Abstract:

The unexpected disaster refers to a disaster that is difficult to prevent and has sudden and highly uncertain characteristics. After the outbreak of unexpected disasters， there will be a shortage of materials. Efficient distribution of emergency materials is the key to ensuring people’s life safety， maintaining their living needs and reducing disaster losses. In the complex and dynamic environment after the disaster， the demand for emergency materials at each demand point is highly uncertain， and the emergency management department cannot predict the demand in advance.The route selection problem for emergency materials distribution is proposed in this paper. The service requests with service time requirements are considered to be sent from each demand point in turn， and the objective is to make the total travel cost add total delay cost as small as possible. An on-line route selection model with unpredictable service requests is established. A comparison strategy is designed based on the comparison between the cost from the current point of the distribution vehicle to the first-to-go demand point and the cost from the current point of the distribution vehicle to the demand point with new service request. The competitive performance of the comparison strategy is discussed in two different cases， and the competition ratio of the comparison strategy is proved.Finally， the implementation of the comparison strategy is validation by a practical case based on the real road network in Jianghan district of Wuhan city. The ratio of the total cost of the online strategy to the optimal cost of the offline problem is 1.9， which shows that the implementation of the strategy is good. A reliable research idea for route selection for emergency materials distribution with unpredictable service requests of demand points is provided. Future research can investigate how to design a better online strategy.

Key words: unpredictable, route selection for distribution, online strategy