共查询到20条相似文献,搜索用时 15 毫秒
1.
B. Wang T. Zhou Z. L. Xiu B. J. Kim 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(1):89-95
We numerically investigate how to enhance
synchronizability of coupled identical oscillators in complex
networks with research focus on the roles of the high level of
clustering for a given heterogeneity in the degree distribution.
By using the edge-exchange method with the fixed degree sequence, we
first directly maximize synchronizability measured by the
eigenratio of the coupling matrix, through the use of the so-called
memory tabu search algorithm developed in applied mathematics. The
resulting optimal network, which turns out to be weakly
disassortative, is observed to exhibit a small modularity. More
importantly, it is clearly revealed that the optimally
synchronizable network for a given degree sequence shows a very low
level of clustering, containing much fewer small-size loops than the
original network. We then use the clustering coefficient as an
object function to be reduced during the edge exchanges, and find it
a very efficient way to enhance synchronizability. We thus
conclude that under the condition of a given degree heterogeneity,
the clustering plays a very important role in the network synchronization. 相似文献
2.
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
3.
The concept of edge weight provides additional depth for describing and adjusting the properties of networks. Redistribution of edge weight can effectively change the properties of networks even though the corresponding binary topology remains unchanged. Based on regular networks with initially homogeneous dissimilarity weights, random redistribution of edge weight can be enough to induce small world phenomena. The effects of random weight redistribution on both static properties and dynamical models of networks are investigated. The results reveal that randomization of weight can enhance the ability of synchronization of chaotic systems dramatically. 相似文献
4.
L. Wang H. P. Dai H. Dong Y. Y. Cao Y. X. Sun 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(3):335-342
This paper considers the problem of controlling
weighted complex dynamical networks by applying adaptive control
to a fraction of network nodes. We investigate the local and
global synchronization of the controlled dynamical network through
the construction of a master stability function and a Lyapunov
function. Analytical results show that a certain number of nodes
can be controlled by using adaptive pinning to ensure the
synchronization of the entire network. We present numerical
simulations to verify the effectiveness of the proposed scheme. In
comparison with feedback pinning, the proposed pinning control
scheme is robust when tested by noise, different weighting and
coupling structures, and time delays. 相似文献
5.
Shihong Wang Junzhong Yang 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(1):81-92
Generalized synchronization in a drive-response Chua circuits is investigated. A cascade of transitions to GS is observed
with increasing the interaction strength. The mechanism on the
transitions to GS is given based on the asymptotic behaviors of response dynamics. 相似文献
6.
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
7.
A. Pluchino A. Rapisarda V. Latora 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,65(3):395-402
We have recently introduced [Phys. Rev. E 75, 045102(R) (2007); AIP Conference Proceedings 965, 2007, p. 323] an efficient method for the detection and identification of modules in complex networks, based on the de-synchronization
properties (dynamical clustering) of phase oscillators. In this paper we apply the dynamical clustering tecnique to the identification
of communities of marine organisms living in the Chesapeake Bay food web. We show that our algorithm is able to perform a
very reliable classification of the real communities existing in this ecosystem by using different kinds of dynamical oscillators.
We compare also our results with those of other methods for the detection of community structures in complex networks. 相似文献
8.
L. Wang F. Du H. P. Dai Y. X. Sun 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,53(3):361-366
A random pseudofractal network (RPN) is generated by a
recursive growing rule. The RPN is of the scale-free feature and
small-world effect. We obtain the theoretical results of power-law
exponent γ=3, clustering coefficient C=3π2-19≈
0.74, and a proof that the mean distance increases no faster than
ln N, where N is the network size. These results agree with
the numerical simulation very well. In particular, we explain the
property of growth and preferential attachment in RPNs. And the
properties of a class of general RPNs are discussed in the end. 相似文献
9.
N. Gupte B. K. Singh 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):227-230
We study network traffic dynamics in a two dimensional communication
network
with regular nodes and hubs.
If the network experiences heavy message traffic, congestion occurs due
to finite
capacity of the nodes. We discuss strategies to manipulate hub
capacity and hub
connections to relieve congestion and define a coefficient of
betweenness centrality
(CBC), a direct measure of network traffic, which is useful for
identifying hubs which
are most likely to cause congestion. The addition of assortative
connections to hubs
of high CBC relieves congestion very efficiently.
An erratum to this article is available at . 相似文献
10.
11.
In this Letter, we propose a growing network model that can generate scale-free networks with a tunable community strength. The community strength, C, is directly measured by the ratio of the number of external edges to that of the internal ones; a smaller C corresponds to a stronger community structure. By using the Kuramoto model, we investigated the phase synchronization on this network and found an abnormal region (C?0.002), in which the network has even worse synchronizability than the unconnected case (C=0). On the other hand, the community effect will vanish when C exceeds 0.1. Between these two extreme regions, a stronger community structure will hinder global synchronization. 相似文献
12.
C. Fretter B. Drossel 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(3):365-371
We evaluate the probability that a Boolean network returns to an
attractor after perturbing h nodes. We find that the return
probability as function of h can display a variety of different
behaviours, which yields insights into the state-space structure. In
addition to performing computer simulations, we derive analytical
results for several types of Boolean networks, in particular for
Random Boolean Networks. We also apply our method to networks that have
been evolved for robustness to small perturbations, and to a biological example. 相似文献
13.
