Using the F2 OODBMS to support incremental knowledge acquisition

Ripple down rules (RDR) is an incremental knowledge acquisition (KA) methodology, where a knowledge base (KB) is constructed as a collection of rules with exceptions. Nested ripple down rules (NRDR) is an extension of this methodology which allows the expert to enter her/his own domain concepts and later refine these concepts hierarchically. In this paper we show similarities between incremental knowledge acquisition and database schema evolution, and propose to use the F2 object-oriented database management system (OODBMS) to implement an NRDR knowledge based system. We use the existing non-standard features of F2 and show how multiple instantiation and object migration (known as multiobjects feature in F2), and schema evolution capabilities in F2 easily accommodate all the update mechanisms required to incrementally build an NRDR KB. We illustrate our approach with a KA session.