Semantic Web

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Semantic Web

• Meeyoung Park,
• 990023383, mp4y4_at_umkc.edu

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Paper

• Semantic Web Services
• By Sheila A. McIlraith, Tran Cao Son, and Honglei
  Zeng, IEEE Intelligent Systems,
  Computer.org/Intelligent, March/April 2001, Pages
  46-53.

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Contents

• Introduction
• Web
• Semantic Web
• Languages
• Semantic Web Services
• Research Challenges and Perspective
• Future Directions
• References

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Web Information Management
Fig.1 Tim Berners-Lee, CERN, March 1989, May
1990, ( http//www.w3.org/History/1989/proposal.h
tml )
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Web Current Web
Fig.2 Current Web
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Semantic Web

• The Semantic Web is
• an extension of the current web in which
  information is given well-defined meaning, better
  enabling computers and people to work in
  cooperation."
• ( Tim Berners-Lee, James Hendler, Ora Lassila,
  The Semantic Web, Scientific American, May 2001)
• a collaborative effort led by W3C with
  participation from a large number of researchers
  and industrial partners.
• based on the Resource Description Framework
  (RDF), which integrates a variety of applications
  using XML for syntax and URIs for naming.

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Semantic Web
Fig.3 Semantic Web
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The Semantic Web

• Why Semantic Web ?
• provides a common framework that allows data to
  be shared and reused across application,
  enterprise, and community boundaries.
• expresses web data in a machine-readable format.
• reduces language dependency and increase
  accessibility.

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Semantic Web Architectural Relationship
Fig.4 Semantic Web layer cake tresented by
Tim Berners-Lee at the XML 2000 Conference
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Languages for Semantic Web

• XML ( eXtensible Markup Language)
• a simple, very flexible text format derived from
  SGML.
• the first language to separate the markup of Web
  content from Web presentation.
• lacks semantics.
• ltsalarygt Vs. ltWagegt

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Resource Description Framework

• RDF is
• A standard for metadata
• a language for representing information about
  resources in the World Wide Web
• Why use RDF?
• Goal
• to add a formal semantics to the Web, defined on
  top of XML
• to provide a data model and syntax convention for
  representing the semantics of data in a
  standardized interoperable manner
• provides a means of describing the relationships
  among resources in terms of named properties and
  values.

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RDF data model
Fig.5 An RDF Graph Describing Eric Miller
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RDF Example

• lt?xml version"1.0"?gt
• ltrdfRDF xmlnsrdf"http//www.w3.org/1999/02/22-r
  df-syntax-ns" xmlnscontact"http//www.w3.org
  /2000/10/swap/pim/contact"gt
• ltcontactPerson
• rdfabout"http//www.w3.org/People/EM
  /contactme"gt
• ltcontactfullNamegtEric
  Millerlt/contactfullNamegt
• ltcontactmailbox rdfresource"mailtoe
  m_at_w3.org"/gt
• ltcontactpersonalTitlegtDr.lt/contactper
  sonalTitlegt lt/contactPersongt
• lt/rdfRDFgt

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DARPA Agent Markup Language

• What is DAML ?
• initiative to fund research in languages, tools,
  infrastructure, and applications
• to make Web content more accessible and
  understandable

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Why use DAML?

• RDF lacks
• Expressive power
• DAML provides
• a basic infrastructure that allows a machine to
  make the same sorts of simple inferences that
  human beings do.
• can allow you to conclude another DAML statement.

(motherOf subProperty parentOf) (Mary
motherOf Bill)
(Mary parentOf Bill)
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Ontology Inference Layer

• What is Ontology?
• A set of knowledge terms, including the
  vocabulary, the semantic interconnections, and
  some simple rules of inference and logic for some
  particular topic
• OIL (Ontology Inference Layer)
• a proposal for a web-based representation and
  inference layer for ontologies.
• designed to be an expressive description logic
  integrated with modern Web technology.

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DAMLOIL

• DAMLOIL is
• a semantic markup language for Web resources.
• a vocabulary of properties and classes added to
  RDF and RDF Schema.
• Why use DAMLOIL?
• overcomes expressiveness inadequacies plaguing
  RDF and RDFS.
• has a well-defined model-theoretic semantics.
• is unambiguously computer-interpretable, thus
  making it amenable to agent interoperability and
  automated-reasoning techniques.
• can manage large Web sites and document and image
  collections, integrating disparate databases.

