Organising Knowledge Refinement Operators

Knowledge re nement tools seek to correct faulty knowledge based systems (KBSs). The goal of theKrustWorks project is to provide a source of re nement components from which specialised re nement tools tailored to the needs of a range of KBSs can be built. Central to the toolkit is a set of generic re nement operators and a representation language for KBS rules. The language abstracts those properties of rule elements which determine whether they can take part in rule chaining, and how they can be re ned. It is used to organise the re nement operators so that each can be applied to similar rule elements found in di erent KBSs. This organisation facilitates the re-use of re nement operators when new KBSs are encountered, and the development of new ones. The toolkit was evaluated by applying it to a KBS shell signi cantly di erent from the ones previously encountered. The rule elements from this shell could be represented within the existing hierarchy, but it was necessary to add some new re nement operators. A KrustTool was then able to x bugs actually occurring in the application, which conrms the usefulness of the re nement operators, and of our approach to organising and applying them.