Extracting Communities from Complex Networks by the k-Dense Method

Kazumi SAITO  Takeshi YAMADA  Kazuhiro KAZAMA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E91-A   No.11   pp.3304-3311
Publication Date: 2008/11/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e91-a.11.3304
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Graphs and Networks
complex network,  community extraction,  k-core,  k-clique,  k-dense,  

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To understand the structural and functional properties of large-scale complex networks, it is crucial to efficiently extract a set of cohesive subnetworks as communities. There have been proposed several such community extraction methods in the literature, including the classical k-core decomposition method and, more recently, the k-clique based community extraction method. The k-core method, although computationally efficient, is often not powerful enough for uncovering a detailed community structure and it produces only coarse-grained and loosely connected communities. The k-clique method, on the other hand, can extract fine-grained and tightly connected communities but requires a substantial amount of computational load for large-scale complex networks. In this paper, we present a new notion of a subnetwork called k-dense, and propose an efficient algorithm for extracting k-dense communities. We applied our method to the three different types of networks assembled from real data, namely, from blog trackbacks, word associations and Wikipedia references, and demonstrated that the k-dense method could extract communities almost as efficiently as the k-core method, while the qualities of the extracted communities are comparable to those obtained by the k-clique method.