1. School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing, China
2. College of Science of Engineering, James Cook University, Townsville, QLD, Australia
3. School of Computer Science and Information Security, Guilin University of Electronic Technology, Guilin, Guangxi, China
4. School of Software and Electrical Engineering, Swinburne University of Technology, Hawthorn, VIC, Australia