[1] Univ Florence, CNIT Natl Interuniv Consortium Telecommun, MICC Media Integrat & Commun Ctr, Florence, Italy
[2] Nimes Univ, CNRS, LIRMM, UMR5506, Nimes, France
[3] Charles Sturt Univ, Sch Comp & Math, Bathurst, NSW, Australia
[4] Univ Florence, MICC Media Integrat & Commun Ctr, Florence, Italy