Research On Emergency Material Distribution With Uncertain Service Request At Demand Point

The distribution of emergency materials after sudden disasters has important theoretical significance and practical value.The existing research is generally in the demand point service request to determine the case of building a vehicle routing model,well-designed algorithm,in practice,however,the requirement point service request may be uncertain;research on material distribution with uncertain service demand at demand point,it’s usually for general supplies,can not meet the distribution needs of emergency supplies;and the study of emergency supplies,the goal is usually to minimize the total time and the total distribution cost,no consideration is given to the actual situation where each demand point has a delivery time requirement.In response to the lack of existing research,in this paper,we consider the case where the service requests are made sequentially and there is a delivery time requirement,total distribution cost（total travel cost+total delay loss cost）should be as small as possible,the theory and method of adopting online problem and competitive strategy,this paper studies the online distribution of emergency materials from two perspectives:the online distribution of emergency materials which can not be predicted by the service request of demand point,and the online distribution of emergency materials with limited forecast of demand point service request,design on-line distribution strategy of emergency materials,list different situations,sum up the competition ratio,verify the implementation effect.The main innovative achievements of this paper are as follows.Design of on-line distribution strategy for emergency materials with unpredictable service request at Demand Point.Emergency material distribution problem with uncertain service request at demand point,consider the situation that the service request of the delivery vehicle to each demand point can not be predicted and each demand point has a delivery time requirement,the total distribution cost（total travel cost+total delay loss cost）should be as small as possible,an on-line route selection model for emergency material distribution is established,which can not be predicted by demand point service request,design comparison strategy,this paper analyzes the two situations of the distribution vehicle:the demand point distribution which sends the service request first and the demand point distribution which sends the service request last after each choice,it is proved that the competitive ratio of the comparison strategy is 2+m₂/m₁+（m₁+m₂）/m₁·（α/β）（α<β）.Finally,an example is given to verify the effectiveness of the strategy.Design of on-line distribution strategy for emergency materials with limited forecast of service request at Demand Point.Emergency material distribution problem with uncertain service request at demand point,consider that the service request issued by the delivery vehicle to each demand point is limited and each demand point has a delivery time requirement,that is,the delivery vehicle can predict how long the next demand point will send a service request when it receives a service request from a demand point,a situation in which the location and delivery time of a service request can be known only when the next point of demand makes a service request,the total distribution cost（total travel cost+total delay loss cost）should be as small as possible,an on-line route selection model for emergency materials distribution is established based on limited forecast of service requests at demand points,design delay service strategy,according to the number of service demand points and the shortest path to the demand points,four cases are given and analyzed,it is proved that the competitive ratio of the delay service strategy is（?）.Finally,an example is given to verify the effectiveness of the strategy.