1. Department of Electrical EngineeringUniversity of Bojnord Bojnord Iran
2. Department of MathematicsSahand University of Technology Tabriz Iran
3. Department of Electrical and Computer EngineeringHakim Sabzevari University Sabzevar Iran
4. Department of Mathematics, Faculty of Arts and SciencesCankaya University Ankara Turkey
5. Institute of Space Sciences Măgurele Romania