1. College of Computer Science and Electronic Engineering, Hunan University, Changsha, China
2. School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo, China
3. School of Space Information, Space Engineering University, Beijing, China
4. School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan, China
5. Department of Information Systems, University of Maryland, Baltimore County (UMBC), Baltimore, MD, USA
6. Department of Computer Science and Engineering, School of Technology, Pandit Deendayal Energy University, Gandhinagar, India