Affiliation: | 1. Department of Mathematics, Taiyuan University of Technology, Taiyuan Shanxi-030024, China;2. Laboratoire de Recherche en Informatique, UMR 8623, C.N.R.S.-Université de Paris-sud, 91405-Orsay cedex, France;3. Jianghan University Institute for Interdisciplinary Research, Jianghan University, Wuhan Hubei-430056, China |