First Author:   Chaker Aloui Mr IFGT chakeraloui2@yahoo.fr   chakeraloui2@yahoo.fr tunis, 2092, tunisia   216980348(Phone) 216980348(Fax) www;fsegt.rnu.tn Second Author: Ben hamida Hela miss FDSEPS benhamida_hela@yahoo.fr   tunis, 2092, tunisia   22489708(Phone)   fdspe.rnu.tn