Study On Post-earthquake Emergency Logistics Path Planning Based On Multi-objective Optimization

Natural disasters such as earthquakes and typhoons have occurred from time to time around the world,posing great threats to people's lives and property.China's land area is large,and these natural disasters are also common in all parts of the country,especially some very serious disasters,which will cause large-scale casualties and huge economic losses.Therefore,the government needs to respond quickly after the disaster and organize effective emergency rescue operations,and strive to minimize the damage caused by disasters in a short period of time.However,after a disaster,it often causes complicated conditions such as reducing road capacity or difficult to pass.Even in some areas,secondary disasters will occur.Therefore,decision makers need to consider the time requirements of each affected areas,and whether these areas pose a security threat to rescuers and vehicles according to the actual situation,also need to make decisions quickly and give reasonable emergency vehicle distribution plans,in order to achieve the ultimate goal of mitigating the impact of disasters.This paper compared emergency logistics with general logistics firstly,and analyzed the characteristics of emergency logistics,then conducted research on the strong time constraints and weak economic nature to emergency logistics,afterwards,proceeded to the core of the paper from the aspect of emergency logistics path optimization.On this basis,this paper took the earthquake disaster as the background and established two different models,based on the characteristics of emergency logistics and the traditional logistics vehicle routing problems,using the relevant knowledge of operations research,considering the troop vehicles transporting troops and volunteers to the affected areas.Model 1 mainly considered factors that might cause changes in vehicle speed after the earthquake,such as earthquake occurrence time,road type,driving safety and so on,then corrected the vehicle speed.And,according to the structure of one rescue center serving multiple disaster affected areas,established the optimization model with the minimum total travel time of rescue vehicles.Model 2 considered that secondary disasters that might occur after the earthquake had the least threat to rescuers'(troops,volunteers,and emergency rescue forces)personal safety while the vehicle was moving forward.This point was mainly from the perspective ofpath risk,and proposed to select the path where the possibility of secondary disasters was as small as possible to transport rescuers.Then according to the ArcGIS information model,the risk of each road segment was quantitatively analyzed,and finally the optimization model with the minimum path risk was established.Since the dimensions of the two objective functions were different and it was difficult to convert one of the targets into the constraint of another target,this paper adopted NSGA-? that had obvious advantages in solving multi-objective problems to solve the established model and used MATLAB R2016 a to program to get the Pareto optimal solution set of the model.Finally,the model established in this paper was applied to the actual case of the post-earthquake road network in Jiuzhaigou earthquake in 2017,and the final optimization scheme was obtained.The feasibility and effectiveness of the model and algorithm designed in this paper were verified.