1. Naval Submarine Academy, Qingdao, China
2. School of Space Information, Space Engineering University, Beijing, China
3. School of Physics and Electronics Information Engineering, Henan Polytechnic University, Jiaozuo, China
4. School of Computing and Mathematics, University of Leicester, Leicester, U.K.
5. School of Computer Science and Technology, Henan Polytechnic University, Jiaozuo, China
6. Department of Information Systems, University of Maryland at Baltimore County, Baltimore, MD, USA