1. Jiangsu Key Laboratory of Big Data Security and Intelligent Processing, Nanjing University of Posts and Telecommunications, Nanjing, China
2. School of Computer Science, Nanjing University of Posts and Telecommunications, Nanjing, China
3. Department of Computer Science, Edge Hill University, Ormskirk, U.K
4. Department of Computer Science, University of Salerno, Fisciano, Italy