Dao-zhi Zeng Tohoku University   Tohoku University Tohoku University Aramaki aza Aoba 6-3-09, Aoba-ku Sendai, Miyagi 980-8579 Japan   zeng@se.is.tohoku.ac.jp   http://www.se.is.tohoku.ac.jp/~zeng/index.html           JEL Areas: R3 : Production Analysis and Firm Location: General L2 : Firm Objectives, Organization, and Behavior: General