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1.
Synchronizability of complex oscillators networks has attracted much
research interest in recent years. In contrast, in this paper we
investigate numerically the synchronization speed, rather than the
synchronizability or synchronization stability, of identical
oscillators on complex networks with communities. A new weighted
community network model is employed here, in which the community
strength could be tunable by one parameter δ. The results
showed that the synchronization speed of identical oscillators on
community networks could reach a maximal value when δ is
around 0.1. We argue that this is induced by the competition
between the community partition and the scale-free property of the
networks. Moreover, we have given the corresponding analysis through
the second least eigenvalue λ2 of the Laplacian matrix of
the network which supports the previous result that the
synchronization speed is determined by the value of λ2. 相似文献
2.
Zheng Zhi-gang Feng Xiao-qin Ao Bin Michael C. Cross 《Frontiers of Physics in China》2006,1(4):458-467
In this paper, partial synchronization (PaS) in networks of coupled chaotic oscillator systems and synchronization in sparsely
coupled spatiotemporal systems are explored. For the PaS, we reveal that the existence of PaS patterns depends on the symmetry
property of the network topology, while the emergence of the PaS pattern depends crucially on the stability of the corresponding
solution. An analytical criterion in judging the stability of PaS state on a given network are proposed in terms of a comparison
between the Lyapunov exponent spectrum of the PaS manifold and that of the transversal manifold. The competition and selections
of the PaS patterns induced by the presence of multiple topological symmetries of the network are studied in terms of the
criterion. The phase diagram in distinguishing the synchronous and the asynchronous states is given. The criterion in judging
PaS is further applied to the study of synchronization of two sparsely coupled spatiotemporal chaotic systems. Different synchronization
regimes are distinguished. The present study reveals the intrinsic collective bifurcation of coupled dynamical systems prior
to the emergence of global synchronization. 相似文献
3.
针对具有随机节点结构的复杂网络, 研究其同步问题. 基于Lyapunov稳定性理论和线性矩阵不等式技术给出了复杂网络同步稳定的充分性条件, 该充分性条件不仅与复杂网络的状态时延有关, 还与节点结构的概率分布有关. 数值仿真表明本文方法的有效性.
关键词:
复杂网络
随机节点
同步稳定
时滞 相似文献
4.
In this paper, we propose a simple model that can generate
small-world network with community structure. The network is
introduced as a tunable community organization with parameter r,
which is directly measured by the ratio of inter- to intra-community
connectivity, and a smaller r corresponds to a stronger community
structure. The structure properties, including the degree
distribution, clustering, the communication efficiency and
modularity are also analysed for the network. In addition, by using
the Kuramoto model, we investigated the phase synchronization on
this network, and found that increasing the fuzziness of community
structure will markedly enhance the network synchronizability;
however, in an abnormal region (r ≤ 0.001), the network has even
worse synchronizability than the case of isolated communities (r =
0). Furthermore, this network exhibits a remarkable
synchronization behaviour in topological scales: the oscillators of
high densely interconnected communities synchronize more easily, and
more rapidly than the whole network. 相似文献
5.
We investigate the synchronization of complex networks,which are impulsively coupled only at discrete instants.Based on the comparison theory of impulsive differential systems,a distributed impulsive control scheme is proposed for complex dynamical networks to achieve synchronization.The proposed scheme not only takes into account the influence of all nodes to network synchronization,which depends on the weight of each node in the network,but also provides us with a flexible method to select the synchronized state of the network.In addition,it is unnecessary for the impulsive coupling matrix to be symmetrical.Finally,the proposed control scheme is applied to a chaotic Lorenz network and Chua’s circuit network.Numerical simulations are used to illustrate the validity of this control scheme. 相似文献
6.
Many realistic networks have community structures, namely, a network
consists of groups of nodes within which links are dense but among
which links are sparse. This paper proposes a growing network model
based on local processes, the addition of new nodes intra-community
and new links intra- or inter-community. Also, it utilizes the
preferential attachment for building connections determined by
nodes' strengths, which evolves dynamically during the growth of the
system. The resulting network reflects the intrinsic community
structure with generalized power-law distributions of nodes' degrees
and strengths. 相似文献
7.
