The Representation and Use of Focus in a System for Understanding Dialogs

As a d ia log progresses the objects and ac t ions that are most re levant to the conversat ion, and hence in the focus of a t t e n t i o n of the d ia log p a r t i c i p a n t s , change. This paper describes a representa t ion of focus for language understanding systems, emphasizing i t s use in understanding taskor ien ted d ia logs . The representat ion h i g h l i g h t s tha t par t of the knowledge base re levant at a given po in t in a d i a l o g . A model of the task is used both to s t ruc tu re the focus representat ion and to provide an index i n t o p o t e n t i a l l y re levant concepts in the knowledge base The use of the focus representa t ion to make r e t r i e v a l of items from the knowledge base more e f f i c i e n t is described.