[1] Shandong Univ Finance & Econ, Sch Management Sci & Engn, Jinan, Peoples R China
[2] Shandong Univ Finance & Econ, Sch Int Trade & Econ, Jinan, Shandong, Peoples R China
[3] Univ Ghent, Dept Data Anal & Math Modelling, KERMIT, Coupure Links 653, B-9000 Ghent, Belgium
[4] Shandong Womens Univ, Sch Econ, Jinan, Peoples R China
[5] Southeast Univ, Sch Econ & Management, Nanjing, Peoples R China