Ron Petrick's Webpages

Workshop talk

Dialogue as Planning with Knowledge and Sensing, R. Petrick, slides from a talk presented at the Workshop on Situated Understanding of Intention, University of Pennsylvania, Philadelphia, USA, 2009-07-23.

[ slides ]


The problem of planning a sequence of dialogue moves---and hence the problem of recognising the intention behind partially-observable sequences of dialogue actions---can be viewed as an instance of the more general AI problem of planning with incomplete information and sensing. In contrast to "classical" planning actions, which model changes to the state of the world, sensing actions change the knowledge state of the agent while leaving the world state unchanged. As a result, such actions complicate the traditional planning process: sensing actions give rise to large or potentially infinite state spaces, and require a planner that can reason about its knowledge state as distinct from the world state.

This talk gives an overview of PKS (Planning with Knowledge and Sensing), a conditional planner that can generate plans with sensing actions and incomplete information [Petrick & Bacchus 2002, 2004]. Unlike traditional planners, PKS operates at the "knowledge level", by reasoning about the knowledge state, rather than the world state. PKS also supports features like functions, run-time variables, and program-like constructs, as part of its action-representation. Using recent results from the knowledge representation and planning communities, this talk presents a series of extensions to PKS, with the goal of adapting PKS to speech act-based dialogue planning. This talk also describes the role of PKS in PACO-PLUS, an investigation of interacting perception, action, and cognition in robot systems, illustrating how the same underlying techniques for ordinary action planning in robot domains transfer to dialogue planning.

This talk describes joint work with M. Steedman.