Ontology Access in Grids with WS-DAIOnt and the RDF(S) Realization Semantic Grid Workshop GGF16, Athens, 15th Feb 2006 Ontology Engineering Group, UPM Miguel Esteban Gutiérrez Asunción Gómez-Pérez Óscar Muñoz García Boris Villazón Terrazas

2 GGF16, Athens, 15th Feb 2006 Table of Contents  OGSA-DAI limitations  WS-DAIOnt  Goals  Approaches  WS-DAI-RDF(S)  Component Description  Implementation details  Short demo  Workplan

3 GGF16, Athens, 15th Feb 2006 Definitions of Ontologies “An ontology is a formal, explicit specification of a shared conceptualization” Lightweight Ontologies : Include Concepts with properties, relations and Taxonomies Do not include Axioms and constraints. Heavyweight Ontologies : Include all the components Excellent!! If they have a lot of axioms.

4 GGF16, Athens, 15th Feb 2006 Diversity of Ontology tools and languages 1.No uniform access to ontologies implemented in W3C languages RDF(S) OWL 2.Each language has several query languages and inference engines RDF(S): SparQL, SeRQL, RQL, RDQL and SILRI, RIL, Triple OLW: OWL-QL and FACT, Racer 3. Each ontology tool and storage system has its own API for accessing ontologies Accessing RDF(S) ontologies Sesame Statements(classUri, rdfs:type, rdfs:class) next() getObject() Jena getResource(classURI)

5 GGF16, Athens, 15th Feb 2006 OGSA-DAI limitation  No Grid compliant ontology access mechanisms in RDF(S) and OWL  No specialized registry for localizing ontologies  No Grid compliant instance access mechanisms in RDF  SemGrid Applications access ontologies as on the Semantic Web

6 GGF16, Athens, 15th Feb 2006 OGSA-Ont  Grid compliant ontology access mechanisms  RDF(S)  OWL  Specialized registry for localizing ontologies

7 GGF16, Athens, 15th Feb 2006 Ontologies and S-OGSA Architect, adapt and extend existing ontology services to be Grid compliant  Access heterogeneus and distributed ontology sources as a homogeneous logical resources  Provide homogeneous service interfaces  Modular design to ease extensibility Insurance settlement Is -a Middleware layer Application layer Satellite quality analysis

8 GGF16, Athens, 15th Feb 2006 What is WS-DAIOnt?  Web Services Data Access and Integration – The Ontology Realization  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...  First implementation of WS-DAIOnt-RDF(S)  Backend: Sesame and SeRQL as query language  Download it from the OntoGrid web site (

9 GGF16, Athens, 15th Feb 2006 Four approaches for WS-DAIOnt Monolithic approach Dual tier approach Metamodel approach Declarative approach Low extensibility and adaptability High extensibility and adaptability Sesame Jena Dual tier approach Sesame Jena Monolithic approach

10 GGF16, Athens, 15th Feb 2006 Two sample implementations: Architectural implications Monolithic approach: Client side: splitted ontology access logic Server side: Two protocols + two implementations Dual tier approach: Client side: single access logic Server side: One protocol + two implementations

11 GGF16, Athens, 15th Feb 2006 RDFS model

12 GGF16, Athens, 15th Feb 2006 Component Description Jena....

13 GGF16, Athens, 15th Feb 2006 RDFSRepositorySelectorService

14 GGF16, Athens, 15th Feb 2006 RDFSRepositorySelectorService getRepositoryFactory message Returns a EPR for a given repository

15 GGF16, Athens, 15th Feb 2006 RDFSRepositoryService

16 GGF16, Athens, 15th Feb 2006 RDFSRepositoryService getClassFactory message Returns the EPR for a given class

17 GGF16, Athens, 15th Feb 2006 RDFSClassService

18 GGF16, Athens, 15th Feb 2006 RDFSClassService getSubclasses message Returns all the subclasses of a given class

19 GGF16, Athens, 15th Feb 2006 RDFSClassService getSuperClasses message Returns all the superclasses of a given class

20 GGF16, Athens, 15th Feb 2006 The rest of the model 1 2 3

21 GGF16, Athens, 15th Feb 2006 RDFSRepository.rdfs Structure RDFSRepository RDFSSesameRepository RDFSSesameFileRepository file RDFSSesameMemoryRepositoryRDFSSesameRemoteRepository user password RDFSSesameHTTPRepository url RDFSSesameRMIRepository rmiuri RDFSNamespace uri has SC More RDF(S) Repositories here to be added For example:RDFSJenaRepository Configuration

22 GGF16, Athens, 15th Feb 2006 RDFSRepository.rdf example <rdf:Description rdf:about=" A testing file civil_file <rdfs_repos:has rdf:resource=" /etc/ws-daio-rdfs/Civil_Personality.rdfs <rdf:type rdf:resource=" An example namespace. civil <rdf:type rdf:resource=" Configuration

23 GGF16, Athens, 15th Feb 2006 Ongoing development workplan  First spec for WS-DAIOnt  Ontogrid deliverable d3.1  WS-DAIOnt-RDF(S) implementation  access to RDF(S) ontologies…  … stored in Sesame (download it !!)  … stored in Jena (July 2006)  Spec at the end of (April 2006)  WS-DAIOnt-OWL  spec & first implementation (December 2006)  Provide seamless access to both RDF(S) and OWL (Aug. 07)

24 GGF16, Athens, 15th Feb 2006 Use WS-DAIOnt-RDF(S)! available at: Feedback to: Acknowledgements to the consortium