1. Department of Electrical Engineering, National Cheng-Kung University, Tainan, Taiwan, R.O.C
2. Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan, Taiwan, R.O.C
3. Department of Electrical and Computer Engineering, University of Houston, Houston, TX, USA
4. Electrical Engineering School, Universidad del Zulia, Maracaibo, Venezuela