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WS-DAIOnt-RDF(S): RDF(S) Ontology Access. www.ontogrid.eu. Oscar Corcho 1 , Miguel Esteban 2 1 University of Manchester, 2 Universidad Politécnica de Madrid. Primer Taller en Grid Computing Universidad del Valle, Cali, Colombia January 2007. Outline. Introduction and Motivation
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WS-DAIOnt-RDF(S): RDF(S) Ontology Access www.ontogrid.eu Oscar Corcho1, Miguel Esteban2 1University of Manchester, 2Universidad Politécnica de Madrid Primer Taller en Grid ComputingUniversidad del Valle, Cali, Colombia January 2007
Outline • Introduction and Motivation • Interface organization • Interface specification • Summary Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Motivation • Current Semantic Grid Applications access ontologies using Semantic Web technologies • No Grid compliant ontology access mechanisms for RDF(S) and OWL ontologies that exploit resource sharing capabilities • No specialized ontology registries • No Grid compliant instance access mechanisms in RDF Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
The RDF(S) Access Vision • What is all about? • Providing an access mechanism to RDF(S) data sources • Two different means for interacting: • Query access: using SPARQL • Ontology access: using ontological primitives based on the RDF(S) model • Alternative, but not exclusive! • Use each one according to your needs… Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
What is WS-DAIOnt? • Specification of Grid Compliant Ontology Services, which • Defines a framework for creating ontology access services in a Grid environment • Is fully compliant with S-OGSA (consequently with OGSA) • Is based on up-to-date Grid standards (GGF) • WS-DAI • Is based on Web Service standards (OASIS, W3C) • WS-RF, WS-Addressing... • Formal name • Web Services Data Access and Integration – The Ontology Realization Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Data access in OGSA • OGSA provides data access and integration services (DAIS) that are well suited for building the ontology access protocol • The DAIS are organized hierarchically with the WS-DAI specificiation on top and specific realizations below: • WS-DAI defines: • A set of patterns for defining messages, operations and interfaces • A set of basic properties for describing the services and associated resources capabilities • The realizations provide specialized access to well-defined resources Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
What is RDF(S)? • RDF(S) = RDF + RDFS • RDF: Resource Description Framework • A framework for representing information in the Web • Framework = Built-in vocabulary (Abstract Syntax) + Entailment Rules (Formal Semantics) • RDFS: Resource Description Framework Schema • A RDF vocabulary for building RDF vocabularies • W3C Standards since Feb 2004 Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Outline • Introduction and Motivation • Interface organization • Interface specification • Summary Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface organization • Two layers: • Bulk access • Specialized access • Interface types: • Native interfaces: mimic classes of the RDF(S) data model • Utility interfaces: provide additional functionalities that enhance usability • Message definition: • Direct data access: • Retrieval of directly associated information • Creation of new data (including attachments) • Deletion of existing data (including detachments) • Indirect data access • Delegation of access to services that provide specialized access to a subset of associated information Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
WS-DAIOnt-RDF(S) Implementation Architecture • Web Services Data Access and Integration – The Ontology Realization • First implementation focused on RDF(S): WS-DAIOnt-RDF(S) • Sesame and Jena • Future: Oracle RDF-store • Query languages: SPARQL, SeRQL, RDQL, RQL • Two-tier architecture • Web Service tier • Upper service layer • Intermediate service layer • Lower service layer • RDF(S) access tier • RDFSConnector • Storage layer Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Implementation and Specification Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Where we are moving to… Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Outline • Introduction and Motivation • Interface organization • Interface specification • Summary Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (I)Repository Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (II) RepositoryFactory Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (III) Resource Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (IV)Class Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (V)Property Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (VI)Statement Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (VII)List Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (VIII)ListFactory Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (IX)Container Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (X)ContainerFactory Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (XI)ContainerIterator Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Interface specification (XII)Alt Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Outline • Introduction and Motivation • Interface organization • Interface specification • Summary Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007
Summary • Ontology-based access operations • Provided interfaces that, • Mimic main classes of the data model, or • Abstract useful functionalities that enhance usability • Followed object-oriented principles • Some figures: • 12 interfaces provided • 125 operations available • 18 faults defined Primer Taller en Grid Computing. Universidad del Valle, Cali, Colombia. January 2007