Formulating diagnostic problem solving using an action language
with narratives and sensing
Chitta Baral, Sheila McIlraith, and Tran Cao Son
Abstract
Given a system and unexpected observations about the system, a
diagnosis is often viewed as a fault assignment to the various
components of the system which is consistent with (or which explains)
the observations. If the observations occur over time, and if we
allow the occurrence of (deliberate) actions and (exogenous) events,
then the traditional notion of a candidate diagnosis must be modified
to consider the {\em possible occurrence of actions} and events
that could account for the unexpected system behavior.
In the presence of multiple candidate diagnoses, we may need to
perform actions and observe their impact on the system, to be able to
narrow the list of possible diagnoses, and possibly even initiate some
repair. A plan that guarantees such narrowing will be referred to as a
{\em diagnostic plan}, and if this plan also guarantees that at the
end of the execution of the plan, the system has no faults then we
refer to it as a {\em repair plan}.
Since actions and narrative play a central role in diagnostic problem
solving, we characterize diagnosis, diagnostic planning and repair
with respect to the existing action language $\call$, extended to
include static constraints, sensing actions, and the notion of
observable fluents. This language is used to provide a uniform
account of diagnostic problem solving.