Research On Post-Earthquake Emergency Material Cooperative Dispatching Considering Lateral Transshipment Policies

In recent years,earthquakes have occurred frequently,such as the Wenchuan earthquake in May 2018,the Yushu earthquake in April 2010 and the Lushan earthquake in April 2013,which all have seriously affected economic development and social stability.In order to save lives of people and reduce losses caused by earthquake disasters,emergency materials must be dispatched to emergency logistics centers in shortest time,so that they can be delivered to the disaster areas on time.However,there is much uncertainty of the happen of earthquake disasters and their effects.When the demand for emergency materials is abrupt to change due to the occurrence of post-earthquake disasters,it usually is difficult to complete the out-of-stock replenishment in a short time because of the long replenishment time,while at this time the rest of the emergency logistics centers may still have surplus materials,causing that the emergency materials cannot be even distributed and be fully utilized.For this kind of emergency materials dispatching problem,it is important to reduce the total cost of emergency materials dispatching system,improve the satisfaction of materials in the disaster areas and optimize the inventory of emergency logistics center by effectively lateral translating between the emergency logistics centers to feed the shortage of goods.Below are the main research contents of this thesis:(1)Contrary to the characteristics and shortcomings of the traditional vertical transshipment mode for emergency materials dispatching,a post-earthquake emergency material dispatching transport network considering lateral transshipment is proposed based on the analysis of the characteristics of emergency materials dispatching.Moreover the complete and the partial transshipment strategy are designed to correspondingly fulfill the distinct scheduling characteristics requests of different emergency materials with single-cycle and multi-cycle backgrounds.(2)For the emergency materials dispatching problem of post-earthquake work materials and special materials,a complete lateral transshipment strategy is adopted in order to handle the uneven distribution and sudden change in demand of single-cycle emergency materials.A single-cycle complete lateral transshipmentpost-earthquake emergency materials dispatching model is established,with multiple objectives of the shortest transit time,the lowest total system cost and the highest material satisfaction rate.The NSGA-?(Non-Dominated Sorting Genetic Algorithm-?)multi-objective optimization algorithm is designed to solve the problem,and the Lushan earthquake disaster is taken as an example to verify the validity of the model and algorithm.The research results show that after the earthquake disaster,the lateral transshipment of emergency materials between emergency logistics centers can effectively improve the material satisfaction of each emergency logistics center and reduce the total cost of the emergency materials dispatching system.(3)For the emergency materials dispatching problem of the daily life materials for the victims after the earthquake,multi-cycle dispatching is required to ensure the daily use of the victims in each demand cycle.To cope with the waste of materials due to the surplus in emergency logistics centers and sudden changes in demand caused by post-earthquake disasters,a partial lateral transshipment strategy is adopted.A multi-cycle partial lateral transshipment post-earthquake emergency materials dispatching model is established,with multiple objectives of the shortest transit time,the lowest system cost and the highest material satisfaction rate,and an algorithm is designed to solve the problem under the validation of Lushan earthquake as an example.The results show that considering the lateral transshipment in the emergency material dispatching system can effectively reduce the inventory of the emergency logistics centers and the total cost of the emergency materials dispatching system in the multi-cycle.The research results can effectively realize the rapid response for the dispatching of emergency materials after earthquakes,avoiding resources losses and low material satisfaction rate due to the uneven distribution and sudden change in demand of emergency materials,which holds much significance to reduce the total cost of emergency materials dispatching system and the inventory amount of emergency logistics centers,and improve the emergency material satisfaction rate.