First Author:   Kenichi Shiraishi Faculty of Social Welfare, Gunma University of Health and Welfare shiraishi@shoken-gakuen.ac.jp         Second Author: Kazuto Sumita Faculty of Economics, Toyo University sumita@toyo.jp         Third Author: Kazuki Kamimura Faculty of Economics, Toyo University kamimura107@toyo.jp         Fourth Author: Shohei Okamoto Department of Policy and Planning Sciences, University of Tsukuba okamotos@sk.tsukuba.ac.jp         Five Author: Kohei Komamura Faculty of Economics, Keio University bzr05433@nifty.ne.jp