About the Authors

Dayi He

Affiliation School of Humanities & Economic Management, Lab of Resources & Environment Management, China University of Geosciences (Beijing), Beijing, P. R. China

Ran Li

Affiliation School of Humanities & Economic Management, Lab of Resources & Environment Management, China University of Geosciences (Beijing), Beijing, P. R. China

Qi Huang

Affiliation School of Humanities & Economic Management, Lab of Resources & Environment Management, China University of Geosciences (Beijing), Beijing, P. R. China

Ping Lei

leipingleiping@hotmail.com

Affiliation School of Humanities & Economic Management, Lab of Resources & Environment Management, China University of Geosciences (Beijing), Beijing, P. R. China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Analyzed the data: RL. Contributed to the writing of the manuscript: DH PL. Developed models: DH. Designed the numerical examples: QH.