1. School of Economics and Management, Beijing University of Posts and Telecommunications, Beijing, China
2. School of Computer Science and Technology, Guizhou University, Guiyang, China
3. Research Center of Maritime Security Technology, China Waterborne Transport Research Institute, Beijing, China
4. School of Software Engineering, Beijing University of Posts and Telecommunications, Beijing, China
5. Institute of Network Technology, Beijing University of Posts and Telecommunications, Beijing, China