Abstract: In recent years, major emergencies have occurred frequently all over the world. The scheduling of emergency medical supplies is the key link of emergency medical supplies support. There are some issues of the single-cycle multi-transportation mode emergency medical supplies scheduling model, such that the transportation network is not appropriate, constraints of transportation modes are not considered comprehensively, or dynamic changes of supply and demand are not considered, resulting in local redundancy and unfairness of scheduling.
Firstly, the multi-period dynamic scheduling model of emergency medical supplies under emergencies is established. According to the response characteristics of emergency medical supplies after the outbreak of emergencies, this thesis adopts the three-level transportation network, from supply point to distribution center and to demand point. It uses a variety of transport tools to transport jointly, considering capacity constraints for trucks and departure schedule constraints for trains and aircraft. It establishes a dynamic demand urgency indicator for demand points and calculate a dynamic demand urgency of demand points to correct their satisfaction rates. By dividing the period and aiming at the shortest scheduling time and the maximum sum of the satisfaction rate of the affected people, a model of emergency medical supplies is constructed with multi-supply point, multi-distribution center, multi-demand point and multi-period dynamic scheduling.
Secondly, an algorithm based on non-dominated sorting genetic algorithm-II (NSGA-II) is designed for solving the dynamic scheduling model of emergency medical supplies. For individual coding, the combination of string coding and natural number coding can intuitively show the entire scheduling scheme. For non-dominated sorting, it is difficult to consider all constraints in individual coding due to a large number of model constraints. The traditional non-dominated sorting method is improved, and the individuals who meet the demand of the constraints and those who do not are hierarchically divided according to the magnitude of individuals exceeding the constraints.
Finally, a case of multi-period dynamic scheduling of emergency medical supplies is studied. The designed case is solved by the NSGA-II algorithm. The results show that at the end of scheduling response of emergency medical supplies, the higher the demand urgency of demand point is, the more its satisfaction rate exceeds the minimum satisfaction one. With an increase in the satisfaction rate of demand point in the whole scheduling process, the final demand is satisfied, which verifies the validity and rationality of the model. At the same time, the genetic algorithm (GA) is used to compared with the NSGA-II algorithm. The results show that the scheduling scheme set solved by the NSGA-II algorithm dominates the scheduling scheme by the GA algorithm, reflecting the effectiveness and advantage of the NSGA-II algorithm.
The conclusions show that the model built in this paper can consider the constraints of different transportation modes, and materialize the idea that the higher the urgency of the demand point, the greater the value of its satisfaction rate exceeding its minimum satisfaction rate, which ensures the fairness of the distribution of emergency medical materials.

Key words: emergency medical supplies, dynamic scheduling, demand urgency, NSGA-Ⅱ

摘要： 在新冠疫情等重大突发公共卫生事件下,如何运用多种运输方式动态、高效、公平地适时、公平地调拨应急医疗物资,对于保障疫区人员的生命安全尤为重要。针对单周期、多运输方式应急医疗物资调度模型中的运输网络选择不恰当、运输方式约束考虑不全面、未考虑动态供需变化导致物资调度局部冗余、公平性无法保障等问题,本文基于多供应点、多分配中心、多需求点的三级运输网络,考虑汽车运力以及火车发车、飞机航班约束,通过划分周期,以调度时间最短、需求点应急物资满足率之和最大为目标,构建应急医疗物资多周期动态调度模型;建立需求紧急度指标,计算需求点紧急度对其满足率进行校正,以保障应急医疗物资分配的公平性。针对实际案例,采用NSGA-Ⅱ算法求解模型,并与传统GA算法对比,验证了算法和模型的有效性。研究结果表明:本文所建模型能考虑不同运输方式约束,实现了需求点的紧急度越高,其满足率超过其最低满足率的值越大,确保了应急医疗物资分配的公平性。

关键词: 应急医疗物资, 动态调度, 需求紧急度, NSGA-Ⅱ