S. Carmi Z. Wu E. López S. Havlin H. Eugene Stanley 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(2):165-174
We study the transport properties of model networks such as
scale-free and Erd?s-Rényi networks as well as a real
network. We consider few possibilities for the trnasport problem.
We start by studying the conductance G between two arbitrarily
chosen nodes where each link has the same unit resistance. Our
theoretical analysis for scale-free networks predicts a broad
range of values of G, with a power-law tail distribution
$\Phi_{\rm SF}(G)\sim G^{-g_G}$
, where gG=2λ-1, and
λ is the decay exponent for the scale-free network degree
distribution. The power-law tail in ΦSF(G) leads to
large values of G, thereby significantly improving the transport
in scale-free networks, compared to Erd?s-Rényi networks
where the tail of the conductivity distribution decays
exponentially. We develop a simple physical picture of the
transport to account for the results. The other model for
transport is the max-flow model, where conductance is defined
as the number of link-independent paths between the two nodes, and
find that a similar picture holds. The effects of distance on the
value of conductance are considered for both models, and some
differences emerge. We then extend our study to the case of
multiple sources ans sinks, where the transport is defined between two
groups of nodes. We find a fundamental difference between
the two forms of flow when considering the quality of the
transport with respect to the number of sources, and find an
optimal number of sources, or users, for the max-flow case. A
qualitative (and partially quantitative) explanation is also
given. 相似文献
14.
M. N. Kuperman M. Ballard F. Laguna 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(3):513-520
A model for a dynamic network consisting of changing
local interactions is presented in this work. While the network
maintains solely local connections, certain properties known only
to Small World Networks may be extracted due to the dynamic nature
of the model. At each time step the individuals are grouped into
clusters creating neighborhoods or domains of fully connected
agents. The boundaries of these domains change in time,
corresponding to a situation where the links between individuals
are dynamic only throughout the history of the network. A question
that we pose is whether our model, which maintains a local
structure such that diffusion calculations are possible, might
lead to analytic or conceptual advances for the much more
complicated case of diffusion on a static disordered network that
exhibits the same macroscopic properties as our dynamic
ordered network. To answer this, we compare certain properties
which characterize the dynamic domain network to those of a Small
World Network, and then analyze the diffusion coefficients for
three possible domain mutations. We close with a comparison and
confirmation of previous epidemiological work carried out on
networks. 相似文献
15.
Synchronization processes in populations of locally interacting elements are the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understanding synchronization phenomena in natural systems now take advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also take an overview of the new emergent features coming out from the interplay between the structure and the function of the underlying patterns of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences. 相似文献
16.
G. Ghoshal M. E.J. Newman 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(2):175-184
We consider distributed networks, such as peer-to-peer networks, whose
structure can be manipulated by adjusting the rules by which vertices
enter and leave the network. We focus in particular on degree
distributions and show that, with some mild constraints, it is possible
by a suitable choice of rules to arrange for the network to have any
degree distribution we desire. We also describe a mechanism based on
biased random walks by which appropriate rules could be implemented in
practice. As an example application, we describe and simulate the
construction of a peer-to-peer network optimized to minimize search times
and bandwidth requirements. 相似文献
17.
Markus Brede 《Physics letters. A》2008,372(15):2618-2622
In this Letter we discuss a method for generating synchrony-optimized coupling architectures of Kuramoto oscillators with a heterogeneous distribution of native frequencies. The method allows us to relate the properties of the coupling network to its synchronizability. These relations were previously only established from a linear stability analysis of the identical oscillator case. We further demonstrate that the heterogeneity in the oscillator population produces heterogeneity in the optimal coupling network as well. Two rules for enhancing the synchronizability of a given network by a suitable placement of oscillators are given: (i) native frequencies of adjacent oscillators must be anti-correlated and (ii) frequency magnitudes should positively correlate with the degree of the node they are placed at. 相似文献
18.
S. Lehmann L. K. Hansen 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,60(1):83-88
We study community structure of networks. We have developed a scheme
for maximizing the modularity Q [Newman and Girvan, Phys. Rev. E 69, 026113 (2004)] based on mean field methods. Further, we have defined a simple family of random networks with community structure;
we understand the behavior of
these networks analytically. Using these networks, we show how the
mean field methods display better performance than previously known
deterministic methods for optimization of Q. 相似文献
19.
A limited resource model of fault-tolerant capability
against cascading failure of complex network 总被引:1,自引:0,他引:1
P. Li B.-H. Wang H. Sun P. Gao T. Zhou 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(1):101-104
We propose a novel capacity model for complex networks
against cascading failure. In this model, vertices with both higher
loads and larger degrees should be paid more extra capacities, i.e.
the allocation of extra capacity on vertex i will be proportional
to ki
γ , where ki is the degree of vertex i
and γ > 0 is a free parameter. We have applied this model on
Barabási-Albert network as well as two real transportation
networks, and found that under the same amount of available
resource, this model can achieve better network robustness than
previous models. 相似文献
20.
This Letter considers the problem of controlling a weighted complex dynamical network with coupling time-varying delay toward an assigned evolution. Adaptive controllers have been designed for nodes of the controlled network. Analytical results show that the states of the weighted dynamical network can globally asymptotically synchronize onto a desired orbit under the designed controllers. In comparison with the common linear feedback controllers, the adaptive controllers have strong robustness against asymmetric coupling matrix, time-varying weights, delays, and noise. Numerical simulations illustrated by a nearest-neighbor coupling network verify the effectiveness of the proposed controllers. 相似文献