MAKING THE KNOWLEDGE-BASE SYSTEMS MORE EFFICIENT - A METHOD TO DETECTINCONSISTENT QUERIES

The processing cost of queries with an empty answer, both in the datab ase and knowledge base context, is usually high. One purpose of semant ic query optimization methods in the database context is to use semant ic knowledge to detect such types of queries. Although semantic query optimization is well known in the database context, this is not the ca se for knowledge base systems (KBS's). This paper presents a method th at allows the detection of queries with an empty answer using only sem antic information expressed in the knowledge base definition. The meth od can be applied in the context of KBS's that provide some of the fol lowing features: structuring mechanisms, assertional knowledge, tempor al information, and handling of inequality expressions.