University of Yaounde I - Nonlinear Physics and Complex Systems GroupUniversity of Douala, Faculty of Science, Department of Physics, Pure Physics Laboratory, Group of Nonlinear Physics and Complex Systems, Bangabandhu Sheikh Mujibur Rahman Science and Technology University - Department of Mathematics, University of Dschang - Laboratoire dAutomatique et Informatique Apliqu´ee (LAIA), University of Douala - Pure Physics Laboratory, University of Douala - Fundamental Physics Laboratory and University of Yaounde I - Nonlinear Physics and Complex Systems Group