Po-Hsueh Huang, Yin-Te Tsai+ and Chuan-Yi Tang++
Department of Computer Science and Information Engineering
Tamkang University
Taipei, 251 Taiwan
E-mail: h0138@ms7.hinet.net
+Department of Computer Science and Communication Engineering
Providence University
Taichung, 433 Taiwan
E-mail: yttsai@pu.edu.tw
++Department of Computer Science
National Tsing Hua University
Hsinchu 300, Taiwan
E-mail: cytang@cs.nthu.edu.tw