1. School of Computer Science, Nanjing University of Information Science and Technology, Nanjing, China
2. Department of Computer and Electronics Systems Engineering, Hankuk University of Foreign Studies, Yongin-si, South Korea
3. College of Mathematics and Information Science, Nanjing Normal University of Special Education, Nanjing, China
4. School of Computer Science, University of Petroleum and Energy Studies, Dehradun, India
5. Faculty of Mathematics, University of Waterloo, Waterloo, ON, Canada
6. State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing, China