Department of Statistics, University of Missouri, Columbia, Missouri, USA. hwg58@mail.missouri.edu.|Department of Statistics, University of Missouri, Columbia, Missouri, USA. hezh@missouri.edu.|Department of Computer Science and Informatics Institute, Columbia, USA. gk3kc@mail.missouri.edu.|Department of Computer Science and Informatics Institute, Columbia, USA. xudong@missouri.edu.|Department of Applied Economics and Statistics, University of Delaware, Newark, DE, USA. qiujing@udel.edu.