1. School of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China
2. Microsoft, Redmond, WA, USA
3. School of Science and Technology, Hong Kong Metropolitan University, Hong Kong, China
4. Department of Computing and Decision Sciences, Lingnan University, Hong Kong, China
5. Department of Geography and Environmental Management and the Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada
6. Shenzhen Research Institute, Nanjing University of Aeronautics and Astronautics, Shenzhen, China