Models And Algorithm For Post-Earthquake Allocation And Distribution Of Relief Materials

As one of the main disasters in China, earthquake causes huge casualties and property losses. Collapsed houses, paralysed infrastructure, severe property damage and tragic death of thousands of people were led by the earthquakes happened in Wenchuan in 2008 and Yushu in 2010. Admittedly, the timely forecast of earthquake is essential. Yet, efficient approaches should be implemented since earthquakes inevitably result to disruptive consequences. Once an earthquake happens, a large amount of emergent needs of kinds of supplies must be met. So, combined with the actual situation of the rescue activity, how to optimize the distribution and dispatching system efficiently and scientifically, strenthen the support and response capability of the whole system and improve the distribution and dispatching satisfation and timeliness are the key points to keep the whole emergency logistics system stable and reliable.In the existing researches on emergency logistics system, most studies confined to a single stage of facilities or the single transport. However, multi-echelon facilities and multi-modal transportation are cooperated with each other in reality and every transport has its own characteristics. Therefore, it’s necessary to study the distribution and dispatching problems when there are multi-echelon facilities and multi-modal transportation. In the background of the distribution of the emergency supplies and the dispatching of the transportation tools in the rescue stage, the paper discusses the results of the relevant literature and on the basis of analyzing the distribution and dispatching system, the distribution and dispatching problems are deeply investigated.Firstly, the paper studies the bilevel model and its algorithm of the distribution problem under the condition of incomplete information at the initial phase of the rescue activty. After the comprehensive thought of the features of the integrated optimization of the emergency system and the difference between the emergency logistics and the normal logistics, considering the information of the supply needs and the transportation that can’t be obtained timely, the multi-echelon facilities, multi-modal transpotation, incomplete information, timeliness of the rescue activity, fairness of the distribution of the relief, a bilevel opitimization model with subordinate hierarchical relationship is formulated. According to the characteristics of the model, an improved genetic algorithm is proposed and a numerical example validates the effectiveness of the model and the algorithm.Secondly, the paper studies a dynamic, multi-objective model when the information can be easily got as the rescue goes on. With the continued efforts in rescue, dicision makers are able to know the new information of demand and traffic condition and must make dynamic new dicisions when the new information is updated. Considering the multi-echelon facilities, multi-modal transportation and time limitation, a dynamic, multi-objective model is formulated and a multi-objective, improved genetic algorithm is proposed. A numerical example validates the effectiveness of the model and the algorithm.