Semanlink - OWL AND Description Logic

SKOS Now Interoperates with OWL 2 | AI3:::Adaptive Information

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2013-02-07 About

Structured Objects in OWL: Representation and Reasoning. In Proc. of the 17th Int. World Wide Web Conference (WWW 2008), Beijing

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Very good presentation at WWW 2008. Nominated for the best paper award<br/>
Abstract: Applications of semantic technologies often require the representation of and reasoning with structured objects—that is, objects composed of parts connected in complex ways. Although OWL is a general and powerful language, its class descriptions and axioms cannot be used to describe arbitrarily connected structures. An OWL representation of structured objects can thus be underconstrained, which reduces the inferences that can be drawn and causes performance problems in reasoning. To address these problems, we extend OWL with description graphs, which allow for the description of structured objects in a simple and precise way. To represent conditional aspects of the domain, we also allow for SWRL-like rules over description graphs. Based on an observation about the nature of structured objects, we ensure decidability of our formalism. We also present a hypertableau-based decision procedure, which we implemented in the HermiT reasoner. To evaluate its performance, we have extracted description graphs from the GALEN and FMA ontologies, classified them successfully, and even detected a modeling error in GALEN.

2008-04-23 About

CO-ODE

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2007-07-26 About

On the properties of metamodeling in OWL

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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.
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Eagle is a type of RedListSpecies. Thus, RedListSpecies acts as a
metaconcept for Eagle
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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.

2006-12-01 About