1. Department of Computer Science and Information Engineering, National Central University, Taoyuan 320, Taiwan
2. Department of Biomedical Sciences and Engineering, National Central University, Taoyuan 320, Taiwan
3. Department of Computer Science, University of Warwick, Coventry CV47AL, UK
4. Department of Computer Science and Information Engineering, Providence University, Taichung 43301, Taiwan
5. AI Research Center, Hon Hai Research Institute, New Taipei City 236, Taiwan