[Lin, Ren] Southwest Jiaotong Univ, Sch Econ & Management, Chengdu 610031, Peoples R China.
[Zhou, Guohua; Lin, Ren] Hunan City Univ, Coll Math & Comp Sci, Yiyang 413000, Peoples R China.
[Liu, Aijun] Xidian Univ, Sch Econ & Management, Xian 710071, Peoples R China.
[Lu, Hui] Shanghai Normal Univ, Tianhua Coll, Shanghai 201815, Peoples R China.
[Li, Tonglei] Hebei Vocat Coll Correct Police, Dept Informat & Technol, Shijiazhuang, Hebei, Peoples R China.