共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
In this paper, the networks with optimal synchronizability are obtained using the local structure information. In scale-free networks, a node will be coupled by its neighbors with maximal degree among the neighbors if and only if the maximal degree is larger than its own degree. If the obtained coupled networks are connected, they are synchronization optimal networks. The connection probability of coupled networks is greatly affected by the average degree which usually increases with the average degree. This method could be further generalized by taking into account the degree of next-nearest neighbors, which will sharply increase the connection probability. Compared to the other proposed methods that obtain synchronization optimal networks, our method uses only local structure information and can hold the structure properties of the original scale-free networks to some extent. Our method may present a useful way to manipulate the synchronizability of real-world scale-free networks. 相似文献
3.
Cluster synchronization in the adaptive complex dynamical networks via a novel approach 总被引:2,自引:0,他引:2
This Letter investigates cluster synchronization in the adaptive complex dynamical networks with nonidentical nodes by a local control method and a novel adaptive strategy for the coupling strengths of the networks. In this approach, the coupling strength of each node adjusts adaptively only based on the state information of its neighborhood. By means of the proposed scheme, the sufficient conditions for achieving cluster synchronization are derived analytically by utilizing Lyapunov stability theory. It is demonstrated that the synchronization performance is sensitively affected by the control gain, the inner-coupling matrix and the network topological structure. The numerical simulations are performed to verify the effectiveness of the theoretical results. 相似文献
4.
We review our recent work on the synchronization of a network of delay-coupled maps, focusing on the interplay of the network
topology and the delay times that take into account the finite velocity of propagation of interactions. We assume that the
elements of the network are identical (N logistic maps in the regime where the individual maps, without coupling, evolve in a chaotic orbit) and that the coupling
strengths are uniform throughout the network. We show that if the delay times are sufficiently heterogeneous, for adequate
coupling strength the network synchronizes in a spatially homogeneous steady state, which is unstable for the individual maps
without coupling. This synchronization behavior is referred to as ‘suppression of chaos by random delays’ and is in contrast
with the synchronization when all the interaction delay times are homogeneous, because with homogeneous delays the network
synchronizes in a state where the elements display in-phase time-periodic or chaotic oscillations. We analyze the influence
of the network topology considering four different types of networks: two regular (a ring-type and a ring-type with a central
node) and two random (free-scale Barabasi-Albert and small-world Newman-Watts). We find that when the delay times are sufficiently
heterogeneous the synchronization behavior is largely independent of the network topology but depends on the network’s connectivity,
i.e., on the average number of neighbors per node.
相似文献
5.
We present and experimentally demonstrate a technique for achieving and maintaining a global state of identical synchrony of an arbitrary network of chaotic oscillators even when the coupling strengths are unknown and time-varying. At each node an adaptive synchronization algorithm dynamically estimates the current strength of the net coupling signal to that node. We experimentally demonstrate this scheme in a network of three bidirectionally coupled chaotic optoelectronic feedback loops and we present numerical simulations showing its application in larger networks. The stability of the synchronous state for arbitrary coupling topologies is analyzed via a master stability function approach. 相似文献
6.
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
7.
Complete and phase synchronization in a heterogeneous small-world neuronal network 总被引:1,自引:0,他引:1 下载免费PDF全文
Synchronous firing of neurons is thought to be important for
information communication in neuronal networks. This paper
investigates the complete and phase synchronization in a
heterogeneous small-world chaotic Hindmarsh--Rose neuronal network.
The effects of various network parameters on synchronization
behaviour are discussed with some biological explanations. Complete
synchronization of small-world neuronal networks is studied
theoretically by the master stability function method. It is shown
that the coupling strength necessary for complete or phase
synchronization decreases with the neuron number, the node degree
and the connection density are increased. The effect of
heterogeneity of neuronal networks is also considered and it is
found that the network heterogeneity has an adverse effect on
synchrony. 相似文献
8.
