| Natural disasters often occur in most regions of China,causing casualties and property losses,affecting the stable and rapid development of China’s economy.Moreover,in recent years,China is in a period of high incidence of public health emergencies.In the future,China will face the test of public health emergencies.Therefore,in order to reduce casualties and property losses,emergency logistics has received huge financial support and policy encouragement from the government.In order to improve the emergency logistics system,how to improve the efficiency of emergency supplies distribution and reduce the cost of emergency supplies distribution in emergency scenarios is an urgent problem to be solved.Based on this,according to different emergency scenarios,the timeliness requirements of demand delivery are also different.This thesis proposes to use trucks-drones delivery mode,and divides the research issues into two categories.In the process of emergency rescue,in view of the characteristics of strong timeliness of emergency supplies distribution,the optimization research of truck-drones distribution for real-time emergency needs is proposed.during the postdisaster transition period work,in view of the weak timeliness of emergency supplies distribution,which can be delivered within the corresponding soft time window,this thesis proposes the research on optimization of truck-drones distribution with soft time window.The specific contents and research conclusions are as follows:(1)Research on the optimization of truck-drones delivery in emergency rescue.Analyze the characteristics of the truck-drones delivery problem,considering the uncertainty of emergency material demand and real-time scheduling in this problem,and use online thinking to study this problem.The lower bound of this problem is proved,and the online algorithm that calls the offline optimal algorithm is designed on the general network,and the upper bound of the competition ratio of the online algorithm is analyzed.A mathematical model was established with the goal of minimizing the total service time for the offline delivery problem of truck-drones in emergency rescue,and a three-stage offline heuristic algorithm was designed to solve and verify the effectiveness of the algorithm.Finally,the simulation analysis proves that the online algorithm has better application effect in the real scene,and has certain reference value for the truck-drones distribution problem in the emergency rescue in the real life.(2)Research on optimization of truck-drones delivery during the postdisaster transition period.Considering that after the disaster situation tends to be stable,the distribution of living materials in the disaster-affected areas during the postdisaster transition period work has a low time urgency,and that in real life,there are often early arrival and delayed arrival of materials,so it is worth studying to design the scheme of truck-drones distribution with soft time window to minimize the total distribution cost.A mathematical model aiming at minimizing the total service cost is established,and an improved large neighborhood search algorithm is designed to solve and verify the effectiveness of the algorithm.Finally,the simulation analysis shows that the increase of demand intensity,time window interval and drones flight radius can reduce the total distribution cost.The truck-drones with soft time window distribution mode is proposed,which can not only solve the problem of high logistics distribution cost in emergency situations,but also expand the application scenarios of this mode. |
