National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [11961015]; Natural Science Foundation of GuangxiNational Natural Science Foundation of Guangxi Province [2019GXNSFAA245031, 2018GXNSFBA281019]; Foundation of Guilin University of Technology [GUTQDJJ2004044]; Scientific Research Fund of Hunan Provincial Education DepartmentHunan Provincial Education Department [18C0660]; National Statistical Science Research Project of China [2018LY05]; State Scholarship Fund of China Scholarship CouncilChina Scholarship Council [201908430242]