1. School of Mathematics and Computational Science, Xiangtan University, Xiangtan, Hunan, China
2. Key Laboratory of Intelligent Computing and Information Processing of the Ministry of Education, Xiangtan University, Xiangtan, Hunan, China
3. School of Physics and Optoelectronic Engineering, Xiangtan University, Xiangtan, Hunan, China
4. School of Computer Science, Xiangtan University, Xiangtan, Hunan, China