The Semantic Web

1
The Semantic Web

• The Next Evolution of the WWW

Fall 2005
2
Overview

• What is the Semantic Web?
• Background
• Components of the Semantic Web
• Why the Semantic Web is needed
• Uses of the Semantic Web
• Implementing the Semantic Web
• Examples
• Conclusion

3
What is the Semantic Web?

• The Semantic Web is "an extended web of
  machine-readable information and automated
  services that amplify the Web far beyond current
  capabilities" (Daconta et al., 2003)

• A framework that
• Adds meaning to data
• Provides a mechanism for organizing,
  interpreting, and making use of that meaning

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What is the Semantic Web? (cont)

• An enhancement to the current Web, not a
  replacement

• The Semantic Web will bring structure to the
  meaningful content of Web pages, creating an
  environment where software agents roaming from
  page to page can readily carry out sophisticated
  tasks for users (Berners-Lee et al., 2001)

5
Background

• 1968 Internet used as a communications network
  by DOD
• 1989 Tim Berners-Lee (and others) at CERN
  develop HTML from SGML
• Early 1990s Web browsers created to interpret
  HTML
• 1996 XML developed
• 1990s Tim Berners-Lee W3C continue to pursue
  development the Semantic Web

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Components of the Semantic Web

• Four major components
• XML
• Resource Description Framework (RDF)
• Ontologies
• Agents

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Supplemental Components of the Semantic Web

• Supplemental components
• Uniform Resource Identifiers (URIs)
• Web services
• Inference rules
• Service discovery
• Semantic aware applications
• Security and trust
• XML and RDF schemas

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XML

• HTML (XHTML) is a series of predefined tags that
  add presentation to data
• ltbgtThis text is boldlt/bgt
• XML is a series of user-defined tags that add
  information and structure to data
• ltauthorgtJohn Smithlt/authorgt

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XML (cont)

• "XML has become the universal syntax for
  exchanging data between organizations" (Daconta
  et al., 2003)
• Issue
• Some mechanism must exist for coordinating the
  meaning of the user-defined tags and for
  understanding the context of that information
• Company A ltnamegtSmithlt/namegt
• Company B ltemployeegtJoneslt/employeegt
• Company C ltnamegtWilliamslt/namegt

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Resource Description Framework (RDF)

• An XML-based language used to describe resources
• Resources can include entities, concepts,
  properties and relations
• Captures the meta data about the externals of a
  document
• Can use a serialized model, RDF triplets, special
  notation, or graphs to describe data

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Resource Description Framework (RDF) (cont)

• Example serialized model
• RDF triplet (subject, predicate, object/literal)

Software
sells
Company
Microsoft
Is named
The company sells software The company is named
Microsoft John Smith is the president of Company X
Next
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• lt?xml version'l.0' encoding'ISO-8859-1'?gt
• ltrdfRDF xmlnsrdf"http//www.w3.org/1999/02/22-r
  df-syntax-na"
• xmlnsrdfs"http//www.w3.org/TR/1999/PR-rdf-sche
  ma-19990303" xmlnss0"http//wr7w.w3.org/2000/P
  hotoRDF/dc-1-0"
• xmlnssl"http//sophia.inria.fr/-enerbonn/rdfpic
  lang" xmlnss2"http//www.w3.org/2000/PhotoRDF/
  technical-l-0"gt
• ltrdfDescription rdfabouthttp//www.c2i2.com/b
  udstv/images/shopl.jpg"gt
• lts0relationgtpart-of Store Frontlt/s0relationgt
• lts0typegtimagelt/s0typegt
• lts0formatgtimage/jpeglt/s0formatgt
• ltslxmllanggtenlt/slxrnllanggt
• lts0descriptiongtBuddy Belden's work bench for
  TV/VCR repairlt/s0descriptiongt
• lts2cameragtKodak EasySharelt/s2cameragt
• lts0titlegtTV Shop repair benchlt/s0titlegt
• lt/rdfDescriptiongt
• lt/rdfRDFgt
• Source The Semantic Web, Dacaonta, Obrst,
  Smith (2003)

Back
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Ontologies
the common words and concepts (the meaning) used
to describe and represent an area of knowledge"
(Daconta et al., 2003)

• Provide the repositories for meaning
  interpretations
• Provide a mechanism for defining the relationship
  among different words and for the Semantic Web,
  relationships among different resources

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Ontologies (cont)

