BlackHole: Robust community detection inspired by graph drawing

With regard to social network analysis, we concentrate on two widely-accepted building blocks: community detection and graph drawing. Although community detection and graph drawing have been studied separately, they have a great commonality, which means that it is possible to advance one field using the techniques of the other. In this paper, we propose a novel community detection algorithm for undirected graphs, called BlackHole, by importing a geometric embedding technique from graph drawing. Our proposed algorithm transforms the vertices of a graph to a set of points on a low-dimensional space whose coordinates are determined by a variant of graph drawing algorithms, following the overall procedure of spectral clustering. The set of points are then clustered using a conventional clustering algorithm to form communities. Our primary contribution is to prove that a common idea in graph drawing, which is characterized by consideration of repulsive forces in addition to attractive forces, improves the clusterability of an embedding. As a result, our algorithm has the advantages of being robust especially when the community structure is not easily detectable. Through extensive experiments, we have shown that BlackHole achieves the accuracy higher than or comparable to the state-of-the-art algorithms.