1. Department of Electrical Engineering, National Penghu University of Science and Technology, Penghu 88046, Taiwan
2. Department of Electrical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
3. Department of Computer Science and Information Engineering, National Taipei University, New Taipei City 23741, Taiwan
4. Department of Information and Communication Engineering, Chaoyang University of Technology, Taichung 41349, Taiwan