Ching-Hung Wang#, Shian-Shyong Tseng and Tzung-Pei Hong*
Institute of Computer and Information Science
National Chiao Tung University
Hsinchu, 300, Taiwan, R.O.C.
*Department of Information Management
Kaohsiung Polytechnic Institute
Kaohsiung, 800, Taiwan, R.O.C.
#Directorate General of Telecommunication Laboratories
Ministry of Transportation and Communications
Chung-Li, 320, Taiwan, R.O.C.