Perception in Multimodal Dialogue Systems [electronic resource] : 4th IEEE Tutorial and Research Workshop on Perception and Interactive Technologies for Speech-Based Systems, PIT 2008, Kloster Irsee, Germany, June 16-18, 2008. Proceedings / edited by Elisabeth André, Laila Dybkjær, Wolfgang Minker, Heiko Neumann, Roberto Pieraccini, Michael Weber.