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
9.
This paper studies how phase synchronization in complex networks
depends on random shortcuts, using the piecewise-continuous chaotic
Chua system as the nodes of the networks. It is found that for a
given coupling strength, when the number of random shortcuts is
greater than a threshold the phase synchronization is induced. Phase
synchronization becomes evident and reaches its maximum as the
number of random shortcuts is further increased. These phenomena
imply that random shortcuts can induce and enhance the phase
synchronization in complex Chua systems. Furthermore, the paper
also investigates the effects of the coupling strength and it is
found that stronger coupling makes it easier to obtain the
complete phase synchronization. 相似文献
10.
M. Zhao T. Zhou B.-H. Wang Q. Ou J. Ren 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,53(3):375-379
In this paper, inspired by the idea that different nodes should
play different roles in network synchronization, we bring forward
a coupling method where the coupling strength of each node depends
on its neighbors' degrees. Compared with the uniform coupled
method and the recently proposed Motter-Zhou-Kurths method, the
synchronizability of scale-free networks can be remarkably
enhanced by using the present coupling method, and the highest
network synchronizability is achieved at β=1 which is
similar to a method introduced in [AIP Conf. Proc. 776, 201
(2005)]. 相似文献
11.
This paper investigates generalized synchronization of three typical classes of complex dynamical networks: scale-free networks, small-world networks, and interpolating networks. The proposed synchronization strategy is to adjust adaptively a node’s coupling strength based on the node’s local generalized synchronization information. By taking the auxiliary-system approach and using the Lyapunov function method, we prove that for any given initial coupling strengths, the generalized synchronization can take place in complex networks consisting of nonidentical dynamical systems. It is demonstrated that the coupling strengths are affected by topologies of the networks. Furthermore, it is found that there are hierarchical features in the processes of generalized synchronization in scale-free networks because of their highly heterogeneous distributions of connection degree. Finally, we discuss in detail how a network’s degree of heterogeneity affects its generalization synchronization behavior. 相似文献
12.
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
13.
We study the self-organization of phase synchronization in coupled map scale-free networks with chaotic logistic map at each node and find that a variety of ordered spatiotemporal patterns emerge spontaneously in a regime of coupling strength. These ordered behaviours will change with the increase of the average finks and are robust to both the system size and parameter mismatch. A heuristic theory is given to explain the mechanism of self-organization and to figure out the regime of coupling for the ordered spatiotemporal patterns. 相似文献
14.
M. Ponce C. C. Masoller Arturo C. Martí 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,67(1):83-93
We study a network of coupled logistic maps whose interactions occur with a certain distribution of delay times. The local
dynamics is chaotic in the absence of coupling and thus the network is a paradigm of a complex system. There are two regimes
of synchronization, depending on the distribution of delays: when the delays are sufficiently heterogeneous the network synchronizes
on a steady-state (that is unstable for the uncoupled maps); when the delays are homogeneous, it synchronizes in a time-dependent
state (that is either periodic or chaotic). Using two global indicators we quantify the synchronizability on the two regimes,
focusing on the roles of the network connectivity and the topology. The connectivity is measured in terms of the average number
of links per node, and we consider various topologies (scale-free, small-world, star, and nearest-neighbor with and without
a central hub). With weak connectivity and weak coupling strength, the network displays an irregular oscillatory dynamics
that is largely independent of the topology and of the delay distribution. With heterogeneous delays, we find a threshold
connectivity level below which the network does not synchronize, regardless of the network size. This minimum average number
of neighbors seems to be independent of the delay distribution. We also analyze the effect of self-feedback loops and find
that they have an impact on the synchronizability of small networks with large coupling strengths. The influence of feedback,
enhancing or degrading synchronization, depends on the topology and on the distribution of delays. 相似文献
15.
