First Author:   Takuma Kamada Graduate School of Arts and Letters, Tohoku University takuma206@gmail.com   27-1 Kawauchi Aoba-ku Sendai, 980-8576, Japan   +81-22-795-6037(Phone) +81-22-795-6037(Fax) Second Author: Hajime Katayama School of Commerce, Waseda University hajime.katayama@waseda.jp   1-6-1 Nishi-Waseda, 1-6-1 Nishi-Waseda Shinjuku, 169-8050, Japan