On Evolving Network Model and Topological Properties of Instant Messaging Systems

We propose and study an evolving network model for instant messaging system (IMS) with local-world preferential connections and acquaintance introduction mechanisms, which exist in many physical complex networks especially in IMS evolving network. We put forward the algorithms to generate IMS evolving network model and through simulation results we talk about the topological properties of the IMS evolving network. First of all, degree distribution, clustering coefficient along with average path length are simulated and then the community structure of the model is analyzed. We can draw the conclusion that the degree distribution of IMS evolving network doesnpsilat obey power-law distribution, and this network has a short average path length and a high clustering coefficient. In a word, the simulation result shows that the IMS evolving network is a complex network possessing properties of small-world and clear community structure, but doesnpsilat have scale-free property.