About the Authors

Liangdong Hu

Affiliation Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, Jilin University, Changchun, Jilin, P. R. China

Limin Wang

wanglim@jlu.edu.cn

Affiliation Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, Jilin University, Changchun, Jilin, P. R. China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: LDH LMW. Performed the experiments: LDH LMW. Analyzed the data: LDH LMW. Wrote the paper: LDH.