About the Authors

Yazhi Liu

Affiliation College of Information, North China University of Science and Technology, Tangshan 063009, China

Xiong Li

lixiongzhq@163.com

Affiliation School of Computer Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: YL XL. Performed the experiments: YL. Analyzed the data: YL XL. Contributed reagents/materials/analysis tools: YL XL. Wrote the paper: YL XL.