title: Spatial optimization of residential care facility locations in Beijing, China: maximum equity in accessibility.
abstract: BACKGROUND
  The residential care system is rapidly developing and plays an increasingly important role in care for the elderly in Beijing. A noticeable disparity in the accessibility to existing residential care facilities, however, is demonstrated in existing studies. The spatial optimization of residential care facility (RCF) locations is urgently needed to promote equal access to residential care resources among the elderly population.
  
  
  METHODS
  A two-step floating catchment area method with an additional distance-decay function is adopted to measure accessibility to residential care facilities. The spatial optimization model is developed to maximize equity in accessibility by minimizing the total square difference between the accessibility score of each demand location and the weighted average accessibility score. The Particle Swarm Optimization (PSO) method is implemented for the solution.
  
  
  RESULTS
  The optimized RCF layouts improve equal spatial access to residential care resources with very low accessibility standard variation (0.0066). A relatively large number of beds (51% of the total beds) to be located in the suburban districts between the central and periphery districts of Beijing are optimized. A smaller number of beds to be located in the central and periphery districts (33% and 16% respectively) are optimized. The gaps between the existing and optimized layouts suggest that more RCF beds (5961 beds) are needed in suburban districts, while the RCF beds in some subdistricts located in the central and periphery districts are oversupplied (5253 and 1584 surplus beds respectively).
  
  
  CONCLUSIONS
  The optimized results correspond to the municipal special plan proposed by the Beijing government. The optimization objective of this study is different from traditional facility location optimization models, and the method is efficient in maximizing equal access to residential care facilities. This method can support knowledge-based policy-making and planning of residential care facilities.
authors.forename: Zhuolin
authors.initials: Z
authors.lastname: Tao
authors.affiliation: School of Geography, Beijing Normal University, 19 Xinjiekouwai Avenue, Beijing 100875, China. chengyang@bnu.edu.cn.
authors.forename: Yang
authors.initials: Y
authors.lastname: Cheng
authors.forename: Teqi
authors.initials: T
authors.lastname: Dai
authors.forename: Mark W
authors.initials: MW
authors.lastname: Rosenberg
mesh_terms: D000368:Aged; D002681:China / Q000208:ethnology; D006297:Health Services Accessibility / Q000592:standards*; D054625:Healthcare Disparities / Q000208:ethnology* / Q000592:standards*; D006801:Humans; D011159:Population Surveillance / Q000379:methods; D012112:Residential Facilities / Q000592:standards*