1. School of Information and Communication Engineering, Xi’an Jiaotong University, Xi’an, China
2. Computer Science Department, Community College, King Saud University, Riyadh, Saudi Arabia
3. Graduate School of Science and Engineering, Hosei University, Tokyo, Japan
4. Department of Information Systems, University of Maryland at Baltimore County, Baltimore, MD, USA
5. School of Computer Science, University of Technology Sydney, Sydney, NSW, Australia