1. School of Computer Science and Technology and Hubei Key Laboratory of Transportation Internet of Things, Wuhan University of Technology, Wuhan, China.
2. School of Computer Science and Technology, Wuhan University of Technology, Wuhan, China.
3. School of Computer Science and Information Engineering, Hubei University, Wuhan, China. (e-mail: wenxin.huang@whu.edu.cn)
4. School of Computer Science, Wuhan University, Wuhan, China.
5. Department of Electrical Engineering and Institute of Communications Engineering, National Tsing Hua University, Hsinchu, Taiwan.