基金partly supported by the China Postdoctoral Science Foundation(Grant No.2017M610156)the National Natural Science Foundation of China(Grant No.11501167)the Young Academic Leaders Project of Henan University of Science and Technology(Grant No.13490008)
基金the National Natural Science Foundation of China(10431010)the MOE Project of Key Research Institute of Humanities and Social Sciences in Universities (05JJD910001)Center for Applied Statistics of Renmin University of China