Research On Location Of Urban Emergency Logistics Centers Under Major Earthquake Disasters

With the rapid development of economy and society,the level of urbanization in our country is continuously improving,at the same time,China's frequent earthquake disasters pose a serious threat to urban development and regional prosperity.Major earthquake disasters have the characteristics of rapid explosion,difficult forecasting and large impact,as a political,economic,cultural and transportation center in a certain area,cities have many characteristics such as large population,high density of buildings,important functions,concentrated resources and complex systems,therefore,the major earthquake disasters that have broken out in the cities are characterized by a wide range of affected people,heavy losses,secondary disasters are more frequent and have stronger consecutive,lasting impact of disasters,disaster evolution is complicated and other features,which make disaster relief more difficult and the need for emergency logistics more urgent,in order to effectively deal with major earthquake disasters,it is of great significance to plan and build an urban emergency logistics center in advance and do well in material reserves.Based on the basic characteristics of major urban earthquake disasters,characteristics of emergency logistics and other basic theories,this paper analyzes the characteristics of emergency logistics center of the city,elaborates the thinking and role of the construction of urban emergency logistics centers under major earthquakes,further,analyzes the principle,steps and influencing factors of its site selection,based on the above theories,this paper establishes a model for the location selection of urban emergency logistics centers under major earthquakes.The model has the following characteristics: 1.emphasis on covering all demand points and timeliness,constraining the response time of each demand point with time window to ensure that all demand points can obtain timely service;2.due to the complexity of the urban system and the differences in each region,the response time constraint and demand of each demand point should be different due to factors such as the number of people,the importance of the area and the risk of disasters;3.considering the actual conditions of finance,land and other conditions in the city,emphasize the maximum construction volume and resource reserve limit of the urban emergency logistics center;4.with the goal of minimizing the total cost,under the premise of ensuring timeliness and fairness,save investment and achieve social and economic benefits by rationally allocating resources.Because this model is NP-hard problem,in order to solve the model and obtain the location selection scheme,this paper designs an improved genetic algorithm and uses computer software MATLAB 2012 a to program.In the design of genetic algorithms,select the appropriate coding method,fitness function,genetic operation,penalty function,etc,and analyze the effect of the Popsize,Maxgen and Pm on the calculation result,the operation time and the convergence algebra,so as to determine the parameter values of the algorithm and make it perform well.The example shows that the genetic algorithm designed in this paper can effectively solve the location model and explain the rationality of the model.it will provide a feasible and easy-to-operate method for the emergency management department to select sites for future urban emergency logistics centers.