F-OWL is an ontology inference engine for the Web
Ontology Language OWL. The ontology inference mechanism in F-OWL is
implemented using Flora-2,
an object-oriented knowledge base language and application development
platform that translates a unified language of F-logic, HiLog, and Transaction
Logic into the XSB deductive
engine. Key features of F-OWL include the ability to reason with the ontology
model defined by the latest standard OWL language recommended by the W3C,
the ability to support knowledge consistency checking using axiomatic
rules defined in Flora-2, and an open application programming interface
(API) for Java application integrations.
The latest release of F-OWL (v0.3) has been used as the
ontology reasoner in a number of different intelligent system prototypes,
a broker-centric agent architecture for pervasive context-aware systems,
TAGA a multi-agent system for e-commerce
trading simulation, and REI
a policy-based security system for distributed trust management.
The use of an object-oriented rule based language (i.e.,
Flora-2) in an advanced Prolog logic programming system (i.e., XSB) differentiates
the implementation of F-OWL from other ontology inference engines such
as JTP, RACER and DAMLJessKB.
- F-OWL exploits a special rule evaluation mechanism called tabling,
provided by the underlying XSB system. This mechanism can facilitate
result caching in the backward chaining reasoning, which is beyond the
capability of a traditional Prolog system. As ontology reasoning often
involves repetitive evaluation of some closed-world domain knowledge,
the tabling mechanism can help to avoid repetitive ontology inference
calculations, improving the overall system performance.
- In contrast to the use of conventional logic languages in other ontology
inference engines (e.g., KIF in JTP and CLIPS in DAMLJessKB), F-OWL
adopts an object-oriented language Flora-2 that has a closer language
constructs to the OWL language (e.g., both Flora-2 and OWL support the
representations of classes, properties, restrictions, and instants).
- Building F-OWL on an advanced logic programming system creates the
potential for applications to be integrated and interoperate with other
intelligent systems (e.g., integrating an existing planning system to
exploit knowledge inferred from an existing ontology model).
F-OWL is still in its early stage of development.
It's a joint work between a group of PhD students Harry
Kagal and their advisor Tim