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

(1)分析了基于大城市内部迁移空间相互作用模型的距离衰减参数估计。这里的研究区域是由统计局管理协调厅在1990年人口普查中确定的凯罕申都会区。参数估计在研究区域的东半部倾向于较小的负值，而在西半部则是较大的负值，这种变化受研究区域内有关单元区的位置的影响。因此，通过替换将估计值作为因变量的函数和将位置数据(经度和纬度)作为自变量的函数，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，距离衰变参数的新估计并不一定与以前的论点有令人满意的联系。(2)通过时间序列分析，阐明了20世纪70年代以来日本移民系统的主要焦点--东京都近期移民变化的潜在因素。3)关于20世纪70年代和80年代观察到的移民转向，我们假设人口事件(特别是战后生育率变化导致年轻人供应的变化)是可能的原因。然后，利用偏离份额分析确定了其贡献。

(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.