Gwo-Jen Hwang**, Jia-Lin Hsiao+ and Judy C. R. Tseng++
**Informatiion Management Department
National Chi Nan University
Puli, Nan-Tou, 545 Taiwan
E-mail: gjhwang@ncnu.edu.tw
+Information Management Department
Ling Tung College
Taichung, 400 Taiwan
E-mail: jialin@mail.ltc.edu.tw
++Department of Computer Science and Information Engineering
Chung Hua University
E-mail: judycrt@chu.edu.tw