1. College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, China
2. School of Computer and Information Engineering, Shanghai Polytechnic University, Shanghai, China
3. Department of Information Technology and Decision Science, Old Dominion University, Norfolk, VA, USA
4. School of Information and Electromechanical Engineering, Jiangsu Open University, Nanjing, Jiangsu, China