Relational Database Integration with RDF/OWL(About) Using the W3C OWL ontology standard lets you get more out of all kinds of data. Find out how this standard and some free software lets you query two databases as if they were one.
The primary goal of this article is to put together a demonstration of how you can use OWL to integrate two relational databases, and then perform queries against the aggregate collection to answer realistic questions that you could not answer without the addition of an OWL ontology.
Structured Ontology Format(About) Rob Shearer The University of Manchester
(nice demo of an ajax script at OWLED 2007)
Abstract. This paper presents a simple data model for the representation
of OWL ontologies (including the new features of OWL 1.1). The
model is built from basic structures native to all common programming
environments, so it can be used directly as an API for ontology analysis
and manipulation. Furthermore, serialization of these structures using
the widely-supported YAML standard yields a readable text format
suitable for ontology authoring by average users with text editors and
Horst, Herman J. ter: Completeness, decidability and complexity of entailment for RDF Schema and a semantic extension involving the OWL vocabulary(About) We prove that entailment for RDFS (RDF Schema) is decidable, NP-complete, and in P if the target graph does not contain blank nodes.We show that the standard set of entailment rules for RDFS is incomplete and that this can be corrected by allowing blank nodes in predicate position. We define semantic extensions of RDFS that involve datatypes and a subset of the OWL vocabulary that includes the property-related vocabulary (e.g. Functional- Property), the comparisons (e.g. sameAs and differentFrom) and the value restrictions (e.g. allValuesFrom). These semantic extensions are in line with the 'if-semantics' of RDFS and weaker than the 'iff-semantics' of D-entailment and OWL (DL or Full). For these semantic extensions we present entailment rules, prove completeness results, prove that consistency is in P and that, just as for RDFS, entailment is NP-complete, and in P if the target graph does not contain blank nodes. There are no restrictions on use to obtain decidability: classes can be used as instances.
On the properties of metamodeling in OWL(About) Abstract: A common practice in conceptual modeling is to separate the intensional from the extensional model. Although very intuitive, this approach is inadequate for many complex domains, where the borderline between the two models is not clear-cut. Therefore, OWL-Full, the most expressive of the Semantic Web ontology languages, allows combining the intensional and the extensional model by a feature we refer to as metamodeling. In this paper, we show that the semantics of metamodeling adopted in OWL-Full leads to undecidability of basic inference problems, due to free mixing of logical and metalogical symbols. Based on this result, we propose two alternative semantics for metamodeling: the contextual and the HiLog semantics. We show that SHOIQ— a description logic underlying OWL-DL— extended with metamodeling under either semantics is decidable. Finally, we show how the latter semantics can be used in practice to axiomatize the logical interaction between concepts and metaconcepts.
Eagle is a type of RedListSpecies. Thus, RedListSpecies acts as a
metaconcept for Eagle
The examples such as the one given above are often dismissed with an argument that “eagle as a species” and “eagle as a set of all individual eagles”
are not the one and the same thing, and should not be referred to using the
same symbol...we simply observe that the word “eagle” in most people’s minds invokes a notion of a “mighty bird of prey.” The interpretation of
this notion as a concept or as an individual is secondary and is often context-dependent, so using different symbols for the same intuitive notion makes the
model unnecessarily complex.
alphaWorks : IBM Web Ontology Manager(About) IBM Web Ontology Manager is a lightweight, Web-based tool for managing ontologies expressed in Web Ontology Language (OWL). With this technology, users can browse, search, and submit ontologies to an ontology repository. This technology includes a Web interface for easy uploading of ontologies in an .owl format by any user of the system. It also includes an interface for generating (using Jastor) Java™ APIs from uploaded ontology files.
IBM Web Ontology Manager differs from IBM Ontology Management System (a former alphaWorks technology, now merged into the IBM Integrated Ontology Development Toolkit) in that it does not include a statement repository. Instead, based on the ontologies visible to the system, it can generate Java classes for accessing any Jena-compatible RDF statement repository.