1. Department of Mathematics, Faculty of Sciences of Sfax, University of Sfax, Sfax 1171, Tunisia
2. ENSIIE, University of Evry-Val-d’Essonne, 1 square de la Résistance, CEDEX, 91025 Evry-Courcouronnes, France
3. Department of Statistics and Operations Research, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia