About the Authors

Gang wei Wang

pukai1121@163.com

Affiliation School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, PR China

Tian zhou Xu

Affiliation School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, PR China

Tao Feng

Affiliation School of Electrical Engineering, Yanshan University, Qinhuangdao, PR China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Wrote the paper: GwW TzX TF.