1. College of Communication and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China
2. Learning and Performance Systems Department of the College of Education, Pennsylvania State University, USA
3. Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China
4. College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China