1. Dept. of M-Commerce and Multimedia Applications, Asia Univ., No. 500, Liufeng Rd, Wufeng District, Taichung City, Taiwan 413
2. Dept. of Business Administration, National Changhua Univ. of Education, Changhua City, Changhua County 500, Taiwan (Corresponding author), e-mail: hhwu@cc.ncue.edu.tw