1. School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
2. College of Computer Science and Electronic Engineering, Hunan University, Changsha 410082, China
3. Computer Science Department, University of California at Los Angeles, USA
4. Fujian Key Laboratory of Automotive Electronics and Electric Drive (Fujian University of Technology), Fuzhou 350118, China
5. Department of Computer Science and Information Engineering, Providence University, Taichung 43301, Taiwan