1. State Key Laboratory of Integrated Service Networks, Xidian University, Xi'an, China
2. Department of Mathematics, Chaudhary Charan Singh University, Meerut, India
3. Department of Computer Science and Engineering, Ajay Kumar Garg Engineering College, Ghaziabad, India
4. College of Computer Science and Technology, China University of Petroleum (East China), Qingdao, China