First Author:   Juanjuan Zhuo Nippon Bunri University takukk@nbu.ac.jp   1727 Ichigi Oita-shi, 8700397, Japan   +81-97-524-2680(Phone) +81-97-524-2680(Fax) Second Author: Masao Kumamoto Hitotsubashi University masao.kumamoto@r.hit-u.ac.jp   Kunitachi-shi, 1868601, Japan   +81-42-580-8747(Phone)