Research On Emergency Logistics Facilities Location And Vehicle Routing Problemfor Multiple Emergency Scenarios

With the rapid,continuous and stable development of national economy,the living standards of the people are changing rapidly.At the same time,due to national natural geographical environment and the adverse factors in economic development,all kinds of emergencies happen frequently,which bring great influence to people's life,social stability and economic development.Although the current level of science and technology has been greatly improved than before,good measures have been taken in the prevention and handling of all kinds of emergencies.However,these emergencies can not be avoided any recurrence.To this end,we can establish good emergency logistics system to minimize the loss caused by emergencies,in which we choose a number of alternative storage centers to open and store a certain amount of emergency relief supplies before the occurrence of emergencies,and use vehicles to distribute the emergency relief supplies from the storage centers to the affected area.It is beneficial to improve the stability,timeliness and reliability of the whole emergency management system by making scientific decisions of selecting the location of emergency logistics facilities and vehicle routing.In this paper,the decision of the location of the alternative storage centers in the preparation stage of emergency management and the decision of vehicle routing in different emergency scenarios in the reaction stage of emergency management are integrated,and a two stage model is constructed to solve the problem,in which the first stage is to minimize the opening cost of the alternative storage centers in location model and the second phase is a vehicle routing model which aims to minimize the total transportation time of an emergency scenario.Based on the idea of the worst case of robust optimization and stochastic optimization,the paper transformed the two stage model into the single worst scenario model and a stochastic optimization model respectively,and LINGO software is used to solve a small scale case,the results show that the solution of the worst scenario model based on robust optimization is more stable than the solution of the stochastic optimization model.At the same time,this paper designed a Hybrid Elitist Genetic Algorithm,and take numerical simulation calculations on small scale,medium scale and large scale case.The solution of small scale case shows that this algorithm not only has the same precision as precise algorithm in solving small problems,but also a significantly compute speed,the solutions of medium scale and large scale numerical simulation calculation show that the algorithm is effective and stable in solving large scale problems,which can provide theoretical and technical guidance for emergency management departments to make relevant decisions,and has both important theoretical and practical significance.