1. Salhi Ahmed University CenterInstitute of Science and Technology, Department of Mathematics and Computer sciences, 45000, Naama, Algeria, Laboratory of Analysis and Control of P.D.E, University of Sidi Bel Abbes, Algeria.
2. Salhi Ahmed University CenterInstitute of Science and Technology, Department of Mathematics and Computer sciences, 45000, Naama, Algeria.
3. University Tahri Mohammed, Department of electrical engineering, 08000 Bechar, Algeria.