国家自然科学基金91430111,61473232,61170134和国家自然科学基金青年基金61502396资助项目,互联网金融创新及监管四川省协同创新中心资助项目.This work was supported by grants from The National Natural Science Foundation of China 91430111,61473232,61170134,The National Natural Science Foundation of China Youth Fund Project 61502396,and the Internet Financial Innovation and Supervision of Collaborative Innovation Center in Sichuan Province.