First Author:   Shiro Kuwahara Graduate School of Economics, Kyoto University kuwahala@mbox.kyoto-inet.or.jp   Mori Mansion V 305, Ichijoji Jizomotocho 21-1, Sakyoku Kyoto, 606-8181, Japan   +81-75-722-1050(Phone) +81-75-722-1050(Fax) http://www.geocities.jp/kuwahala/index.html