Some scalar linear controllers, which can ensure that the states of coupled chaotic dynamical networks asymptotically synchronize each other, are derived on the basis of high gain state feedback control. Numerical simulation is given to validate the proposed theoretical result. 相似文献
8.
9.
Synchronization and coherence of chaotic Morris--Lecar (ML) neural networks have
been investigated by numerical methods. The synchronization of the neurons can be
enhanced by increasing the number of the shortcuts, even though all neurons are
chaotic when uncoupled. Moreover, the coherence of the neurons exhibits a
non-monotonic dependence on the density of shortcuts. There is an optimal number of
shortcuts at which the neurons' motion is most ordered, i.e. the order parameter
(the characteristic correlation time) that is introduced to measure the coherence of
the neurons has a maximum. These phenomena imply that stochastic shortcuts can tame
spatiotemporal chaos. The effects of the coupling strength have also been studied.
The value of the optimal number of shortcuts goes down as the coupling strength
increases. 相似文献
10.
This paper proposes new delay-dependent synchronization criteria for coupled Hopfield neural networks with time-varying delays. By construction of a suitable Lyapunov-Krasovskii's functional and use of Finsler's lemma, novel synchronization criteria for the networks are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. Two numerical examples are given to illustrate the effectiveness of the proposed methods. 相似文献
11.
In this paper, we propose a simple random network model with overlapping communities controlled by several parameters, and investigate the influence of the overlapping community structure on the synchronization behavior under different parameters. It is found that the synchronizability of the network is mainly influenced by the overlapping size of the communities and the connectivity density of the overlapped group to the other interrelated communities, and has nothing to do with the intra-connectivity of the overlapped group. In addition, it is found that the highly interconnected communities can be almost synchronized in a given time scale, whereas the overlapped group is far from synchronization. Furthermore, the instantaneous frequencies of the nodes in the communities and their overlapped group are also investigated, which show that the nodes in the overlapped group will exhibit a remarkable oscillation with a weighted mean frequency of the other correlative communities. 相似文献
12.
This Letter focuses on the synchronization in a class of dynamical complex networks with each node being a deterministic ratchet. In virtue of the technique derived from pendulum-like nonlinear analytic theory and Kalman–Yakubovich–Popov (KYP) lemma, simple linear matrix inequality (LMI) formulations are established to guarantee the stable synchronization of such networks. An interesting conclusion is reached that the stability of synchronization in the coupled whole N-dimensional networks can be converted into that of the simplest 2-dimensional space. 相似文献
13.
利用既有效又便于实施的时滞状态反馈控制器,根据所给定的条件构造相应的不等式,研究了带有时滞的离散神经网络模型的同步控制问题,给出了该离散系统指数同步的充分条件.在设计同步控制的时候,没有假设激励函数的有界性、可微性和单调性,给出的条件简便易实施.数值结果进一步证明了该控制方法的有效性.
关键词:
离散神经网络
时滞
同步 相似文献
14.
Synchronization of complex community networks with nonidentical nodes and adaptive coupling strength
In this Letter, the complex dynamical networks with community structure and nonidentical nodes are considered. The globally asymptotical synchronization of the time-delayed complex community networks onto any uniformly smooth state is studied. Some simple and useful criteria are derived by constructing an effective control scheme and adjusting automatically the adaptive coupling strength. Finally, the developed techniques are applied to two complex community networks which are respectively synchronized to a chaotic trajectory and a periodic orbit, and numerical simulations are provided to show the feasibility of the developed methods. 相似文献
15.
评估复杂网络系统的节点重要性有助于提升其系统抗毁性和结构稳定性. 目前, 定量节点重要性的排序算法通常基于网络结构的中心性指标如度数、介数、紧密度、特征向量等. 然而, 这些算法需要以知晓网络结构的全局信息为前提, 很难在大规模网络中实际应用. 基于自规避随机游走的思想, 提出一种结合网络结构局域信息和标签扩散的节点排序算法. 该算法综合考虑了节点的直接邻居数量及与其他节点之间的拓扑关系, 能够表征其在复杂网络系统中的结构影响力和重要性. 基于三个典型的实际网络, 通过对极大连通系数、网络谱距离数、节点连边数和脆弱系数等评估指标的实验对比, 结果表明提出的算法显著优于现有的依据局域信息的节点排序算法. 相似文献
16.
