Research On Model And Algorithm Of Location-Routing Problem(LRP) For Emergency Logistics System In Post-earthquake

The frequent earthquake disasters caused huge casualties and property losses in recent years. For example, Wenchuan earthquake, Yushu earthquake and Yaan earthquake. In order to save the lives of the people in the disaster areas, and to reduce the damage caused by the earthquake disaster as far as possible, emergency supplies must be supplied to the disaster area in the shortest possible time after the earthquake, especially the rescue equipment, medical equipment and medicine in the early post-earthquake. Earthquake relief requires many varieties, large quantities of emergency supplies. The emergency of earthquake disaster, the destruction and the time urgency of emergency material supply brought the huge challenge to the emergency logistics system in post-earthquake. According to the feedback information of the actual relief distribution of Wenchuan earthquake disaster, scholars generally believe that the key of emergency suppliy is the location allocation problem(LAP) of emergency facilities and vehicle routing problem(VRP). Moreover, there is interdependence and mutual influence between LAP and VRP. The overall design and optimization of LAP and VRP must be carried out, which is to study the location-routing problem(LRP) of emergency ogistics system in post-earthquake.There are many uncertain factors in the process of emergency supply. For example, strong aftershocks lead the original smooth road system to partial paralysis, sharp increase in relief demand of partial demand points caused by sudden large scale plague outbreak in the disaster area, vehicle damage in the service process. Such events are called interuption events. At this point, if the decision makers carry out an emergency supply in accordance with the original plan which made before the incident, partial demand point can not be served. So, to effectively deal with the interruption, the emergency supply plan should be adjusted according to the specific circumstances of the interruption, the goal is to minimize the perturbation of emergency logistics system, and to effectively ensure the supply of emergency materials.In this paper, the LRP for the emergency logistics system in post-earthquake are studied. This paper focuses on the features of emergency supply after the earthquake with the real relief distribution data of Wenchuan earthquake, Yushu earthquake and Yaan earthquake. The multi-objective LRP models with different real situations, disruption management model of LRP for emergency logistics system in post-earthquake, and corresponding solving algorithms are desigened to solve the proposed problem. These algorithms are tested with the distribution data of the Wenchuan earthquake emergency relief. This paper includes the following contents:(1) Analysis on the features of emergency relief delivery in post-earthquake. This paper pointed out that the earthquake disaster has the characteristics of sudden, huge damage, time continuity and periodicity. The demand of emergency relief is complex, hierarchical and dynamic. Emergency supply has the features of time urgency, the quantity huge and the emergency logistics network complexity. LRP of emergency logistics system in post earthquake post earthquake has the features of time priority, environmental complexity, supply mode diversity and dynamics.(2) Research on a new LRP of emergency supply in post-earthquake. A new LRP of material distribution in post-earthquake is considered. It is assumed that there are n nodes, and m nodes is selected from the n nodes to be emergency logistics centers without capacity constraints, i.e. NM ?. A LRP model with multiple objectives is formulated by considering the characteristics of limited facility transportation capacity, the location and the terrain of the demand point, stochastic vehicle driving time, uncertain demand and time urgency.. The goal of the LRP model is to minimize the total delivery time and the total costs in delivering relief materials. A hybrid Immune genetic algorithm is proposed to solve the proposed problem.Finally,the feasibility and validity of the proposed approaches are demonstrated by the experimental results.(3) Research on fuzzy dynamic LRP for multimodal relief delivery in post-earthquake. A multi-period programming model for the fuzzy dynamic LRP was developed by considering the following characteristics: fuzzy demand of relief materials, time window constraints, dynamic rehabilitation of affected road networks, stochastic vehicle travel time, segmentation strategy employed for the node with great demand, multimodal relief delivery, and split deliveries. The goal is to minimize the total time and total cost in relief delivery. A hybrid heuristic algorithm was proposed to solve the model. Finally, the feasibility and validity of the proposed approaches were demonstrated by a numerical example.(4) Research on LRP model and algorithm of multimodal distribution of emergency materials after earthquake in the perspective of fairness. By considering the urgent window constraints, the partial road damage and dynamic recovery in emergency logistics network, the stochastic vehicle time, the multi-variety relief materials and multimodal deliveries, the fairness theory is introduced into the emergency material distribution after the earthquake, a multi-objective model for the LRP in post-earthquake multimodal fair delivery of multi-variety relief materials was developed, and the goal is to minimize the total time in delivering relief materials and the waiting time of the demand point. A hybrid heuristic algorithm was proposed to solve the model.Finally,the feasibility and validity of the model and algorithm was demonstrated by a numerical example derived from Wenchuan earthquake.(5) Research on disruption management of LRP for emergency logistics system in post-earthquake. The disruptions in the process of emergency material distribution are studied by considering the fuzzy demand of relief materials, time window constraints, damaged networks, and split deliveries. A LRP model is constructed to minimize the total time in relief delivery. Combining the behavioral perception, this paper analyzes the effects of disruption on the demand point, decision maker and logistics worker. Based on disruption management theory, a multi-objective lexicographic model of disruption management is formulated. The goal is to minimize the system disruption. The disruption management strategy and a hybrid heuristic algorithm are proposed to solve the model. Finally, the test results show that the proposed approaches is more practical and effective than the global rescheduling method and the local rescheduling method.The results of this study can effectively Guarantee emergency supplies, avoid the imbalance between supply and demand of emergency supplies, realize rapid response of emergency supply after earthquake, reduce the total cost of emergency logistics system, and reduce the loss and damage caused by earthquake disaster. So, this paper has important theoretical and practical significance. This study complements and improves the theory and optimization method of emergency logistics management. It provides a new idea and direction for the research of emergency logistics, and provides research guideline for colleagues. At the application level, it can provide a reference for the emergency management decision-making department.