https://hal.archives-ouvertes.fr/hal-01081273 Contributor : Taoues LahremConnect in order to contact the contributor Submitted on : Friday, November 7, 2014 - 3:58:54 PM Last modification on : Tuesday, February 18, 2020 - 12:12:36 PM Long-term archiving on: : Friday, April 14, 2017 - 12:22:02 PM