1. Department of Computer Science, University of Yaoundé I, Yaounde, Cameroon
2. IRD, UMMISCO, Sorbonne University, Paris, France
3. IMT Nord Europe, Institut Mines-Télécom, Centre for Digital Systems, Lille, France
4. University Clermont Auvergne, CNRS, ENSMSE, LIMOS, Clermont-Ferrand, France