1. Guangdong Key Laboratory of Information Security, and School of Computer Science and Engineering, Sun Yat-sen University, Guangzhou, China
2. School of Electrical and Electrics Engineering, Nanyang Technological University, Jurong West, Singapore
3. Guangdong Key Laboratory of Intelligent Information Processing, and the National Engineering Laboratory for Big Data System Computing Technology, Shenzhen University, Shenzhen, China
4. School of Electronic and Information Engineering, South China University of Technology, Guangzhou, China
5. School of Electrical and Electronic Engineering, Nanyang Technology University, 50 Nanyang Ave, Singapore