中文摘要：

研究了连锁型企业新设施选址的2个重要因素：市场份额的划分和设施的服务半径。依照效用函数为竞争环境下设施市场份额分配的重要依据，结合消费者的空间选择行为提出了阶梯型效用函数，并应用此效用函数建立了一个竞争环境下连锁型企业新设施选址的新模型，此模型既考虑了服务设施覆盖衰退又考虑了设施的服务半径。最后，给出了求解模型的遗传算法和具体案例。结果表明，该模型和算法可以用于连锁型企业新设施选址决策中，并能够有效地得到问题的近似解。

英文摘要：

This paper studies two important factors of the location of new facilities of the chaincompanies： the allocation of market share and service radius of facilities. Considering the spatial customer choice,we use step utility function to construct a new model of a chain-company＇s new facilities location in competitive environment based on the fact that the utility function is an important factor of the allocation of market share of facilities in a competitive environment. Both the decay cover and the service radius of facilities are considered in the model. The genetic algorithm to solve this model is developed and computational experiment is described. The result shows that this model and algorithm is suitable for the location decision of the chain-company＇s new facilities ,and could efficiently obtain an approximate solution.