Research in Spatial Variation of Distance-decay Effect in Intra-metropolitan Migration

(1)距离衰减参数估计来自大都市内迁移的空间相互作用模型进行了分析。这里的研究区域是京坂神都市圈，由统计局管理和协调机构在1990年人口普查中定义。参数估计值在研究区东半部的负值较小，而在研究区西半部的负值较大，这种变化受研究区内有关单位面积位置的影响。因此，通过将以估计值为因变量、以位置数据（经度和纬度）为自变量的函数代入，将初始模型“扩展”为终端模型。这是Casetti展开法的一个应用。然而，距离衰减参数的新估计不一定与以前的论点令人满意。(2)通过时间序列分析，揭示了日本人口迁移体系的焦点之一--东京都地区自20世纪70年代以来人口迁移变化的潜在因素。3）关于20世纪70年代和80年代的人口迁移转变，我们假设人口事件（具体而言，由于战后生育率的变化，年轻成年人的供应发生变化）是一个可能的原因。然后，通过偏离-份额分析，确认其贡献。

(1) Distance-decay parameter estimates derived from the spatial interaction model for intra-metropolitan migration were analyzed. The study area here was the Keihanshin Metropolitan Area, defined in 1990 population census by the Statistics Bureau, Management and Coordination Agency. The parameter estimates tended to be less negative in eastern half of the study area, while more negative in western half.Such a variation were influenced by location of the unit areas concerned within the study area. Thus, the initial model was "expanded" into the terminal model by substituting the function having the estimates as dependent variable and location data (longitude and latitude) as independent variables. This is an application of Casetti's expansion method. However, new estimates of distance-decay parameter were not necessarily linked with previous arguments satisfactorily.(2) Under lying factors of recent migration changes of the Tokyo Metropolitan Area since the 1970s, a major focal point of the Japanese migration system, were elucidated by time-series analyzes.3) With regard to the migration turnarounds observed in the decades of the 1970s and 1980s, we assumed the demographic event (specifically, changing supply of young adults due to changing fertility in the postwar period) as a possible cause. Then, its contribution was confirmed by using the shift-share analysis.