1. School of Information Science and Technology, Fudan University, Shanghai, China
2. Guangdong Institute of Intelligence Science and Technology, Guangdong, China
3. Department of Computer Science and Creative Technologies, University of the West of England, Bristol, U.K.
4. Department of Computer Science, The University of Sheffield, Sheffield, U.K.
5. Department of Information Technology, Old Dominion University, Norfolk, VA, USA