Bianchi G, Church R L
General Research Corp., Santa Barbara, CA 93160.
Soc Sci Med. 1988;26(1):163-71. doi: 10.1016/0277-9536(88)90055-x.
Covering models have been used to locate emergency services such as ambulance and fire protection systems. As an example, in the late seventies, an analysis of the Baltimore, Maryland fire protection system was conducted with the development and use of a covering model called the Facility Location and Equipment Emplacement Technique (FLEET). The FLEET model combined the location of fire stations with the allocation of primary and special service equipment to the stations. Further, in a recent study of Austin, Texas the ambulance system was restructured based on the use of a covering model. Covering models have also been extended to handle some of the special circumstances involved in emergency service systems. One example is the maximal expected coverage problem (MEXCLP). This paper presents a new covering model which utilizes both the special coverage structure of the MEXCLP and the simultaneous station location and equipment allocation of the FLEET model. Optimal solutions are found using linear and integer programming. Results of the model applied to several planning data sets (including a form of the Austin, Texas planning problem) demonstrate that more concentrated ambulance allocation patterns exist which may lead to easier dispatching, reduced facility costs, and better crew load balancing with little or no loss of service coverage. Tradeoff curves are presented which show that significant reductions in the number of dispatching sites (keeping the number of ambulances constant) can be made without any major changes in service level.
覆盖模型已被用于定位诸如救护车和消防系统等应急服务设施。例如，在20世纪70年代后期，利用一种名为“设施选址与设备配置技术”（FLEET）的覆盖模型，对马里兰州巴尔的摩市的消防系统进行了分析。FLEET模型将消防站的选址与主要和特殊服务设备在各站点的分配结合起来。此外，在最近对得克萨斯州奥斯汀市的一项研究中，基于覆盖模型对救护车系统进行了重组。覆盖模型也已得到扩展，以处理应急服务系统中涉及的一些特殊情况。一个例子是最大期望覆盖问题（MEXCLP）。本文提出了一种新的覆盖模型，该模型既利用了MEXCLP的特殊覆盖结构，又结合了FLEET模型中同时进行站点选址和设备分配的方法。通过线性规划和整数规划找到最优解。将该模型应用于多个规划数据集（包括得克萨斯州奥斯汀市规划问题的一种形式）的结果表明，存在更集中的救护车分配模式，这可能导致调度更容易、设施成本降低以及机组人员负载平衡更好，而服务覆盖几乎没有损失。给出了权衡曲线，表明在不改变服务水平的情况下，可以大幅减少调度站点的数量（保持救护车数量不变）。
