“…Models of this kind have been widely used for speech recognition and also for language understanding (Levin and Pieraccini, 1995), (Minker et al, 1999), (Segarra et al, 2002), (He and Young, 2003), (Esteve et al, 2003). Even though in the literature there are models for dialog managers that are manually designed, over the last few years, approaches using statistical models to represent the behavior of the dialog manager have also been developed (Levin et al, 2000), (Torres et al, 2003), , (Williams and Young, 2007). These approaches are usually based on modeling the different processes probabilistically and learning the parameters of the different statistical models from a dialog corpus.…”