1. Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan, R.O.C.
2. Department of Engineering Science and the Institute of Computer and Communication Engineering, National Cheng Kung University, Tainan, Taiwan, R.O.C.
3. School of Computer Science and Electronic Engineering, University of Essex, United Kingdom
4. Department of Electrical Engineering and the Institute of Computer and Communication Engineering, National Cheng Kung University, Tainan, Taiwan, R.O.C.