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1.
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.
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2.
针对由两个子网络构成的耦合含时滞的相互依存网络,研究其局部自适应异质同步问题.时滞同时存在于两个子网络的内部耦合项和子网络间的一对一相互依赖耦合项中,且网络的耦合关系满足非线性特性和光滑性.基于李雅普诺夫稳定性理论、线性矩阵不等式方法和自适应控制技术,通过对子网络设置合适的控制器,提出了使得相互依存网络的子网络分别同步到异质孤立系统的充分条件.针对小世界网络和无标度网络构成的相互依存网络进行数值模拟,验证了提出理论的正确性和有效性. 相似文献
3.
In this paper we briefly report some recent developments on generalized synchronization. We discuss different methods of detecting generalized synchronization. We first consider two unidirectionally coupled systems and then two mutually coupled systems. We then extend the study to a network of coupled systems. In the study of generalized synchronization of coupled nonidentical systems we discuss the Master Stability Function (MSF) formalism for coupled nearly identical systems. Later we use this MSF to construct synchronized optimized networks. In the optimized networks the nodes which have parameter value at one extreme are chosen as hubs and the pair of nodes with larger difference in parameter are chosen to create links. 相似文献
4.
Adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions
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<正>The adaptive generalized matrix projective lag synchronization between two different complex networks with non-identical nodes and different dimensions is investigated in this paper.Based on Lyapunov stability theory and Barbalat’s lemma,generalized matrix projective lag synchronization criteria are derived by using the adaptive control method.Furthermore,each network can be undirected or directed,connected or disconnected,and nodes in either network may have identical or different dynamics.The proposed strategy is applicable to almost all kinds of complex networks.In addition,numerical simulation results are presented to illustrate the effectiveness of this method,showing that the synchronization speed is sensitively influenced by the adaptive law strength,the network size,and the network topological structure. 相似文献
5.
Recently, the researches on pinning control of complex dynamical networks have mainly focused on such networks with very specific coupling schemes (e.g., symmetric coupling, uniform coupling and linear coupling). However, most real networks often consist of local units, which interact with each other via asymmetric and heterogeneous connections. In this paper, pinning control of a continuous-time complex dynamical network with general coupling topologies is studied. Some generic stability criteria based on master stability function (MSF) are derived for such a general controlled network, which guarantee that the whole network can be pinned to its equilibrium by placing feedback control only on a small fraction of nodes. Then, these results are extended to discrete-time case. Previous results about symmetric, uniform or linear coupled networks in this area are included as special cases of the present work. Numerical simulations of directed networks with weighted coupling pinned by specifically selective pinning scheme are given for illustration and verification. 相似文献
6.
7.
Enhancing the network synchronizability 总被引:1,自引:0,他引:1
The structural and dynamical properties, particularly the small-world effect and scale-free feature, of complex networks have
attracted tremendous interest and attention in recent years. This article offers a brief review of one focal issue concerning
the structural and dynamical behaviors of complex network synchronization. In the presentation, the notions of synchronization
of dynamical systems on networks, stability of dynamical networks, and relationships between network structure and synchronizability,
will be first introduced. Then, various technical methods for enhancing the network synchronizability will be discussed, which
are roughly divided into two classes: Structural Modification and Coupling-Pattern Regulation, where the former includes three
typical methods—dividing hub nodes, shortening average distances, and deleting overload edges, while the latter mainly is
a method of strengthening the hub-nodes’ influence on the network.
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8.
Robust adaptive synchronization of uncertain and delayed dynamical complex networks with faulty network
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<正>This paper presents a new robust adaptive synchronization method for a class of uncertain dynamical complex networks with network failures and coupling time-varying delays.Adaptive schemes are proposed to adjust controller parameters for the faulty network compensations,as well as to estimate the upper and lower bounds of delayed state errors and perturbations to compensate the effects of delay and perturbation on-line without assuming symmetry or irreducibility of networks.It is shown that,through Lyapunov stability theory,distributed adaptive controllers constructed by the adaptive schemes are successful in ensuring the achievement of asymptotic synchronization of networks in the present of faulty and delayed networks,and perturbation inputs.A Chua's circuit network example is finally given to show the effectiveness of the proposed synchronization criteria. 相似文献
9.
