1. School of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China
2. Shenzhen Research Institute, Nanjing University of Aeronautics and Astronautics, Shenzhen, China
3. Fujian Key Laboratory of Sensing and Computing for Smart Cities, School of Informatics, Xiamen University, Xiamen, China
4. Department of Electrical, Computer and Biomedical Engineering, Ryerson University, Toronto, ON, Canada
5. Department of Geography and Environmental Management and the Department of Systems Design Engineering, University of Waterloo, Waterloo, ON, Canada