1. a Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
2. b Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
3. c Department of Electrical Engineering, National University of Kaohsiung, Kaohsiung, Taiwan
4. d Department of Chemical and Materials Engineering, National University of Kaohsiung, Kaohsiung, Taiwan
5. e Department of Electronic Engineering, Graduate Institute of Computer and Communication Engineering, National Taipei University of Technology, Taiwan