中文摘要：

在竞争环境下,时间效率是构建服务系统需要考虑的重要因素.基于M/M/c排队系统,考虑服务系统期望旅行时间最小化与客户最大容忍逗留时间内系统所处理需求量的期望值最大化双重目标,建立了模型.采用遗传算法,以武汉市某区加油站选址为例,就算法的收敛性、选址与分配方案进行讨论,并就预算B、最大容忍逗留时间T与系统时间效率关系进行分析.结果表明：B和T与系统时间效率紧密相关,且当B与T变化时,系统选址与服务台分配方案发生变化.

英文摘要：

The time efficiency is a key factor in constructing service system. Based on the queuing system of M/M/c, a location model is established considering of the dual objectives for the minimum expected travel time in the system and maximum expectation of the processing demand of the system within the maximum tolerated stay time. The case of some district gas station located in Wuhan is solved with genetic algo- rithm. The convergence of the genetic algorithm and the scheme of location-allocation are discussed. The relationship between the time efficiency of the service system and the budget B, the maximum tolerated stay time T is analyzed. The results show that B and T are closely related to the system time efficiency. Furthermore, the plan of facility location and service station distribution is changed with B and T.