Consistent dialogue across concurrent topics based on an expert system model

There have been many working spoken dialogue systems, but very few of them are able to handle concurrent topics consistently if the user freely surfs among different topics at any time, because it is really difficult to resolve semantic ambiguities and check the knowledge consistencies among correlated topics. The issues include not only how to handle the information across multiple topics and domains with shared slots, but how to infer a reasonable dialogue state considering the new information or inconsistencies among knowledge structures after some correlated topics are activated. In this paper, a plan-based dialogue control mechanism that is capable of handling the very complicated dialogue problem is proposed. This mechanism can keep the knowledge consistent among multiple topics and domains when the topic is switched. Also, by representing the problem-solving procedures of different goals as loadable trees, the dialogue strategies are easy to maintain and modify, and can be dynamically adapted to the users during the dialogue.