About the Authors

Haihua Ying

Roles Writing – review & editing

20120620@hhu.edu.cn

Affiliation School of Education Science, Nanjing Normal University, Jiangsu, China

Yang Han

Roles Investigation, Writing – original draft

Affiliation School of Computing, Nanjing University of Information Science & Technology, Jiangsu, China

Competing Interests

The authors have declared that no competing interests exist.