1. School of Computer Science and Engineering, Central South University, Changsha, China
2. Department of Computer Science and Mathematics, Sul Ross State University, Alpine, TX, USA
3. School of Computer Science and Engineering, Hunan University of Science and Technology, Xiangtan, China
4. Institute of Artificial Intelligence and Future Networks, Beijing Normal University and UIC, Zhuhai, China
5. Department of Information and Electronic Engineering, Muroran Institute of Technology, Muroran, Japan