KROL: A Knowledge Representation Object Language On Top Of Prolog

This paper presents a Knowledge Representation Object Language (KROL) on top of Prolog. KROL aimed at providing the ability to develop second-generation expert systems. The main aspects of KROL include multi-paradigm knowledge representation (first-order predicate logic, objects, rules), inference mechanisms at different levels of granularity, explanation facility, object-oriented database management module, and user-friendly interface. KROL has sufficient expressive power to be used in applying demanding knowledge-based modeling methodologies, such as KADS and Generic Task, which are the major landmarks of the second-generation expert systems technology. Four successful agricultural expert systems were developed in the last six years using KROL. To demonstrate the language capabilities, we present an example of disorder diagnosis.