《Physics letters. A》2020,384(35):126881
Recently, the explosive synchronization (ES) has attracted great interests. Motivated by the recent dynamic framework of complex network, we focus on the network of mobile oscillators and study synchronization phenomenon. The local synchronous order parameter of the neighbors of the oscillator is used as the controllable variable to adjust the coupling strength of the oscillator. Hence, it can be seen as a kind of adaptive strategy. By numerical simulation, we find that ES can be observed in the dynamic network of mobile oscillators, accompanying with hysteresis loop, as the coupling strength increases gradually. It is found that the critical value of coupling strength and hysteresis loop width is affected by the natural frequency distribution and the number of neighbors the oscillator owning. It can be deduced that ES will be motivated by increasing the number of oscillators in the network. Meanwhile, our results are feasible to different natural frequency distributions, such as Lorentzian, Gaussian power-law, and Rayleigh distribution, whether it is symmetric or not. 相似文献
16.
采用Br-Eiswirth模型研究了两层耦合可激发介质中螺旋波的动力学,两层介质通过网络连接,即在每一层介质上,每一列选一个可激发单元作为中心点,在一层介质上同一列的可激发单元只与另一层介质上对应的中心点及其8个邻居有耦合.数值模拟结果表明:通过这种局部耦合,在适当小的耦合强度下两耦合螺旋波可实现同步,增大耦合强度会导致螺旋波漫游和漂移,造成螺旋波不同步,观察到螺旋波与静息态、低频平面波和不规则斑图共存现象.在适当强的耦合强度下,还观察到两螺旋波转变成同步的平面波消失现象.对产生这些现象的物理机理做了讨论. 相似文献
17.
随着复杂网络同步的进一步发展,对复杂网络的研究重点由单层网络转向更加接近实际网络的多层有向网络.本文分别严格推导出三层、多层的单向耦合星形网络的特征值谱,并分析了耦合强度、节点数、层数对网络同步能力的影响,重点分析了层数和层间中心节点之间的耦合强度对多层单向耦合星形网络同步能力的影响,得出了层数对多层网络同步能力的影响至关重要.当同步域无界时,网络的同步能力与耦合强度、层数有关,同步能力随其增大而增强;当同步域有界时,对于叶子节点向中心节点耦合的多层星形网络,当层内耦合强度较弱时,层内耦合强度的增大会使同步能力增强,而层间叶子节点之间的耦合强度、层数的增大反而会使同步能力减弱;当层间中心节点之间的耦合强度较弱时,层间中心节点之间的耦合强度、层数的增大会使同步能力增强,层内耦合强度、层间叶子节点之间的耦合强度的增大反而会使同步能力减弱.对于中心节点向叶子节点耦合的多层星形网络,层间叶子节点之间的耦合强度、层数的增大会使同步能力增强,层内耦合强度、节点数、层间中心节点之间的耦合强度的增大反而会使同步能力减弱. 相似文献
18.
We study the effect of noise on the outer synchronization between two unidirectionally coupled complex networks and find analytically that outer synchronization could be achieved via white-noise-based coupling. It is also demonstrated that, if two networks have both conventional linear coupling and white-noise-based coupling, the critical deterministic coupling strength between two complex networks for synchronization transition decreases with an increase in the intensity of noise. We provide numerical results to illustrate the feasibility and effectiveness of the theoretical results. 相似文献
19.
This paper explores the intra-layer synchronization in duplex networks with different topologies within layers and different inner coupling patterns between, within, and across layers. Based on the Lyapunov stability method, we prove theoretically that the duplex network can achieve intra-layer synchronization under some appropriate conditions, and give the thresholds of coupling strength within layers for different types of inner coupling matrices across layers. Interestingly,for a certain class of coupling matrices across layers, it needs larger coupling strength within layers to ensure the intra-layer synchronization when the coupling strength across layers become larger, intuitively opposing the fact that the intra-layer synchronization is seemly independent of the coupling strength across layers. Finally, numerical simulations further verify the theoretical results. 相似文献
20.
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