Goal-directed reasoning with ACE-SSM

Abstract

Past research shows that the goal of knowledge-based systems (KBSs) is not only to produce a solution to a problem situation they face, but also to construct, implicitly or explicitly, a situationspecific model (SSM) that explicates the rationale behind that solution. This paper focuses on how KBSs can benefit from the availability of explicit goal knowledge that reflects the underlying structure (ontology) of SSMs constructed for an application task. It first shows how goal knowledge can be captured. Then, it explains how ACE-SSM-an architecture for constructing explicit SSMs-uses this knowledge to direct the construction of explicit SSMs. Finally, it discusses benefits that KBSs can derive from the availability of explicit SSMs and their underlying goal knowledge. Some of these benefits pertain to ways to simplify the construction and maintenance of KBSs through reuse, while others have to do with ways to endow KBSs with more robust problem-solving and explanation capabilities. These benefits are illustrated using concrete examples.

Knowledge modeling directed by situation-specific models

“…More specifically, in SSM-DKM, because the notion of an SSM defines the what facet, an SSM is a central structure that drives the modeling of other facets. As we showed here and elsewhere (Benaroch, 1998), modeling the what facet explicitly facilitates the 148 construction of explicit SSMs as well as permits the modeling of the how facet in declarative terms.…”

“…These constructs are supposed to interact with ACE-SSM-a KBS architecture that creates explicit SSMs using the above discussed reasoning process (Benaroch, 1998).…”

“…An explicit SSM can serve as a working memory because it constitutes a complete trace of what a KBS did to produce final and intermediate inference results in the course of solving a specific problem situation. As such, an explicit SSM permits the KBS that creates it to explain the solutions it embeds, explain the problem-solving behavior that produced these solutions and dynamically reflect on this behavior during problem solving (Clancey, 1992;Benaroch, 1998). identified a related source of value from the ability to create explicit SSMs.…”

“…He explains that KBS architectures that support the process of problem solving as modeling by constructing explicit SSMs could reflect more of the real nature of problem-solving from a knowledge-level perspective. One architecture for constructing explicit SSMs is ACE-SSM (Benaroch, 1998). ACE-SSM centers its reasoning around goal knowledge reflecting the ontology, or underlying structure, of SSMs that an application task aims to produce.…”

“…Second, the model captures strategic (or problem-solving) knowledge in declarative terms pertaining to the ontology of SSMs created for the task. Both these beneficial traits have been illustrated in the context of ACE-SSM, a KBS architecture that constructs explicit SSMs (Benaroch, 1998). …”