1. College of Electronic and Control Engineering, Beijing University of Technology, Beijing, Beijing, China, 100124 (e-mail: rechard112@163.com)
2. Faculty of Information Technology, Beijing university of technology, Beijing, China, 100000 (e-mail: cd_student_lhx@sina.com)
3. Faculty of Information Technology, Beijing University of Technology, 12496 Beijing, Beijing, China, (e-mail: liuzheng709@emails.bjut.edu.cn)
4. College of Electronic and Control Engineering, Beijing University of Technology, Beijing, China, 100124 (e-mail: isibox@sina.com)