Modeling Dialogue By Functional Sub Categorization

In this paper we present a dialogue model which has as its main goat to place in context the utterance generated by the speaker. The dialogue model considers that an intervention generates one or more ilocutive acts which are handled as flmctions. These functions subcategorize to or are subcategorized by other functions in the dialogue. The model uses an exchange schema with the purpose of expressing the different ftmctional subcategorizations. These schemas have properties close to the semantic forms of the verbs in a lexical-functional context. 1 INTRODUCTION In task-orientetl dialogues two speakers work in cooperation with the purpose of carrying out a plan. This type of interaction has a start and a development structured by the restrictions of space, thne, transaction object and role of the partieipanls. Carberry, 9211 have suggested that a coherent discourse consists of segments that are related to one another through some type of structuring relation. Our dialogue model tries to capture the goal-oriented nature of discourse, ideutifing the discourse structure by providing the details of a computational mechanism for recognizing the structural relationships. The model enables the incremental recognition of communicative goals using rewriting rules and functional equations. The grammar constructs the structural tree captnring the dialogical functions of the discourse using functional snbcategorization. The subcategorization process improves on previous approaches [Ferrary et al., 88; Bilage, 91; JOnsson, 911, increasing the expresive power of the traditional dialogue models by modeling the relationships among the communicative actions enabling the task of connecting discottr~. The different parts of the system have been implemented using a blackboard architecture. The process starts obUfining the f-slructure associated to the intervention making use of a lexical-functional grammar [Abaitua ct al., 9111. In a second phase the f-structure is refined providing the correct explanation, essentially it solves the verbal interpretation and obtains referential information. Then, the planner and/or the dialogue module suu't to work. In the remainder of this paper, we will present our dialogue model in a top-down manner. Firstly, we show the exchange structure attoptexl and the subcategorization process using two samples. Then, we explain the retroactive and proactive nature of the interaction and we conclude by presenting two kinds of special interventions, the complex ~lll(l compound interventions. 2 EXCIIANGE STRUCTURE We assign to the constituents of the exchange level initiative and reactive ilocutive functions. These functions qualify ctmstituents which are in the same level of structuration. The initiative …