| At present, cities in china, especially mid-minor cities have good economic development while bad emergency management. But often after the emergent accidents occurred, information can't be received in time,resource can't be fully made use of. Because of this, the effect of the emergency management can't thoroughly realized. So a really fast, efficient, good organized, have right and ability for the accidents system of emergency management should be built in our citiesThe thesis demonstrated the modeling based on Petri-net theory at first. described the process of Petri-net applied in the mid-minor city emergency management system, Started with the work flow of emergency management system, established the Petri-net points system model, defined the places, changes and token mentioned by Petri-net theory. Modeled the above emergency work flow. equivalent simplified the stochastic Petri-net and proved the rationality and feasibility of model by Markov chain. Then used Petri-net optimization algorithm method to calculate the concrete valuations for the model from the performance of time efficiency and resource allocation, so as to solved the model's advantage in the emergency management system.The thesis took the flows mentioned as a guard and used the emergency management of 11.24 disaster in Yan'tai sea as the example to established a reasonable stochastic Petri-net model, Then calculated with the simplified Petri-net optimal path. In the case of Petri-net modified, the minimum execution time selected by the optimal path was the 0.142 times of the common execution time. While it's the 0.314 times of the ordinary modal under the condition of effective information feedback and expert opinion. The effective time calculated in this thesis was less than 2.19h, compared with 7h by the ordinary modal, it improved the efficiency of emergency system significantly, and proved the rationality and enormous advantage of this model in emergency efficiency meanwhile. |
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