1. College of Computer Science and Electronic Engineering, Hunan University, Changsha, Hunan, China
2. College of Engineering, IT and Environment, Charles Darwin University, Darwin, Australia
3. Department of Computer Science and Engineering, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
4. Department of Mathematics and Computer Science, University of Exeter, Exeter, U.K.
5. TU Wien, Vienna, Austria
6. School of Computing Science, Simon Fraser University, Burnaby, BC, Canada