1. School of Information Engineering, Ningxia University, Yinchuan 750021, China
2. Ningxia Key Laboratory of Artificial Intelligence and Information Security for Channeling Computing Resources from the East to the West, Yinchuan 750021, China
3. Collaborative Innovation Center for Ningxia Big Data and Artificial Intelligence Co-Founded by Ningxia Municipality and Ministry of Education, Yinchuan 750021, China