Huang Liang Lai Ying-Cheng Kwangho Park Wang Xingang Lai Choy Heng Robert A. Gatenby 《Frontiers of Physics in China》2007,2(4):446-459
Synchronization in complex networks has been an active area of research in recent years. While much effort has been devoted
to networks with the small-world and scale-free topology, structurally they are often assumed to have a single, densely connected
component. Recently it has also become apparent that many networks in social, biological, and technological systems are clustered,
as characterized by a number (or a hierarchy) of sparsely linked clusters, each with dense and complex internal connections.
Synchronization is fundamental to the dynamics and functions of complex clustered networks, but this problem has just begun
to be addressed. This paper reviews some progress in this direction by focusing on the interplay between the clustered topology
and network synchronizability. In particular, there are two parameters characterizing a clustered network: the intra-cluster
and the inter-cluster link density. Our goal is to clarify the roles of these parameters in shaping network synchronizability.
By using theoretical analysis and direct numerical simulations of oscillator networks, it is demonstrated that clustered networks
with random inter-cluster links are more synchronizable, and synchronization can be optimized when inter-cluster and intra-cluster
links match. The latter result has one counterintuitive implication: more links, if placed improperly, can actually lead to
destruction of synchronization, even though such links tend to decrease the average network distance. It is hoped that this
review will help attract attention to the fundamental problem of clustered structures/synchronization in network science.
相似文献
17.
Cascades with coupled map lattices in preferential attachment community networks 总被引:2,自引:0,他引:2 下载免费PDF全文
In this paper, cascading failure is studied by coupled map lattice (CML) methods in preferential attachment community networks. It is found that external perturbation R is increasing with modularity Q growing by simulation. In particular, the large modularity Q can hold off the cascading failure dynamic process in community networks. Furthermore, different attack strategies also greatly affect the cascading failure dynamic process. It is particularly significant to control cascading failure process in real community networks. 相似文献
18.
Synchronization of stochastically hybrid coupled neural networks with coupling discrete and distributed time-varying delays 下载免费PDF全文
A general model of linearly stochastically coupled identical connected neural networks with hybrid coupling is proposed, which is composed of constant coupling, coupling discrete time-varying delay and coupling distributed timevarying delay. All the coupling terms are subjected to stochastic disturbances described in terms of Brownian motion, which reflects a more realistic dynamical behaviour of coupled systems in practice. Based on a simple adaptive feedback controller and stochastic stability theory, several sufficient criteria are presented to ensure the synchronization of linearly stochastically coupled complex networks with coupling mixed time-varying delays. Finally, numerical simulations illustrated by scale-free complex networks verify the effectiveness of the proposed controllers. 相似文献
19.
This Letter presents an analytical study of synchronization in an array of coupled deterministic Boolean networks. A necessary and sufficient criterion for synchronization is established based on algebraic representations of logical dynamics in terms of the semi-tensor product of matrices. Some basic properties of a synchronized array of Boolean networks are then derived for the existence of transient states and the upper bound of the number of fixed points. Particularly, an interesting consequence indicates that a “large” mismatch between two coupled Boolean networks in the array may result in loss of synchrony in the entire system. Examples, including the Boolean model of coupled oscillations in the cell cycle, are given to illustrate the present results. 相似文献
20.
Impulsive synchronization of two coupled complex networks with time-delayed dynamical nodes 下载免费PDF全文
In this paper, we investigate the impulsive synchronization between two coupled complex networks with time-delayed dynamical nodes. Based on the Lyapunov stability, the linear feedback control and the impulsive control theories, the linear feedback and the impulsive controllers are designed separately. By using the generalized Barbalat's lemma, the global asymptotic impulsive synchronization of the drive—response complex networks is derived and some corresponding sufficient conditions are also obtained. Numerical examples are presented to verify the effectiveness and the correctness of the synchronization criteria. 相似文献