1. School of Computer Science and Engineering and the Guangxi Key Laboratory of Embedded Technology and Intelligent System, Guilin University of Technology, Guilin, China
2. College of Electronics and Information Engineering, Shenzhen University, Shenzhen, China
3. School of Computer Science and Information Engineering, Hubei University, Wuhan, China
4. School of Cyberspace Science and Technology, Beijing Institute of Technology, Beijing, China