First Author:   Mototsugu Fukushige Graduate School of Economics, Osaka University mfuku@econ.osaka-u.ac.jp   Toyonaka, 560-0043, Japan   +81-6-6850-5248(Phone) +81-6-6850-5248(Fax) Second Author: Kazuki Okamoto JIM Technology Corporation kazukiok.1104@gmail.comp