1. School of Computer Science, Hubei Key Laboratory of Intelligent Geo-Information Processing, China University of Geosciences, Wuhan, China
2. School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
3. Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
4. Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
5. School of Computer Science, The University of Sydney, Camperdown, NSW, Australia