1. Math Department, King Abdulaziz University, Jeddah 21589, Saudi Arabia
2. I2M, (Aix Marseille Univ., CNRS, Centrale Marseille), 13009 Marseilles, France
3. Faculty of Engineering, Ain Shams University, Cairo 11517, Egypt
4. Egypt University of Informatics, Knowledge City, New Administrative Capital, Cairo, Egypt