Research On Reliability Optimization Of Post-earthquake Emergency Logistics Network Under Facility Disruption Scenarios

The Problem of Facility Location in Emergency Logistics after Earthquake is a key link in the optimization of emergency logistics system.The location of facilities directly affects the logistics system's service mode,operating efficiency and other aspects.Due to the frequent occurrence of secondary disasters such as aftershocks and debris flows,the facilities established are likely to be interrupted by the secondary disasters,which will paralyze the entire emergency logistics network.Therefore,the purpose of this paper is to consider the facility's disruption risk in the decision-making stage of facility location and build a reliable post-earthquake emergency logistics network so that the system can run well in the face of various outage scenarios.The content of this paper is mainly divided into the following parts:(1)On the bases of analyzing the characteristics of demand,supply,emergency logistics network optimization goal and topological structure of the post-earthquake,the features of the emergency logistics network after the earthquake is concluded to be unreliability,uncertainty,dynamics,and stages.Based on the analysis of the features of emergency logistics network after earthquake,we divided the emergency allocation process after the earthquake into two phases: the early phase of emergency rescue(1-7 days after the earthquake)and the later phase of emergency rescue(7-14 days after the earthquake).(2)According to the different characteristics of the two stages of the actual rescue process,using robust optimization method and taking into account the facility outage scenarios,we construct a location-allocation model and a location-inventory model with multiple types of materials,multiple candidate facilities,and multiple disaster demand points from the emergency distribution center to the disaster demand site.(3)According to the different characteristics of the two stage model,the corresponding genetic algorithm is designed to solve the model.Aiming at the multi-objective optimization problem in thelater stage of emergency rescue,this paper designs an improved non-dominated sorting genetic algorithm,which can get the Pareto optimal solution set.(4)Taking the Wenchuan earthquake as an example,the operational results of the post-earthquake emergency logistics network established considering the facility outage scenarios are compared with the operating results of the post-earthquake emergency logistics network established without considering the facility outage scenarios.At the same time,the operational results of the emergency logistics network established considering the facility outage scenario and the emergency logistics network established without considering the facility outage scenario when no facility disrupted are compared with the operating results in the event of facility outages.Then verify the effectiveness of the models and algorithms of the two stages.Research shows that,compared with the post-earthquake emergency logistics network established without consideration of the facility outage scenario,the results considering the facility outage scenario has higher reliability in two aspects;Firstly,the gap between the post-earthquake emergency logistics network established considering the facility outage scenario and the emergency logistics network established without considering the facility outage scenario is not significant.Secondly,the post-earthquake emergency logistics network established considering the facility outage scenario will not significantly deviate from the expected target even if some of the facilities in the system are interrupted,while the post-earthquake emergency logistics network established without considering the facility disruption scenario will undergo drastic changes in the operational results.Therefore,building a reliable post-earthquake emergency logistics network can better cope with the risks and consequences caused by facilities interruption,enabling the whole system to run well even if some facilities in the system break down.This not only has theoretical research value,but also provides auxiliary decision support for the emergency rescue department after the earthquake.