PowerPointPrsentation

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State of the Art in Ontology Engineering and
Web Ontology Language (OWL)
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• In Philosophy
• "Ontology as a branch of philosophy is the
  science of 'what is', of the kinds and
  structures of objects, properties, events,
  processes and relations in every area of
  reality.
• Barry Smith. Formal Ontology and Information
  Systems, New York ACM Press, 2001
• In Computer Science
• "An ontology is a formal, explicit specification
  of a shared conceptualization.
• T.R. Gruber. A Translation approach to
  portable ontologies. Knowledge Acquisition.
  5(2)199-220, 1993
• Rules, logics, proofs are parts of ontologies,
  but not yet at a consensus level for
  standardization, however work on this subject is
  in progress
• (A Proposal for an OWL Rules Language
  http//www-db.research.bell-labs.com/user/pfps/pub
  lications/owl-rules-proposal.pdf)
• The current focus of ontology engineering is how
  to merge and integrate already existing
  ontologies.

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• To Assist Communication between People
• who have different needs and viewpoints depending
  on their differing contexts so that we can
  minimize ambiguity
• To Achieve Inter-Operability among Computer
  Systems
• by translating between different modeling
  methods, paradigms, languages and software tools
• To Improve the Process of Engineering Software
  Systems by means of
• Re-usability
• Reliability (formal representation enables
  consistency checking)
• Specification (identifying requirements and
  defining a specification for an IT system)
• Adapted from A Framework for Understanding and
  Classifying Ontology Aplications. (1999) Robert
  Jasper, Mike Uschold

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CARNEGIE-MELLON UNIVERSITY RETSINA SEMANTIC WEB
CALENDAR AGENT
Uses the iCal scheduling ontology Schedules
meetings with other users using the Agent
Browses schedules available on the Semantic Web
Imports selected schedules and events into
Microsoft Outlook Sends email to attendees
listed within the marked up schedules Requests
and organise meetings with event attendees.
Intelligent Software Agents Laboratory The
Robotics Institute http//www-2.cs.cmu.edu/softag
ents/cal/Esec
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Natural Language Processing Ontology based
Information Retrieval Mechanism of CYCORP
Ontology
When does the REWERSE meeting start?
Natural Language Query
Formal Query
HTML
WWW
Formal Query
REWERSE meeting starts at 8.30 p.m. on Monday
CYCORP http//www.cyc.com/
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Natural Language Processing Ontology based
Information Extraction Mechanism of CYCORP
Ontology
date is-a kind-of fruit T date is-a-kind-of
temporalconcept F
Jane ate quite a few dates (Datteln)
? date is-a fruit ?date is-a temporalconcept
date is-a fruit T date is-a temporalconcept F
Handling Ambiguity with Ontologies
CYCORP http//www.cyc.com/
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Adapted
fromMcGuiness, Cogna October, 2003
Web Languages RDF/S XML
Web Languages RDF/S XML
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
OIL
Formal Foundations Description Logics
Frame Systems
FACT, CLASSIC, DLP,
FACT, CLASSIC, DLP,
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OWL has 3 Sublanguages
OWL FULL
Web Languages RDF/S XML
OWL DL
OWL LITE
OWL (DAMLOIL)
DAML-ONT

• OWL FULL corresponds to RDF Model i.e.
• e.g. http//www.example.org/index.html has a
  creator whose value is John Smith
• Knowledge Level http//www.example.org/index.ht
  ml has a creator whose value is John Smith
• Representation Level (Object)
  (arc) (Value)
• (Subject)
  (predicate) (Object)
• (Subject)
  (property) (Value)
•  hasCreator(http//www.example.org/index.html ,
  John Smith)
• OWL DL is more restricted and is based on
  Description Logics
• OWL LITE is the most restricted one with the
  least expressivity. e.g. cardinality values
  allowed only 0 or 1

OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Web Languages RDF/S XML

• Class Declarations
• -class identifier (built-in owlThing,
  owlNothing)
• -property restriction classe(owlallValue
  sFrom, owlsomeValuesFrom, owlhasValue)
• Class Axioms
• oneOf (enumerated classes)
• DisjointWith
• sameClass
• rdfssubClassOf
• equivalentClass
• Combinations of Class Exp.
• unionOf
• IntersectionOf
• complementOf
• Arbitrary Cardinality
• minCardinality
• maxCardinality
• cardinality

OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Property Declarations Object properties
Datatype properties Property
Axioms rdfssubPropertyOf rdfsdomain rdfsrange
owlequivalentProperty owlinverseOf owlFunctiona
lProperty (propertys max. cardinality is 1 and
min. cardinality is 0 e.g. hasPrimaryEmployer) ow
lInverseFunctionalProperty (the inverse of the
property is functional e.g. isThePrimaryEmployerFo
r) owlTransitiveProperty owlSymmetricProperty  
Web Languages RDF/S XML
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Web Languages RDF/S XML
Individuals  owlsameAs
owldifferentFrom
owlAllDifferent Annotations
owlversionInfo , rdfslabel , rdfscomment ,
rdfsseeAlso, rdfsisDefinedBy OWL DL is
computationally complete (all
entailments are guaranteed to be computed)
decidable (all computations will finish in
finite time) does type separation so
that a class can not also be an individual or
property, a property can not also be an
individual or class (permitted in OWL Full)
so we avoid
x rdftype owlClass (VW is an
instace of class Car) y
rdftype owlClass (Porsche is an instance of
class Car) x rdftype y (VW is an
instance of Porsche)  
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Web Languages RDF/S XML
Web Languages RDF/S XML
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Web Languages RDF/S XML
Web Languages RDF/S XML
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Web Languages RDF/S XML
Web Languages RDF/S XML
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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Web Languages RDF/S XML
Web Languages RDF/S XML
OWL (DAMLOIL)
DAML-ONT
OIL
DAMLOIL (OWL)
DAML-ONT
Formal Foundations Description Logics
FACT, CLASSIC, DLP,
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