About the Authors

Mei Ma

Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Validation, Writing – original draft, Writing – review & editing

Current Address: School of Computer Science, Shaanxi Normal University, Xi’an, China.

Affiliations School of Computer Science, Shaanxi Normal University, Xi’an, China, School of Mathematics and Statistics, Qinghai Normal University, Qinghai, China

Xiujuan Lei

Roles Conceptualization, Formal analysis, Funding acquisition, Investigation, Methodology, Supervision, Writing – review & editing

xjlei@snnu.edu.cn

Current Address: School of Computer Science, Shaanxi Normal University, Xi’an, China.

Affiliation School of Computer Science, Shaanxi Normal University, Xi’an, China

Competing Interests

The authors have declared that no competing interests exist.