First Author:   Yi-Chi Chen Department of Economics, National Cheng Kung University yichi@ncku.edu.tw   No. 1, University Road Tainan, 701, Taiwan   +886-6-2757575#50228(Phone) +886-6-2757575#50228(Fax) Second Author: Chang-Ching Lin Institute of Economics, Academia Sinica lincc@econ.sinica.edu.tw   128 Yen-Chiu-Yuan Road, Sec. 2 Taipei, 115, Taiwan   +886-2-27822791#301(Phone) +886-2-27853946(Fax)