1. School of Computer Science and Engineering, Xi'an University of Technology, Xi'an 710048, China
2. School of Electronic and Information Engineering, Ankang University, Ankang 725000, China
3. The Key Laboratory of Industrial Automation of Shaanxi Province, Shaanxi University of Technology, Hanzhong 723001, China
4. College of Information and Communication, National University of Defense Technology, Wuhan 430019, China