Analysis for Topological Properties of the Network Feeding Usenet News

Recently, many studies have reported that various kinds of real networks, such as WWW, the Internet, metabolic system, BtoB transactions and so on, have the scale-free properties in common. We focus on the network feeding Usenet news where a node represents a news server and a link between two nodes represents a connection on which the two news servers exchange their articles. First we generate the whole topology map approximately from path information of a number of Usenet news articles. Then we examine topological properties of the network; degree distribution, degree correlation, average distance, clustering coefficient and community structures. We also compare these properties with those of theoretical network models. The analysis shows that there strongly exist a scale-free and a small-world properties in the Usenet network. We also examine the community structure of this network and show that a small number of Usenet news servers that are highly contributive for article feeds forms the largest community and other servers tend to be categorized by their geographical locations