Physica A 387 (2008) 5616–5622
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Physica A
journal homepage: www.elsevier.com/locate/physa
Synchronization in a class of weighted complex networks with coupling
delays
Qingyun Wang
a,b,∗
, Zhisheng Duan
a
, Guanrong Chen
a,c
, Zhaosheng Feng
d
a
State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering,
College of Engineering, Peking University, Beijing 100871, China
b
School of Statistics and Mathematics, Inner Mongolia Finance and Economics College, Huhhot 010051, China
c
Department of Electronic Engineering, City University of Hong Kong, Hong Kong, China
d
Department of Mathematics, University of Texas-Pan American, Edinburg, TX 78539, USA
a r t i c l e i n f o
Article history:
Received 12 December 2007
Received in revised form 27 February 2008
Available online 12 June 2008
PACS:
84.35.+i
05.45.+b
05.45.Xt
Keywords:
Weighted complex networks
Coupling delays
Synchronization stability
a b s t r a c t
It is commonly accepted that realistic networks can display not only a complex topological
structure, but also a heterogeneous distribution of connection weights. In addition, time
delay is inevitable because the information spreading through a complex network is
characterized by the finite speeds of signal transmission over a distance. Weighted complex
networks with coupling delays have been gaining increasing attention in various fields
of science and engineering. Some of the topics of most concern in the field of weighted
complex networks are finding how the synchronizability depends on various parameters
of the network including the coupling strength, weight distribution and delay. On the basis
of the theory of asymptotic stability of linear time-delay systems with complex coefficients,
the synchronization stability of weighted complex dynamical networks with coupling
delays is investigated, and simple criteria are obtained for both delay-independent and
delay-dependent stabilities of the synchronization state. Finally, an example is given as an
illustration testing the theoretical results.
© 2008 Elsevier B.V. All rights reserved.
1. Introduction
The complex networks have been gaining increasing recognition as a fundamental tool in understanding dynamical
behavior and the response of real systems coming from different fields such as biology, social systems, linguistic networks,
and technological systems [1–7]. The dynamics of complex networks has been extensively investigated, with special
emphasis on the interplay between the complexity in the overall topology and the local dynamical properties of the coupled
nodes. As a typical kind of dynamics, synchronization in complex networks has become of significant interest in recent
years. Of particular interest is how the synchronization ability depends on various parameters of the network, such as
average distance, clustering coefficient, coupling strength, degree distribution and weight distribution. The dependence
of the emergent collective phenomena on the coupling strength and on the topology was unveiled for homogeneous and
heterogeneous complex networks [8]. A somewhat surprising finding is that a scale-free network, while having smaller
network distances than a small-world network of the same size, is actually more difficult to synchronize [9]. It is shown
in Ref. [10] that in the presence of some proper gradient fields, scale-free networks can be more synchronizable than
homogeneous networks. The average degree of the network is the key to synchronization and, under certain conditions,
∗
Corresponding author at: State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of
Engineering, Peking University, Beijing 100871, China. Tel.: +86 1082317963; fax: +86 1082317963.
E-mail address: nmqingyun@163.com (Q. Wang).
0378-4371/$ – see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.physa.2008.05.056