Proceedings of the 15th Workshop on the Semantics and Pragmatics of Dialogue - Front Matter Ron Artstein author Mark Core author David DeVault author Kallirroi Georgila author Elsi Kaiser author Amanda Stent author 2011-09 SEMDIAL Los Angeles, California text conference publication semdial-2011-semantics http://semdial.org/anthology/semdial2011_londonlogue_front_matter.pdf