1. Ton Duc Thang University, Ho Chi Minh City, Vietnam
2. Center for Nonlinear Systems, Chennai Institute of Technology, Malayambakkam, India
3. Department of Telecommunication and Network Engineering, IUT-Fotso Victor of Bandjoun, University of Dschang, P. O. Box: 134, Bandjoun, Cameroon
4. Center for Nonlinear Dynamics, Defence University, Bishoftu, Ethiopia