Goal-Oriented Multimedia Dialogue with Variable Initiative

A dialogue algorithm is described that executes Prolog-style rules in an attempt to achieve a goal. The algorithm selects paths in the proof in an attempt to achieve success and proves subgoals on the basis of internally available information where possible. Where \missing axioms" are discovered, the algorithm interacts with the user to solve subgoals, and it uses the received information from the user to attempt to complete the proof. A multimedia grammar codes messages sent to and received from the user into a combination of speech, text, and voice tokens. This theory is the result of a series of dialog projects implemented in our laboratory. These will be described including statistics that measure their levels of success. When two individuals collaborate to solve a problem, they undertake a variety of behaviors to enable a fast and eecient convergence to a goal. They reason individually to nd a sequence of actions that will achieve success and if they are successful, the problem will be solved directly. The reasoning, however, could uncover obstacles and they may then communicate to try to address them. One participant may see a solution to the problem if a speciic issue can be solved and bring that to the attention of the other. The other may be able to provide the needed support but may respond with other subproblems to be faced. They hand back and forth subproblems related to the global goal and solutions to them as they nd them. If a suucient set of the subgoals is solved, the global one will be solved also and the interaction will terminate with success. The problematic subgoals are thus the ones that generate most interactions. We will call the set of interactions related to a given subgoal a subdialogue, and every problem solving dialogue seems to be an amalgamation of such sub-dialogues. Thus we do not see a problem solving dialogue as a linear coverage from beginning to end. Rather we see it as a light footed dance in the space of mentionable topics with almost every step aimed at a problematic subgoal. The concept of subdialogues as constituents of dialogue has been studied widely. For example, Grosz and Sidner 5] call them segments and they give an analysis of dialogue phenomena in terms of a three part model. Speciically, they deene the intentional structure to be the reasoning mechanism that supports the interaction, the attentional …