The present paper is mainly concerned with the issues of synchronization dynamics of complex delayed dynamical networks with impulsive effects. A general model of complex delayed dynamical networks with impulsive effects is formulated, which can well describe practical architectures of more realistic complex networks related to impulsive effects. Based on impulsive stability theory on delayed dynamical systems, some simple but less conservative criterion are derived for global synchronization of such dynamical network. It is shown that synchronization of the networks is heavily dependent on impulsive effects of connecting configuration in the networks. Furthermore, the theoretical results are applied to a typical SF network composing of impulsive coupled chaotic delayed Hopfield neural network nodes, and are also illustrated by numerical simulations. 相似文献
10.
Motivated by the fact that couplings between individual units of many real-world complex systems are relevant to energy, we propose a power-driven moving agent network model as a simple representation. The presented network exhibits a directed and time-varying topological structure, where each agent associated with a chaotic oscillator is depicted as a random walker in a planar space, and interactions among agents are established via communication by assigning different emission powers to them. To investigate the effect of power distribution, synchronization is further explored for the power-driven moving agent network. Under the constraint of fast-switching, we theoretically show that synchronization of the agent network is determined by the power density which is independent of both the power distribution and the size of network. Several numerical simulations are given to validate the acquired results. 相似文献
11.
综述了非线性网络的动力学复杂性研究在网络理论、实证和应用方面所取得的主要进展和重要成果;深刻揭示了复杂网络的若干复杂性特征与基本定量规律;提出和建立了网络科学的统一混合理论体系(三部曲)和网络金字塔,并引入一类广义Farey组织的网络家族,阐明网络的复杂性-简单性与多样性-普适性之间转变关系;揭示了网络的拓扑结构特征与网络的动态特性之间关系;建立具有长程连接的规则网络的部分同步理论并应用于随机耦合的时空非线性系统的同步;提出复杂网络的动力学同步与控制多种方法;提出若干提高同步能力的模型、方法和途径,如同步最优和同步优先模型、同步与网络特征量关系、权重作用、叶子节点影响等;提出复杂混沌网络的多目标控制及具有小世界和无标度拓扑的束流输运网络的束晕-混沌控制方法;提出集群系统的自适应同步模型及蜂拥控制方法;探讨网络上拥塞与路由控制、资源博弈及不同类型网络上传播的若干规律;揭示含权经济科学家合作网及其演化特点;实证研究并揭示了多层次的高科技企业网和若干社会网络的特点;提出一种复杂网络的非平衡统计方法,把宏观网络推进到微观量子网络。 相似文献
12.
The main objective of the present paper is further to investigate global synchronization of a general model of complex delayed dynamical networks. Based on stability theory on delayed dynamical systems, some simple yet less conservative criteria for both delay-independent and delay-dependent global synchronization of the networks are derived analytically. It is shown that under some conditions, if the uncoupled dynamical node is stable itself, then the network can be globally synchronized for any coupling delays as long as the coupling strength is small enough. On the other hand, if each dynamical node of the network is chaotic, then global synchronization of the networks is heavily dependent on the effects of coupling delays in addition to the connection configuration. Furthermore, the results are applied to some typical small-world (SW) and scale-free (SF) complex networks composing of coupled dynamical nodes such as the cellular neural networks (CNNs) and the chaotic FHN neuron oscillators, and numerical simulations are given to verify and also visualize the theoretical results. 相似文献
13.
Kong-qing YANG Lei YANG Bai-hua GONG Zhong-cai LIN Hong-sheng HE Liang HUANG 《Frontiers of Physics in China》2008,3(1):105-111
Complex networks describe a wide range of systems in nature and society. Since most real systems exist in certain physical
space and the distance between the nodes has influence on the connections, it is helpful to study geographical complex networks
and to investigate how the geographical constrains on the connections affect the network properties. In this paper, we briefly
review our recent progress on geographical complex networks with respect of statistics, modelling, robustness, and synchronizability.
It has been shown that the geographical constrains tend to make the network less robust and less synchronizable. Synchronization
on random networks and clustered networks is also studied.
相似文献
14.
Synchronization in simple network motifs with negligible correlation and mutual information measures
Can different or even identical coupled oscillators be completely uncorrelated and still be synchronized? What can be concluded from the absence of correlations or even mutual information in networks of dynamical elements about their connectivity? These are fundamental and far-reaching questions arising in many complex systems. In this Letter, we address these two questions and demonstrate in simple and generic network motifs that synchronized behavior in the generalized sense can be realized and constructed such that no correlations and even negligible mutual information remain. Our findings raise new questions, in particular, whether and to what extent indirect connections are being underestimated, since the related collective behavior and even synchronization are less likely to be detected. 相似文献
15.
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
16.
