Humanities and Social Sciences Foundation for the Youth Scholars of Ministry of Education of China [15YJCZH066]; Science and Technology Plan Project of Hunan Province [2016TP1020]; Science and Technology Plan Project of Hengyang City [2017KJ183]; Application-Oriented Characterized Disciplines, Double FirstClass University Project of Hunan Province [Xiangjiaotong [2018]469]; Hunan Provincial Natural Science Foundation of ChinaNatural Science Foundation of Hunan Province [2018JJ2006, 2018JJ4024]; National Statistical Science Research Project of China [2018LY05]; Scientic Research Fund of Hunan Provincial Education DepartmentHunan Provincial Education Department [17A030, 18C0660]