the
effectiveness of the theoretical results. 相似文献
14.
15.
Global synchronization in arrays of coupled networks with one single time-varying delay coupling is investigated in this Letter. A general linear coupled network with a time-varying coupling delay is proposed and its global synchronization is further discussed. Some sufficient criteria are derived based on Lyapunov functional and linear matrix inequality (LMI). It is shown that under one single delay coupling, the synchronized state changes, which is different from the conventional synchronized solution. Moreover, the degree of the nodes and the inner delayed coupling matrix play key roles in the synchronized state. In particular, the derivative of the time-varying delay can be any given value. Finally, numerical simulations are given to illustrate the theoretical results. 相似文献
16.
N. Fujiwara J. Kurths 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(1):45-49
We employ a spectral decomposition method to
analyze synchronization of a non-identical oscillator network.
We study the case that a small parameter mismatch
of oscillators is characterized by one parameter
and phase synchronization is observed.
We derive a linearized equation for each eigenmode of the coupling matrix.
The parameter mismatch
is reflected on inhomogeneous term in the linearized equation.
We find that the
oscillation of each mode is essentially characterized only by
the eigenvalue of the coupling matrix with a suitable normalization.
We refer to this property as spectral universality,
because it is observed irrespective of network topology.
Numerical results in various network topologies
show good agreement with those based on linearized equation.
This universality is also observed in a system
driven by additive independent Gaussian noise. 相似文献
17.
18.
Global synchronization of Chua's chaotic delay network by using linear matrix inequality 总被引:3,自引:0,他引:3 下载免费PDF全文
Global synchronization of Chua‘s chaotic dynamical networks with coupling delays is investigated in this paper.Unlike other approaches, where only local results were obtained, the network is found to be not linearized in this paper.Insteat, the global synchronization is obtained by using the linear matrix inequality theory. Moreover, some quite simple linear-state-error feedback controllers for global synchronization are derived, which can be easily constructed based on the minimum eigenvalue of the coupling matrix. A simulation of Chua‘s chaotic network with global coupling delays in nodes is finally given, which is used to verify the theoretical results of the proposed global synchron izationscheme. 相似文献
19.
In this Letter, we study the exponential stochastic synchronization problem for coupled neural networks with stochastic noise perturbations. Based on Lyapunov stability theory, inequality techniques, the properties of Weiner process, and adding different intermittent controllers, several sufficient conditions are obtained to ensure exponential stochastic synchronization of coupled neural networks with or without coupling delays under stochastic perturbations. These stochastic synchronization criteria are expressed in terms of several lower-dimensional linear matrix inequalities (LMIs) and can be easily verified. Moreover, the results of this Letter are applicable to both directed and undirected weighted networks. A numerical example and its simulations are offered to show the effectiveness of our new results. 相似文献
20.
非线性耦合超混沌R(o)ssler系统和网络的同步 总被引:4,自引:0,他引:4
研究两个通过非线性函数对称耦合的超混沌Roessler系统的同步问题.通过对超混沌系统的线性项与非线性项的适当分离,构造一个特殊的非线性函数,作为耦合函数,发现在耦合强度α=0.5附近的一小段区域里存在稳定的超混沌同步现象.利用线性系统的稳定性分析准则和条件Lyapunov指数来检验同步状态的稳定性,并进一步研究了由多个超混沌Roessler系统单元通过非线性函数按照完全连接形式组成的网络的混沌同步问题。显示许多耦合单元组成的网络,满足同步稳定性的耦合强度的取值范围可以仅从2个单元组成的网络的参数取值范围估计到。此外发现耦合强度的值与耦合单元数量成反比,数值模拟结果证实所提出方法对超混沌系统和网络的混沌同步是有效的。 相似文献