Subjects: Geosciences >> Geography Subjects: Mathematics >> Control and Optimization. submitted time 2023-05-13
Abstract： Location problems have been widely applied to service planning of public health, compulsory education, emergency management, and delivery logistics. However, the mainstream location models are usually to optimize the efficiency objectives such as travel cost, facility cost and the number of customs to be served, rather than the equality objectives. A few location models aim to optimize one of the equality measures, such as the variance of distances, the deviation of distances, the Gini coefficient between the travel distances, and the variance of spatial accessibility indexes. However, the facility locations, capacities and their service areas can be easily distorted by most equality-oriented objective functions. In this paper, a spatially envy objective function for service equality is proposed to overcome the shortcomings of commonly used equality functions. The envy value of customers at a location is determined by their travel distance that beyond a predefined distance. The envy function can be added to mainstream location models in a weighted manner. As a result, the capacitated p-median problem (CPMP) is enhanced as CPMP-envy. The original and improved models were tested on three large instances. Case experiments show that the equality measures, such as maximum travel distance, variance of distances, coefficient of variation, and Gini coefficient between travel distances, can be substantially improved by minimizing the weighted sum of spatial envy and travel cost. It is argued that the envy indicator has theoretical and practical potentials in facility planning towards spatial equality of public service.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Geography submitted time 2021-01-19
Abstract： 空间可达性是衡量公共服务设施公平性的重要指标，在医疗、教育、休闲等公共服务的布局规划中得到广泛应用。然而，现有可达性模型难以充分反映服务供需关系，计算指标也缺乏物理意义。本文提出新的可达性计算方法取代现有方法。该方法基于最优供需分配模型，将设施服务分配给需求者，根据分配结果计算空间可达性指标。给定服务设施与需求的空间分布，以最小化旅行成本为目标，顾及设施服务能力，采用经典的运输问题模型确定最优的服务供需分配方案，进而度量服务的空间可达性。以郑州市某区社区卫生服务为例，求解 25个中心与1333个居住小区的最优服务配置。使用最优配置结果确定每个设施的服务范围、每个居住小区使用服务的旅行时间，以及特定时间阈值的服务覆盖比率。与流行的两步移动搜索法相比，新方法的计算指标具有明确的物理意义。本文提出的可达性评价方法无需参数，计算高效，结果易于解释，在公共服务评价及设施布局规划方面具有应用潜力。
Peer Review Status:Awaiting Review
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