In this paper, the problem of combination projection synchronization of fractional-order complex dynamic networks with time-varying delay couplings and external interferences is studied. Firstly, the definition of combination projection synchronization of fractional-order complex dynamic networks is given, and the synchronization problem of the drive-response systems is transformed into the stability problem of the error system. In addition, time-varying delays and disturbances are taken into consideration to make the network synchronization more practical and universal. Then, based on Lyapunov stability theory and fractional inequality theory, the adaptive controller is formulated to make the drive and response systems synchronization by the scaling factors. The controller is easier to realize because there is no time-delay term in the controller. At last, the corresponding simulation examples demonstrate the effectiveness of the proposed scheme. 相似文献
17.
Synchronization is a widespread phenomenon in both synthetic and real-world networks. This collective behavior of simple and complex systems has been attracting much research during the last decades. Two different routes to synchrony are defined in networks; first-order, characterized as explosive, and second-order, characterized as continuous transition. Although pioneer researches explained that the transition type is a generic feature in the networks, recent studies proposed some frameworks in which different phase and even chaotic oscillators exhibit explosive synchronization. The relationship between the structural properties of the network and the dynamical features of the oscillators is mainly proclaimed because some of these frameworks show abrupt transitions. Despite different theoretical analyses about the appearance of the first-order transition, studies are limited to the mean-field theory, which cannot be generalized to all networks. There are different real-world and man-made networks whose properties can be characterized in terms of explosive synchronization, e.g., the transition from unconsciousness to wakefulness in the brain and spontaneous synchronization of power-grid networks. In this review article, explosive synchronization is discussed from two main aspects. First, pioneer articles are categorized from the dynamical-structural framework point of view. Then, articles that considered different oscillators in the explosive synchronization frameworks are studied. In this article, the main focus is on the explosive synchronization in networks with chaotic and neuronal oscillators. Also, efforts have been made to consider the recent articles which proposed new frameworks of explosive synchronization. 相似文献
18.
There has been mounting evidence that many types of biological or technological networks possess a clustered structure. As many system functions depend on synchronization, it is important to investigate the synchronizability of complex clustered networks. Here we focus on one fundamental question: Under what condition can the network synchronizability be optimized? In particular, since the two basic parameters characterizing a complex clustered network are the probabilities of intercluster and intracluster connections, we investigate, in the corresponding two-dimensional parameter plane, regions where the network can be best synchronized. Our study yields a quite surprising finding: a complex clustered network is most synchronizable when the two probabilities match each other approximately. Mismatch, for instance caused by an overwhelming increase in the number of intracluster links, can counterintuitively suppress or even destroy synchronization, even though such an increase tends to reduce the average network distance. This phenomenon provides possible principles for optimal synchronization on complex clustered networks. We provide extensive numerical evidence and an analytic theory to establish the generality of this phenomenon. 相似文献
19.
Complex networks have established themselves in recent
years as being particularly suitable and flexible for representing
and modelling many complex natural and artificial systems.
Oil--water two-phase flow is one of the most complex systems. In
this paper, we use complex networks to study the inclined oil--water
two-phase flow. Two different complex network construction methods
are proposed to build two types of networks, i.e. the flow pattern
complex network (FPCN) and fluid dynamic complex network (FDCN).
Through detecting the community structure of FPCN by the
community-detection algorithm based on K-means clustering, useful
and interesting results are found which can be used for identifying
three inclined oil--water flow patterns. To investigate the dynamic
characteristics of the inclined oil--water two-phase flow, we construct
48 FDCNs under different flow conditions, and find that the
power-law exponent and the network information entropy, which are
sensitive to the flow pattern transition, can both characterize the
nonlinear dynamics of the inclined oil--water two-phase flow. In this
paper, from a new perspective, we not only introduce a complex
network theory into the study of the oil--water two-phase flow but also
indicate that the complex network may be a powerful tool for exploring
nonlinear time series in practice. 相似文献
20.
C. Grabow S. Grosskinsky M. Timme 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,84(4):613-626
Synchrony is one of the most common dynamical states emerging on networks. The speed of
convergence towards synchrony provides a fundamental collective time scale for
synchronizing systems. Here we study the asymptotic synchronization times for directed
networks with topologies ranging from completely ordered, grid-like, to completely
disordered, random, including intermediate, partially disordered topologies. We extend the
approach of master stability functions to quantify synchronization times. We find that the
synchronization times strongly and systematically depend on the network topology. In
particular, at fixed in-degree, stronger topological randomness induces faster
synchronization, whereas at fixed path length, synchronization is slowest for intermediate
randomness in the small-world regime. Randomly rewiring real-world neural, social and
transport networks confirms this picture. 相似文献