1. School of Computer Science, Key Laboratory of Hunan Province for Internet of Things and Information Security, and the Hunan International Scientific and Technological Cooperation Base of Intelligent Network, Xiangtan University, Xiangtan, China
2. Department of Electrical and Computer Engineering, Ajou University, Suwon, South Korea
3. School of Information and Communications Engineering, Xi'an Jiaotong University, Xi'An, Shaanxi, China