1. Artificial Intelligence Graduate Program, National Yang Ming Chiao Tung Univresity, Hsinchu, Taiwan
2. Institute of Electronics, National Yang Ming Chiao Tung Univresity, Hsinchu, Taiwan
3. Computer Science and Engineering, University of California, San Diego, La Jolla, USA
4. Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
5. Department of Computer Science and Information Engineering, National Taiwan University (NTU), Taipei, Taiwan