1 / 14

DAML+OIL: an Ontology Language for the Semantic Web

DAML+OIL: an Ontology Language for the Semantic Web. DAML+OIL Design Objectives. Well designed Intuitive to (human) users Adequate expressive power Support machine understanding/reasoning Well defined Clearly specified syntax (obviously) Formal semantics (equally important)

lacey
Télécharger la présentation

DAML+OIL: an Ontology Language for the Semantic Web

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. DAML+OIL: an Ontology Language for the Semantic Web

  2. DAML+OIL Design Objectives • Well designed • Intuitive to (human) users • Adequate expressive power • Support machine understanding/reasoning • Well defined • Clearly specified syntax (obviously) • Formal semantics (equally important) • Extend existing web standards • DAML+OIL is built on top of RDF(S)

  3. Why Build on RDF • Provides basic ontological primitives • Classes and relations (properties) • Class (and property) hierarchy • Can exploit existing RDF infrastructure • Provides mechanism for using ontologies • RDF triples assert facts about resources • Use vocabulary from DAML+OIL ontologies

  4. DAML+OIL DC PICS XHTML SMIL RDF(S) HTML XML The Cake!

  5. Why RDF Is Not Enough • Expressive inadequacy • Only range/domain constraints (on properties) • No properties of properties (unique, transitive, inverse etc.) • No equivalence, disjointness, coverings etc. • No necessary and sufficient conditions (for class membership) • Poorly (un) defined semantics

  6. How DAML+OIL Builds ON RDFS (1) • Extends expressive power • Constraints (restrictions) on properties of classes (existential/universal/cardinality) • Boolean combinations of classes and restrictions • Equivalence, disjointness, coverings • Necessary and sufficient conditions • Constraints on properties

  7. How DAML+OIL Builds ON RDFS (2) • Provides well defined semantics • Meaning of DAML+OIL statements is formally specified • Both model theoretic and axiomatic specifations provided • Allows for machine understanding and automated reasoning

  8. DAML+OIL  RDF • DAML+OIL ontology is a set of RDF statements • DAML+OIL defines semantics for certain statements • Does NOT restrict what can be said • Ontology can include arbitrary RDF • But no semantics for non-DAML+OIL statements

  9. Well Designed(?) • Intuitive to (human) users • Supports common ontological idioms • Adequate expressive power • Extends RDF in several directions • Support for machine understanding/reasoning • Designed to be “implementable” • No features for which it is difficult or impossible to define clear semantics (e.g., defaults) • Decidable and (empirically) tractable reasoning

  10. Why Automated Reasoning? • Semantic web requires machine understanding (of resource descriptions) • Reasoning is integral to understanding • Supports design and use of ontologies • Checking class consistency (e.g., Skyscraper) • Checking/deriving subClassOf hierarchy • Particularly useful when ontologies are large, multi-authored and rapidly evolving • Also useful when integrating/sharing ontologies • Does not tell us how to deal with inconsistencies • But we should be able to determine when they exist

  11. Extending DAML+OIL • Work in progress on Datatypes • Plan to support (some of) XMLS datatypes • Datatypes will be disjoint from “abstract” classes and only accessible via properties • Maintains “implementability” of language • Further extensions in new language layers • E.g., DAML-RULES • Layers will use DAML+OIL as it uses RDF

  12. New Language Layers DAML-??? DAML+OIL DC PICS XHTML SMIL RDF(S) HTML XML

  13. DAML+OIL Infrastructure • Can exploit existing RDF tools/services • Ontology editors being built/adapted • OilEd (Manchester) • Protégé (Stanford) • OntoEdit (Karlsruhe) • Ontology integration tools being built/adapted • Chimera (Stanford) • Reasoning services • DL derived reasoners, e.g., FaCT (used by OilEd) • Rule based reasoners, e.g. SiLri (Karlsruhe) • Markup tools • Additional tools/infrastructure urgently required

  14. DAML+OIL Summary • Ontology language for Semantic Web • Extends RDF • More expressive power • Well defined semantics • Implementable • Decidable and tractable reasoning • Cost is some restriction on expressive power • Extensible • Cost may be loss of (some of) above properties

More Related