1. School of Software, Northwestern Polytechnical University, Xi’an, Shaanxi, China
2. School of Computer Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang, China
3. National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology, Xi’an, Shaanxi, China
4. Department of Electrical Engineering and the Institute of Communications Engineering, National Tsing Hua University, Hsinchu, Taiwan