System dynamics model of public emergencies evolution

Combining with the theory of chaos and dissipative structure, this paper analyzed the development and evolution process to public emergencies from the point of dissipative structure. According to the three dimensions, disaster hardness, degree of stricken and management level, equation of state was built here. This paper solved the latent root, analyzed the characteristic of event system balance point and the interaction of the three dimensions, and discussed the development and evolution of public emergencies. Based on the system dynamics model, decision makers can understand deeply the public emergencies from the point of internal characteristic, therefore, and improve the capability to response.