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为了完善高速公路的紧急救援系统,降低事故后果,需要设立合适的急救站,而首要解决的问题是急救站的选址。考虑了事故发生和事故处理时间不确定情况下的紧急救援站选址问题。假设网络各点事故产生是一个泊松过程,单个设施对事故处理的时间符合负指数分布,通过选址决策,使得覆盖的事故数量以及对事故的响应时间都较满意,响应时间为急救站距离事发地点的行驶时间。以最大覆盖模型为基础,结合排队理论,建立混合整数双目标模型,决策目标为服务数量最大化和服务时间最小。由于模型是NP困难问题,采用带精英策略的非支配排序遗传算法NSGA-Ⅱ求解,求得Pareto最优解。最后给出了算例。算例结果验证了模型的合理性和算法的有效性。
In order to perfect the emergency rescue system of the expressway and reduce the consequences of the accident, a suitable first aid station needs to be set up, and the first problem to be solved is the location of the first aid station. Taking into account the accident and accident handling time uncertain emergency rescue station site selection. It is assumed that the accident at each point in the network is a Poisson process. The time taken by a single facility to deal with the accident is in accordance with the negative exponential distribution. Through the site selection decision, the number of accidents covered and the number of accidents covered are satisfactory. The response time is the distance Driving time at the place of the accident. Based on the maximal coverage model and combined with queuing theory, a two-objective model of mixed integer is established. The objective of the decision-making is to maximize the number of services and minimize the service time. Because the model is a NP-hard problem, the non-dominated ranking genetic algorithm with elitist strategy NSGA-II is used to solve the Pareto optimal solution. Finally, an example is given. The result of the example verifies the rationality of the model and the validity of the algorithm.