First Author:   Shyh-Wei Chen Department of Economics, Tunghai University schen@mail.thu.edu.tw   No 181, Section 3, Taichung-Kun Road Taichung, Taiwan Taichung, 407-04, Republic of China   886-4-23590121ext2922(Phone) 886-4-23590121ext2922(Fax) http://geocities.com/chen_shyhwei/