Physica A 392 (2013) 1902–1908
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Physica A
journal homepage: www.elsevier.com/locate/physa
Effects of community structure on navigation
Biao Wang
a
, Zhao Zhuo
a
, Shi-Min Cai
a,b,∗
, Zhong-Qian Fu
a
a
Department of Electronic Science and Technology, University of Science and Technology of China, Hefei Anhui, 230026, PR China
b
Web Sciences Center, School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu Sichuan, 611731, PR China
a r t i c l e i n f o
Article history:
Received 12 March 2012
Received in revised form 26 November
2012
Available online 9 January 2013
Keywords:
Navigation
Complex network
Latent space
Community
LMDS
a b s t r a c t
The dynamic behaviors of the complex network are crucially affected by its structural
properties, which is an essential issue that has attracted much interest. In this paper,
the effects of the community structure on the navigability of complex networks are
comprehensively investigated. The networks we explored, each of which is embedded
in a K-dimension Euclidean space based on a landmark based multi-dimensional scaling
(LMDS) algorithm, are of scale-free configuration with tunable modularity, obtained by
regulating the proportion of edges in and between communities. Pairs of source and
target are selected from the nodes in the networks, and the messages are passed along
from source to target in this space based on the greedy routing strategy. The extensive
experiments we carried out suggest that, the higher navigability, defined by proportion of
messages successfully delivered, is related to stronger modularity of the complex networks.
In addition, the optimal dimension K of the embedding Euclidean space is found to be
approximately identical to half of the landmark number.
© 2013 Elsevier B.V. All rights reserved.
1. Introduction
Navigation is one of the fundamental dynamical properties of networks. In the 1960s, a series of experiments conducted
by Travers and Milgram [1] unveiled that messages could be delivered to a destination through only a few people in the large-
scale social networks, in which nobody is aware of the whole information of the network structures. This phenomenon is
known as the small-world (SW) property. Recently, the SW phenomenon further confirmed that about twenty percent of
letters were successfully delivered with an average 4–5 hops in the experiments performed, both in email and online social
service networks, based on a greedy routing strategy [2–4]. Moreover, networks from the fields of nature and technology
also show similar properties revealed by several empirical works [5–7]. In light of the pervasiveness of the SW phenomenon
in various kinds of networks, it turns out to be important to interpret this phenomenon, and work has been carried out.
For instance, Watts and Strogatz [5] proposed a model of an SW network with characterization of low diameter and high
cluster coefficient by adding random connections on a regular network. Following that, Kleinberg defined an infinite family
of network models that naturally generalize the Watts–Strogatz model based on a decentralized algorithm, with which a
high probability can be achieved to find short paths [8]. On the other hand, the investigation of navigation (e.g. passing
messages) in complex networks has shown that the network topological properties, such as the SW property, the exponent
of power-law distribution, and the number of long range connections have effects on their navigability [8–11].
The aforementioned SW structure and power-law degree distribution have described the global properties of network
topology, however, the local environment of nodes in many real networks is also explored, such as the so-called community
structure [12–17]. In general, a community is defined as a subset of nodes in which connections are dense and among
∗
Corresponding author at: Department of Electronic Science and Technology, University of Science and Technology of China, Hefei Anhui, 230026,
PR China.
E-mail address: shimin.cai81@gmail.com (S.-M. Cai).
0378-4371/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
doi:10.1016/j.physa.2013.01.001