[1]School of Mathematics and Statistics, Chifeng University, Inner Mongolia 024000, P. R. China;
[1]School of Mathematics and Statistics, Chifeng University, Inner Mongolia 024000, P. R. China;
[1]School of Mathematics and Statistics, Chifeng University, Inner Mongolia 024000, P. R. China;
[2]School of Computer and Information Engineering, Chifeng University, Inner Mongolia 024000, P. R. China;