Abstract: Information propagation model in the micro-blog is the basis of many researches, including analyzing user behavior, discovering the ways of spreading, confirming leaders and detecting public opinion hot spots. At present, a1though there has been extensive research on information propagation models which from different angles, these models often lack the intuitionistic description for the information dissemination process. Based on the structure and characteristics of Petri nets, a simple and intuitive description model is presented for the process of information dissemination in micro-blog network. This model first describes the objects in the process of dynamic information dissemination in micro-blog network.According to the micro-blog network information dissemination process, a simple and intuitive description model based on Petri nets is proposed. This paper uses the theory of Petri nets to explain and define the basic objects of message propagation based on the user structure of micro-blog network, and more directly shows the user behavior, including reposting, commenting, replying and so on. On this basis, in the combination with colored Petri nets and timed Petri nets, the feature of Petri nets is used to present the message transmission path from the perspective of Petri nets system. the dynamic property and propagation conditions of micro-blog network are also studied, so that the information propagation model can simulate the message transmission more actually. Finally, the case study of the information diffusion model is carriedon and real data on Sina micro-blog are used to do experiments and analysis, which demonstrate the feasibility and availability of the model and provide supports for public opinion analysis and user behavior research. Meanwhile, this model can further provide a new idea for describing user behavior in message propagation system of other social networks.

Key words: Petri nets, online user behavior, social network, dynamic information propagation