Type-based Human-Computer Interaction
Peter Ljunglöf · 2013
A dialogue system is a computer system that can engage in dialogue with a human in order to complete tasks such as answering questions or performing actions. The information state update (ISU) approach [2] is a linguistically motivated theory of how to design dialogue systems. The approach is capable of advanced dialogue behaviour, and is based on a structured information state to keep track of dialogue context information. The underlying logic of ISU-based systems tend to get very complicated, making it difficult to foresee the side effects of changing, adding or deleting inference rules. Ranta and Cooper [5] describe how a dialogue system can be implemented in a syntactical proof assistant based on type theory. Metavariables in the proof tree represent questions that needs to be answered by the user so that the system can calculate a final answer. However, the backbone of their theory is a very simple form-based dialogue system that cannot handle underspecified answers, anaphoric expressions, or ambiguous utterances. In [3], we extended their theory with ideas from ISU and Dynamic Syntax [1], to make the system handle more flexible dialogues. Ranta and Cooper use focus nodes to know which of the nodes in the tree that is the current question under discussion. To this we add the idea