W3C Model Based UI ’2008 –Mandelieu, October 24, 2008 UsiXML, a User Interface Model and Language Engineering approach Jean Vanderdonckt, Juan Manuel Gonzalez Calleros Université catholique de Louvain (UCL) Louvain School of Management (LSM) Information Systems Unit (ISYS) Belgian Laboratory of Computer-Human Interaction (BCHI) http://www.isys.ucl.ac.be/bchi