Shian-Shyong Tseng, Bertrand M. T. Lin* and Sue Huei Liu#
Department of Computer and Information Science
National Chiao-Tung University
Hsinchu, Taiwan 300, R.O.C.
* Department of Information Management
Ming-Chuan University
Taipei 111, R.O.C.
# Department of Computer Science and Information Engineering
National Chiao-Tung University
Hsinchu, Taiwan 300, R.O.C.