1. School of Mathematics and Computer Science, Northwest Minzu University, Lanzhou 730000, China
2. Key Laboratory of Streaming Data Computing Technologies and Application, Northwest Minzu University, Lanzhou 730000, China
3. Key Laboratory of China’s Ethnic Languages and Information Technology of Ministry of Education, Northwest Minzu University, Lanzhou 730000, China
4. School of Mathematics and Computer Science, Xiangtan University, Hunan 411105, China