• Consist of
• Taxonomies
• An organized set of terms. (McComb, 2004)
• A classification and a tree (Daconta et al.,
  2003)
• Hierarchal, tree-like structures similar to
  organizational charts
• Example
• Sets of inference rules
• Should be used to organize semantics, but not
  knowledge

Next
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Taxonomy Example
Back
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Agents

• Also known as software agents
• Provide automation services
• Should not be designed to replace humans or to
  make decisions
• Examples Web spiders and crawlers

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Supplemental Components of the Semantic Web

• Uniform Resource Identifiers (URIs)
• Provide a mechanism for identifying available
  resources
• The super-set of URNs, URLs and URCs
• Web services
• Allow computer applications to communicate
  directly with each other over the Internet
• Inference rules
• Define the relationships and rules between data

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Supplemental Components of the Semantic Web (cont)

• Service discovery
• Allows applications to find ontologies and agents
• Semantic aware applications
• Applications that can make use of semantic
  information
• Security and trust
• XML schema
• Define the structure of XML documents
• Standardizes the communication between systems
• RDF schema or OWL
• Can be used to define the language used in
  ontologies and RDFs

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Why the Semantic Web is Needed

• The current Web remains largely unstructured
  (e.g., company)
• Large amounts of information remain unavailable

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Uses of the Semantic Web

• Improve e-business processes
• Improve business-to-business (B2B) communication
• assist human users in their day-to-day online
  activities (Antoniou van Harmelen, 2004)
• build knowledge and understanding from raw data
  (Daconta et al., 2003)
• Improve knowledge management
• Improve information retrieval
• Automate tasking
• Integrate data
• Maximize customer value and profits

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Implementing the Semantic Web

• Convert data to XML format according to defined
  XML schemas
• Expose applications as Web services
• Build ontologies that specify semantic meanings
  and the relationships between data
• Create agents that make use of the semantic data,
  automate search processes, and automate other
  business processes

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Issues Concerned with Implementing the Semantic
Web

• Cost
• Security
• Nonstandard technology issues
• Semantic precision

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Examples

• http//www.foaf-project.org/
• http//www.cs.umd.edu/users/hendler/
• http//www.cs.umd.edu/projects/plus/SHOE/cs.html
• http//www.daml.ri.cmu.edu/Cal/
• http//www.semanticwebsearch.com/reference.rsp

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Conclusion

• What is the Semantic Web?
• Background
• Components of the Semantic Web
• Why the Semantic Web is needed
• Uses of the Semantic Web
• Implementing the Semantic Web
• Issues concerned with implementing the Semantic
  Web
• Examples
• Questions?

25
References

• Antoniou, G., van Harmelen, F. (2004). A
  semantic Web primer. Cambridge, MA The MIT
  press.
• Athauda, R. I. (2000). Integration and querying
  of heterogeneous, autonomous, distributed
  database systems (Vol. 61/06, pp. 3126) Florida
  International University.
• Berners-Lee, T., Hendler, J., Lassila, O.
  (2001). The Semantic Web. Scientific American,
  284(5), 34-43.
• Carey, P., Kemper, M. (2003). New perspectives
  on creating Web pages with HTML and Dynamic HTML
  (2nd ed.). Boston Course Technology.
• Daconta, M. C., Obrst, L. J., Smith, K. T.
  (2003). The Semantic Web A guide to the future
  of XML, Web services, and knowledge management.
  Indianapolis, IN Wiley Publishing, Inc.
• Ewalt, D. M. (2002, October 14). Semantic Web.
  InformationWeek, 35-44.
• Galitz, W. O. (2002). The essential guide to user
  interface design. New York John Wiley Sons,
  Inc.

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References

• Gould, M. (1996). Rules in the virtual society.
  International Review of Law, Computers
  Technology, 10(2), 199-218.
• Kalakota, R., Robinson, M. (2001). e-Business
  2.0 Roadmap for success. Upper Saddle River, NJ
  Addison-Wesley.
• Lexico Publishing Group, L. (2004). Inference.
  Retrieved December 7, 2004, from
  http//dictionary.reference.com/search?qinference
  
• McComb, D. (2004). Semantics in business systems
  The savvy manager's guide. San Francisco, CA
  Morgan Kaufmann Publishers.
• Tiwana, A. (2002). The knowledge management
  toolkit. Upper Saddle River, NJ Prentice Hall
  PTR.
• Warren, P. (2003). The next steps for the WWW
  Putting meaning into the Web. Computing Control
  Engineering, 14(2), 27-31.
• Young, M. J. (2002). XML step by step (2nd ed.).
  Redmond, WA Microsoft Press.