Community Extraction Based on Density-first Search and Its Application to Bid Data

Abstract

In this research, we propose a new biclustering method for extracting communities from binary matrices which represent a binary relation. A binary relation can be represented as a bipartite graph or a binary matrix. Many effective clustering methods for extracting communities from graphs and matrices have been proposed. In this paper, the objective data is a bid data which represent a participation record of companies in bids. A community in bid data means a set of companies which often participated in multiple bids. We aim at applying the community extraction to finding bid rigging groups. In order to achieve the goal, we propose a biclustering method based on the density of bipartite graphs and the characteristic extraction by the nonnegative matrix factorization.