1. Cyberspace Institute of Advanced Technology, Guangzhou University, Guangzhou, China
2. Department of Computer Science, Hong Kong Baptist University, Hong Kong SAR, China
3. Zhengzhou Xinda Institute of Advanced Technology, Zhengzhou, China
4. State Key Laboratory of Mathematical Engineering and Advanced Computing, Zhengzhou, China
5. School of Engineering and Information Technology, Australian Defence Force Academy, University of New South Wales, Canberra, ACT, Australia