Generating queries and replies during information-seeking interactions

Analysis of naturally occurring information-seeking dialogues indicates that they usually consist of a number of distinct discourse segments, such as a greeting segment, a request issued by a user, an optional clariication segment, a transfer of information segment, and a nal closing segment. The clariication interaction is often initiated by the information provider, and it may be due to one of the following reasons: (1) there is confusion regarding the user's intentions, (2) there is insuucient information to formulate a plan to satisfy a recognized intention, or (3) there is diiculty in formulating a plan that satisses a recognized intention. Once the information provider determines the user's intention and formulates a plan to achieve this intention, the information transfer phase is initiated to inform the user about the proposed plan. In this paper, we present a mechanism for generating queries during the clariication stage and answers during the information transfer stage. Given a hierarchical representation of the alternatives possibly intended by a user, and the probabilities of these alternatives, our mechanism determines the hierarchy level at which a query must be directed, and the query to be posed in order to determine the alternative intended by the user. Once the user's intentions are ascertained, the mechanism determines whether additional information is required and the manner in which queries may be posed to acquire this information. When a user's intentions cannot be satissed by means of a single plan, our mechanism enters into a negotiation process to alter the user's speciications until a valid plan is formulated. In the nal stages of the interaction, the mechanism determines the information to be transferred and generates an answer to eeect the transfer. The mechanisms for negotiation and for the generation of queries and answers described in this paper have been implemented in a system called radar, a computerized information providing system that functions as a travel agent.