1. School of Computer and Information Engineering, Central South University of Forestry and Technology, Changsha, China
2. School of Electronic and Information Engineering and the State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China
3. Department of Electrical and Computer Engineering, State Key Laboratory of Internet of Things for Smart City, University of Macau, Macau, China
4. School of Electronic Information, Central South University, Changsha, China