About the Authors

Xiaofei Li

Affiliation College of Information Science and Technology, Beijing Normal University, Beijing, China

Li Yao

Affiliations College of Information Science and Technology, Beijing Normal University, Beijing, China, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China

Qing Ye

Affiliation College of Information Science and Technology, Beijing Normal University, Beijing, China

Xiaojie Zhao

zhaoxj86@hotmail.com

Affiliation College of Information Science and Technology, Beijing Normal University, Beijing, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: LY XZ. Performed the experiments: QY. Analyzed the data: XL. Wrote the paper: XL XZ.