Research On Location-routing Problem Of Emergency Logistics System In Uncertain Environment

In recent years,public health emergencies and natural disasters have occurred frequently,which has greatly threatened the safety of people’s lives and property.In this context,the low timeliness and low economy of emergency materials distribution are the main problems.Therefore,if we want to improve the timeliness and economy of emergency materials distribution and reduce the losses caused by public emergencies and natural disasters to people’s lives and property,we need scientific and effective system planning research,so it is very important to optimize the location-routing problem of the emergency logistics system.In order to improve the timeliness and economy of emergency materials distribution,this paper studies the emergency logistics system after public health emergencies and natural disasters,and optimizes the location-routing problem of emergency logistics system,so as to provide a certain reference value for the practical work of emergency materials distribution.This paper optimizes the location-routing problem of emergency logistics system for different backgrounds.Firstly,for the emergency logistics system after public health emergencies,this paper establishes an uncertain chance-constrained optimization model trending to minimize the total cost.Considering the actual situation,we assume that the emergency supplies must arrive before the deadline of the demand point and the capacities of the vehicles and the candidate distribution centers are finite.And the material demand is considered to be uncertain,but the transportation time of the two nodes is determined.And in order to save costs,it is assumed that the vehicles will stop at the opened center after completing its own distribution task.Secondly,for the location-routing problem of emergency logistics system after natural disasters,this paper establishes an uncertain chance-constrained optimization model with biobject of shortest total time and the smallest total cost.Considering the actual situation,we assume that the emergency supplies must arrive before the deadline of the demand point and the capacities of the vehicles and the candidate distribution centers are finite.And the material demand and the transportation time of the two nodes are considered to be uncertain.And in order to save costs,it is assumed that the vehicles will stop at the opened center after completing its own distribution task.Then,genetic algorithm is applied to solve the above models by Matlab programming.In the single-objective emergency logistics system location-routing problem optimization model after a public health emergency,the idea of a penalty function is used to deal with certain constraints.In the two-objective emergency logistics system location-routing problem optimization model after natural disasters,the idea of a penalty function is also used to deal with certain constraints,while the weighted method is used to deal with both targets.In the test of numerical examples,satisfactory optimization results are obtained in a short time,which illustrates the usability of the model and the algorithm.