1. Department of Electronic Engineering, National University of Tainan, No. 33, Section 2, Shu Lin Street, Tainan 700, Taiwan, Republic of China
2. Department of Electrical and Control Engineering, National Chiao Tung University, No. 1001, Ta Hsueh Road, Hsinchu 30010, Taiwan, Republic of China
3. Department of Computer Science and Information Engineering, National United University, No. 1, Lien Da, Kung Ching Li, Miaoli 360, Taiwan, Republic of China