Constructive Dialogue Management: cooperation based on communicative principles

When considering di erent dialogue systems, three approaches to dialogue management can be distinguished. Special purpose NL interfaces aim at providing an appropriate service with simple dialogues constrained by the requirements of a particular task. Usually the system reacts mechanically to the user's request, and the user is required to nd an appropriate question strategy to get the information she wants. Many information retrieval systems (library catalogues, ight information, tourist information) are of this type. The second approach aims at building conversing dialogue systems which allow active dialogue partners to engage in mixed initiative dialogues. This presupposes the modelling of realistic conversational settings, and thus requires explicit representation of the speakers' beliefs, goals and plans, as well as characterisation of appropriate dialogue behaviour by conversational roles. HAM-ANS [16] and KAMP [2] were early systems in this line, PEA [14] and EDGE [4] are recent examples.