A script-based approach to modifying knowledge bases

Modifying knowledge-based systems (KBSs) is a complex activity. One of its di-culties is that several related portions of the KBS might havetobechanged in order to maintain the coherence of the system. However, it is di cult for users to gure out what has to be changed and how. This paper presents a novel approach for building knowledge acquisition (KA) tools that overcomes some of the limitations of current approaches. In this approach, knowledge of prototypical procedures for modifying KBSs is used to guide users in changing all related portions of a KBS. These procedures, which we call knowledge acquisition scripts (or KA Scripts), capture how related portions of a KBS can be changed coordinately. By using KA scripts, a KA tool would be able to relate individual changes in di erent parts of a KBS, enabling the analysis of each individual change from the perspective of the overall modi cation. The paper also describes the implementation of ETM: a script-based tool that builds on the EXPECT framework for building KBSs ([Gil, 1994]), discusses how wehave addressed some important issues of this approach, and describes a preliminary empirical evaluation of ETM that shows that KA Scripts allow users to perform KBSs modi cation tasks more e ciently.