[1] Tianjin Polytech Univ, Dept Math, Tianjin 300160, Peoples R China
[2] Cheng Shiu Univ, Dept Informat Management, Kaohsiung 833, Taiwan
[3] Gyeongsang Natl Univ, Dept Math, Jinju 660701, South Korea
[4] Gyeongsang Natl Univ, RINS, Jinju 660701, South Korea