oil: an ontology infrastructure for the semantic web

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OIL: An Ontology Infrastructure for the Semantic Web D. Fensel, F. van Harmelen, I. Horrocks, D. L. McGuinness, P. F. Patel- Schneider Presenter: Cristina Nicolae

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OIL: An Ontology Infrastructure for the Semantic Web. D. Fensel, F. van Harmelen, I. Horrocks, D. L. McGuinness, P. F. Patel-Schneider Presenter: Cristina Nicolae. Ontologies. “An ontology is a formal , explicit specification of a shared conceptualization .” - PowerPoint PPT Presentation

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Page 1: OIL: An Ontology Infrastructure for the Semantic Web

OIL: An Ontology Infrastructure for the Semantic Web

D. Fensel, F. van Harmelen, I. Horrocks, D. L. McGuinness, P. F. Patel-Schneider

Presenter: Cristina Nicolae

Page 2: OIL: An Ontology Infrastructure for the Semantic Web

Ontologies

• “An ontology is a formal, explicit specification of a shared conceptualization.”– conceptualization: abstract model of some

phenomenon in the world that identifies that phenomenon’s relevant concepts

– explicit: the type of concepts used and the constraints on their use are explicitly defined

– formal: the ontology should be machine understandable

– shared: an ontology captures consensual knowledge (accepted by a group)

Page 3: OIL: An Ontology Infrastructure for the Semantic Web

Applications of ontology technology (1/3)• Knowledge management

– acquiring, maintaining and accessing an organization’s knowledge

– weaknesses:• searching information (irrelevant word in other context)• extracting information (lack commonsense knowledge)• maintaining (large sources)• automatic document generation (require a machine-

accessible representation of the semantics of info sources)

– future solution:• semantic annotations

Page 4: OIL: An Ontology Infrastructure for the Semantic Web

Applications of ontology technology (2/3)• Web commerce

– online stores, shopping agents, online marketplaces, auction houses

– get information from several stores through wrappers – which use keyword search to find product info

– limitations:• effort (writing wrapper for each online store is time-consuming +

changes in store)• quality (info extracted is limited, error-prone and incomplete)

– future solution:• software agents to understand product information

Page 5: OIL: An Ontology Infrastructure for the Semantic Web

Applications of ontology technology (3/3)• Electronic business

– e-commerce in business-to-business field– protocol (standard): the UN Edifact– shortcomings:

• procedural and cumbersome standard• programming of business transactions expensive and

error-prone• large maintenance efforts• an isolated standard

– future solution:• using the Internet’s infrastructure for business exchange

Page 6: OIL: An Ontology Infrastructure for the Semantic Web

OIL• HTML: initial, simplistic• XML: provides serialized

syntax for trees• RDF: defines a syntactical

convention and a simple data model – triples: object/property/value

• RDF Schema: introduces basic ontological primitives into the Web – classes, subclasses, subproperties, restrictions..

• OIL: based on RDFS, enriched into a full-fledged Web-based ontology language

Page 7: OIL: An Ontology Infrastructure for the Semantic Web

Criteria that OIL matches• We need an advanced ontology language to express

and represent ontologies. Must be:– highly intuitive to the human:

• OIL frame-based– central modeling primitives are classes (frames) with attributes

– well-defined formal semantics (completeness, correctness and efficiency)

• OIL description logics– knowledge is described in terms of concepts and role restrictions

– proper link to existing Web languages (XML, RDF)• OIL syntax in XML, based on RDF

– a standardized syntax for writing ontologies and a standard set of modeling primitives

Page 8: OIL: An Ontology Infrastructure for the Semantic Web

OIL’s layered architecture• Each layer adds

functionality and complexity to the previous one

• Core OIL: coincides with RDFS except reification features

• Standard OIL: specifying the semantics and making complete inferences viable

• Instance OIL: full-fledged database capability

• Heavy OIL: will include additional representational and reasoning capabilities

Page 9: OIL: An Ontology Infrastructure for the Semantic Web

An ontology

Page 10: OIL: An Ontology Infrastructure for the Semantic Web

OIL tools• Ontology editors

– build new ontologies• OntoEdit (U. Karlsruhe), OILed (U. Manchester), Protégé

(Stanford)

• Ontology-based annotation tools– we can derive an XML DTD and an XML Schema definition

from an ontology in OIL– we can derive an RDF and RDFS definition for instances

from OIL

• Reasoning with ontologies– reason about an ontology’s instances and schema definition

• FaCT

Page 11: OIL: An Ontology Infrastructure for the Semantic Web

Applications of OIL• Swiss Life: Organizational memory

– an intranet-based front end to an organizational memory

• British Telecom: Call centers– call center agents use a variety of electronic sources for

information when interacting with customers OIL provides front end tool

• EnerSearch: Virtual enterprise– is a virtual organization researching new IT-based business

strategies and customer services in deregulated energy markets OIL toolkit enhances knowledge transfer.

Page 12: OIL: An Ontology Infrastructure for the Semantic Web

Conclusions on OIL

• is properly grounded in Web languages (XML Schemas & RDFS)

• inner layers enable efficient reasoning support based on FaCT

• has a well-defined formal semantics