Metadata Metadata Representation, Representation, Knowledge Knowledge Representation, and Representation, and Ontologies SectionOntologies Section

Line PouchardLine Pouchard

Oak Ridge National Oak Ridge National LaboratoryLaboratory

What makes the Semantic Grid What makes the Semantic Grid different from the Semantic different from the Semantic Web (according to Line)Web (according to Line) SG is focused on the needs of SG is focused on the needs of

applications that use Grid technologies applications that use Grid technologies in various context. in various context.

These tend to be scientific applications These tend to be scientific applications from scientific domains whose needs from scientific domains whose needs are quite different from those of are quite different from those of typical web users. But they all use the typical web users. But they all use the Web in various clunky, home grown Web in various clunky, home grown packages. packages.

So the SG is focused on developing So the SG is focused on developing bridges, leveraging and cross-cutting bridges, leveraging and cross-cutting technologies from the SW and assess technologies from the SW and assess them for scientific applications.them for scientific applications.

DriversDrivers (Line and Jim)(Line and Jim)

Need to share context-dependent data across Need to share context-dependent data across community(ies) (data dissemination/discovery)community(ies) (data dissemination/discovery)

Support mapping between data models Support mapping between data models (across domains, over time) (across domains, over time)

Managing non-hierarchical data relationships / Managing non-hierarchical data relationships / multiple hierarchies at oncemultiple hierarchies at once

Describing hypothesis/statements of trust Describing hypothesis/statements of trust /reification (statements about other /reification (statements about other statements)statements)

Numerous XML schemas and DTDs, most are Numerous XML schemas and DTDs, most are domain, or even application specific. domain, or even application specific.

More driversMore drivers

Mechanisms for re-use, mediation, Mechanisms for re-use, mediation, aggregation, semantic federation are aggregation, semantic federation are needed.needed.

Needs for ontology repositories, discovery Needs for ontology repositories, discovery and capturing toolsand capturing tools

Granularity of ontologiesGranularity of ontologies Applying semantic stuff to large Applying semantic stuff to large

data/complex workflow/distributed data/complex workflow/distributed independent contributorsindependent contributors

Maintaining links between data and Maintaining links between data and ontologies, evolving schemas, …ontologies, evolving schemas, …

LanguagesLanguages

RDF, RDFS, OWL descriptions:RDF, RDFS, OWL descriptions:

gather in one place a description of gather in one place a description of the characteristics of each languagethe characteristics of each language

comparison, comparison, including when to use including when to use each. Some of this already exists each. Some of this already exists but needs updating and gathering. but needs updating and gathering.

For instance, For instance,

More on languagesMore on languages

Collection of assertions and triples, propertiesCollection of assertions and triples, properties Range and domain of the triplesRange and domain of the triples EquivalencesEquivalences BooleansBooleans Restrictions on classes and propertiesRestrictions on classes and properties CardinalityCardinality class propertiesclass properties Other possible languagesOther possible languages (there are some!): (there are some!):

PSL, Ontolingua, KIF, etc..: what is suitable, not PSL, Ontolingua, KIF, etc..: what is suitable, not suitable for the semantic grid and why.suitable for the semantic grid and why.

Existing Grid technologies Existing Grid technologies that can potentially be that can potentially be enhanced by SG:enhanced by SG: These would include the ones that we These would include the ones that we

think are the most receptive to the think are the most receptive to the work performed on SG. work performed on SG.

It should make a clear case for why It should make a clear case for why each Grid technology presented here each Grid technology presented here would benefit from semantic grid would benefit from semantic grid technologies, for metadata and technologies, for metadata and knowledge representation, ontologies, knowledge representation, ontologies, etc…. and where. etc…. and where.

Here are just a few bullets:Here are just a few bullets:

Metadata Catalog ServicesMetadata Catalog Services OGSI service descriptionOGSI service description WS-Resource FrameworkWS-Resource Framework Data Format Description Data Format Description

LanguageLanguage