Shingo Takahashi is an Associate Professor at the Graduate School for International Development and Cooperation, Hiroshima University. Hideo Owan is a Professor at the School of Political Science and Economics, Waseda University. Tsuyoshi Tsuru is Professor Emeritus and a visiting faculty member at the Institute of Economic Research, Hitotsubashi University. Katsuhito Uehara is an Associate Professor at the School of Management and Information, University of Shizuoka