1. School of Information Technology, Yancheng Institute of Technology, Yancheng, China
2. School of Physics and Electronic Information Engineering, Henan Polytechnic University, Jiaozuo, China
3. College of Engineering, IT and Environment, Charles Darwin University, Casuarina, NT, Australia
4. Department of Computer Science and Engineering, School of Technology, Pandit Deendayal Energy University, Gandhinagar, India
5. School of Space Information, Space Engineering University, Beijing, China