1. Department of Intelligent Robotics, National Pingtung University, Pingtung 900, Taiwan
2. Department of Electrical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 807, Taiwan
3. Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University, Kaohsiung 807, Taiwan
4. Department of Mechanical and Computer-Aided Engineering, Feng-Chia University, Taichung 407, Taiwan