[1] Nanjing Univ Informat Sci & Technol, Sch Math & Stat, Nanjing 210044, Peoples R China
[2] Nanjing Univ Informat Sci & Technol, Ctr Appl Math Jiangsu Prov, Nanjing 210044, Peoples R China
[3] Nanjing Univ Informat Sci & Technol, Jiangsu Int Joint Lab Syst Modeling & Data Anal, Nanjing 210044, Peoples R China
[4] Korea Univ, Dept Math, Seoul 02841, South Korea