Affiliation: | 1. Faculty of Mathematics and Computer Sciences, Department of Applied Mathematics , Amirkabir University of Technology , No. 424, Hafez Avenue , Tehran 15914 , Iran mdehghan@aut.ac.ir;3. Faculty of Mathematics and Computer Sciences, Department of Applied Mathematics , Amirkabir University of Technology , No. 424, Hafez Avenue , Tehran 15914 , Iran;4. Faculty of Mathematical Sciences, Department of Mathematics , Shahid Beheshti University , Evin , Tehran 19839 , Iran |