1. Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen, China
2. State Key Laboratory of Integrated Services Networks, Xidian University, Xi’an, China
3. Faculty of Computer Science, University of New Brunswick, Fredericton, NB, Canada
4. Software Engineering Institute, East China Normal University, Shanghai, China
5. School of Geography and Information Engineering, China University of Geosciences, Wuhan, China