1. College of Electronic and Information Engineering, Guangdong Ocean University, Zhanjiang, Guangdong, China
2. School of Information Science and Engineering, Yanshan University, Qinhuangdao, Hebei, China
3. Hebei Key Laboratory of Virtual Technology and System Integration, Qinhuangdao, Hebei, China
4. College of Computer and Information Technology, Northeast Petroleum University, Qinhuangdao, Hebei, China