1. School of Computer Science and Engineering, South China University of Technology, Guangzhou, China
2. School of Information Engineering, Nanchang University, Nanchang, China
3. Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
4. School of Computer Science and Engineering, Guangdong University of Technology, Guangzhou, China
5. Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada