First Author:   Tetsuo Ono Graduate School of Economics, Osaka University tono@econ.osaka-u.ac.jp   1-7, Machikaneyama Toyonaka, 560-0043, Japan       Second Author: Ryo Arawatari Graduate School of Economics, Osaka University ege001ar@mail2.econ.osaka-u.ac.jp   1-7, Machikaneyama Toyonaka, 560-0043, Japan