1. School of Computer Engineering, Jiangsu Ocean University, Lianyungang, Jiangsu 222003, China
2. School of Mathematics and Information Engineering, Lianyungang Normal College, Lianyungang, Jiangsu 222003, China
3. College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics Nanjing, Jiangsu 210016, China
4. J. B Speed School of Engineering, University of Louisville, KY 40208, USA