  To appear in Theory and Practice of Logic Programming (TPLP), 2008.
  We are researching the interaction between the rule and the ontology layers
of the Semantic Web, by comparing two options: 1) using OWL and its rule
extension SWRL to develop an integrated ontology/rule language, and 2) layering
rules on top of an ontology with RuleML and OWL. Toward this end, we are
developing the SWORIER system, which enables efficient automated reasoning on
ontologies and rules, by translating all of them into Prolog and adding a set
of general rules that properly capture the semantics of OWL. We have also
enabled the user to make dynamic changes on the fly, at run time. This work
addresses several of the concerns expressed in previous work, such as negation,
complementary classes, disjunctive heads, and cardinality, and it discusses
alternative approaches for dealing with inconsistencies in the knowledge base.
In addition, for efficiency, we implemented techniques called
extensionalization, avoiding reanalysis, and code minimization.