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DAMLOIL Example

• lt!-- Revision 1.7 of Date 2001/06/06
  013821 . --gt
• ltrdfRDF
• xmlnsrdf "http//www.w3.org/1999/02/22-rdf-synt
  ax-ns" xmlnsrdfs"http//www.w3.org/2000/01/rdf-
  schema" xmlnsdaml"http//www.daml.org/2001/03/d
  amloil"
• xmlns "http//www.daml.org/2001/03/damloil" gt
  
• ltdamlClass rdfID"Animal"gt ltrdfslabelgtAnimallt/r
  dfslabelgt
• ltrdfscommentgt
• This class of animals is illustrative of a
  number of
• ontological idioms.
• lt/rdfscommentgt
• lt/damlClassgt
• ltdamlClass rdfID"Male"gt
• ltrdfssubClassOf rdfresource"Animal"/gt
• lt/damlClassgt
• ltdamlClass rdfID"Female"gt
• ltrdfssubClassOf rdfresource"Animal"/gt
  ltdamldisjointWith rdfresource"Male"/gt
• lt/damlClassgt

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Agents and the Semantic Web
Fig.6 Agents and the Semantic
Web http//www.semacticweb.org/
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Semantic Web services
Fig.7 A framework for Semantic Web services
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Semantic Web services enables..

• Automatic Web service discovery
• Involves automatically locating Web services.
• Find a service that sells airline tickets
  between San Francisco and Toronto and that
  accepts payment by Diners Club credit card.
• With Semantic markup of services, semantic
  search engine can automatically locate
  appropriate services.

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Semantic Web services enables..

• Automatic Web service execution
• Involves a computer program or agent
  automatically executing an identified Web
  services.
• Buy me an airline ticket from www.acmetravel.com
  on UAL flight 1234 from San Francisco to Toronto
  on March.3
• The markup tells the agent what input is
  necessary, what information will be returned, and
  how to execute the service automatically.

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Semantic Web services enables..

• Automatic Web Service composition and
  interoperation
• Involves the automatic selection, composition,
  and interoperation of appropriate Web services.
• Make the travel arrangements for my IJCAI2001
  conference trip.
• The information necessary to select, compose,
  and respond to services is encoded at the service
  web sites.

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DAML-enabled agent technology

• ConGolog
• A high-level logic programming language developed
  as the University of Toronto.
• For robot programming and to support high-level
  robot task programming.
• Built on top of situation calculus.

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Implementation

• Agent technology
• Online ConGolog interpreter in Quintus Prolog 3.2
• Open Agent Architecture agent brokering System.
• Web services
• Communicate through DAML.
• Markup DAMLOIL.
• Information extraction program World Wide
  Wrapper Factory(http/db.cis.upenn.edu/W4F)

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Example

• You want to travel from Kansas City to Chicago on
  conference with the university funded.
• Constraints
• you wish to drive rather than fly.
• You must use an American carrier for business
  travel.

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Research Challenges and Perspective

• The Semantic Web will enable
• Computers will be able to understand data in
  ways they cannot today.
• A more open market for information processing and
  computer services.
• Applications
• Applications for organization
• Ontology-based market place development for B2B
  e-commerce.
• Bioinformatics.
• Application for the masses
• Intelligent personal assistant that gathers
  information.

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Semantic Web Services Example

• The Semantic Web Site
• http//www.brandsoft.com
• http//musicbrainz.com
• Semaview's Sherpa
• Dublin Core Metadata Initiative
• Searching - TAP

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Future Directions

• Facilitate Semantic Web infrastructure
• stimulate the network effect of data.
• Development of ontology registries for Open
  vocabularies to help bootstrap application
  deployment in interoperable manners.
• Investigate additional enabling standards that
  help build the Semantic Web.

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References

• The semantic web and its languages, Dieter
  Fensel, IEEE Intelligent Systems,
  November/December 2000, Pages 67-73.
• Agents and the Semantic Web, Hendler, J.,
  Intelligent Systems, IEEE, Volume 16 , Issue 2
  , March-April 2001, Pages 30 37
• DAMLOIL An Ontology Language for the Semantic
  Web, Mcguinness, D.L, Fikes, R., Hendler, J.,
  Stein, L.A., Intelligent Systems, IEEE , Volume
  17 , Issue 5 , Sept.-Oct. 2002 , Pages 72 80
• Research Challenges and Perspectives of the
  Semantic Web, Euzenat, J., Intelligent Systems,
  IEEE, Volume 17 , Issue 5 , Sept.-Oct. 2002
  Pages86 88

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Useful Sites

• SemanticWeb.Org
• http//www.semanticweb.org/
• World Wide Web Consortium (W3C)
• http//www.w3.org/
• Resource Description Framework (RDF)
• http//www.w3.org/RDF/
• Web-Ontology (WebOnt) Working Group
• http//www.w3.org/2001/sw/WebOnt/
• Extensible Markup Language (XML)
• http//www.w3.org/XML/
• DARPA Agent Markup Language (DAML)
• http//www.daml.org
• Ontology.Org
• http//www.ontology.org/

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Thank you!
Any Questions ?