1. College of Information and Computer, Taiyuan University of Technology, Taiyuan 030024, China
2. College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, China
3. School of Electronic Information Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China
4. Shanxi Key Laboratory of Advanced Control and Intelligent Information System, Taiyuan University of Science and Technology, Taiyuan 030024, China
5. Department of Computer Engineering, San Jose State University, San Jose, CA, USA