Semantic Web by yantingting

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									Bringing RDF to Digital Contents
      Towards the Semantic Web

                   Ching-Long Yeh
    Department of Computer Science and Engineering
                   Tatung University
            chingyeh@cse.ttu.edu.tw (msn)
          http://www.cse.ttu.edu.tw/chingyeh
                    Web Technology Overview
•   WWW (human-to-machine interactions)
     – Infrastructure
          • HTML, HTTP, URI, browsers
     – Services
          • Search engine and directory navigation
•   WWW + XML (human-to-machine and machine-to-machine interactions)
     – Web Services (UDDI, WSDL, SOAP)
          • SOA (Registry, provider, requester)
          • Automatic service processing
     – ebXML
          • SOA for business automation
                –   discovery, implementation, run-time phases
          • Business process + message service
     – Semantic Web
          •   Meaning processing automation
          •   WWW + metadata layer (OWL+RDF)
          •   Services automation (WWW+OWL-S/RDF)
          •   Semantic Grid



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                         Semantic Web
•   The Semantic Web is a vision:


          the idea of having data on the web defined and linked in a
          way that it can be used by machines not just for display
          purposes, but for automation, integration and reuse of data
          across various applications




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                      Semantic Web

• The Semantic Web = a Web with a meaning.


     "If HTML and the Web made all the online documents
     look like one huge book, RDF, schema, and inference
     languages will make all the data in the world look like
     one huge database“

     Tim Berners-Lee, Weaving the Web, 1999




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    Introduction from W3C SW Activity

• The Semantic Web is a web of data.
• The Semantic Web is about two things.
   – Common formats for interchange of data,
       • On the original Web we only had interchange of documents.
   – Language for recording how the data relates to real world objects
       • That allows a person, or a machine, to start off in one database, and then
         move through an unending set of databases which are connected not by
         wires but by being about the same thing.




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                The Semantic Web Architecture

                                                                     Trust
                                                               Proof
Tim Berners-Lee:
“Axioms, Architecture and Aspirations”                      Logic (FOL)
W3C all-working group plenary Meeting
28 February 2001                                          Rules (SWRL)
(http://www.w3.org/2001/Talks/0228-                                          Sig./
tbl/slide5-0.html)                                      Ontology (OWL)
                                                                             Ency.
I. Horrocks, et al. Semantic web architecture:           RDF Schema
Stack or two towers? In F. Fages and S.
Soliman, (eds.), Principles and Practice of              RDF M&S
Semantic Web Reasoning (PPSWR 2005),
number 3703 in LNCS, pages 37-41. SV,                   XML Schema
2005.
http://www.cs.man.ac.uk/~horrocks/Publicatio
ns/download/2005/HPPH05.pdf
                                                  XML          Namespaces
                                                 URI               Unicode
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RDF and Schema Languages
                      RDF M&S
• RDF (Resource Description Framework)
• RDF consists of two parts
   – RDF Model (a set of triples)
   – RDF Syntax (different XML serialization syntaxes)
• RDF Schema for definition of Vocabularies (simple
  Ontologies) for RDF (and in RDF)




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                  RDF Data Model
• Resources
   – A resource is a thing you talk about (can reference)
   – Resources have URI’s
• Properties
   – slots, define relationships to other resources or atomic values
• Statements
   – “Resource has Property with Value”
   – (Values can be resources or atomic XML data)
• Similar to Frame Systems



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                   A Simple Example
• Statement
   – “Ora Lassila is the creator of the resource http://www.w3.org/Home/Lassila”
• Structure
   – Resource     (subject)      http://www.w3.org/Home/Lassila
   – Property     (predicate)      http://www.schema.org/#Creator
   – Value        (object)         "Ora Lassila”

• Directed graph

                                      s:Creator           Ora Lassila
http://www.w3.org/Home/Lassila




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                   Another Example

• To add properties to Creator, point through an intermediate
  Resource.


                  http://www.w3.org/Home/Lassila

                             s:Creator

                                   Person://fi/654645635


                                   Name              Email


                              Ora Lassila          lassila@w3.org




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                        Example: Bag
•   The students in
    course 6.001
     are Amy, Tim,
    John, Mary,         /courses/6.001
                                                    Rdf:Bag
    and Sue
                                         rdf:type
                                                                          /Students/Amy
                      students
                                                     rdf:_1
                                                              rdf:_2      /Students/Tim

                            bagid1                             rdf:_3
                                                                          /Students/John
                                                                rdf:_4

                                                                           /Students/Mary
                                                                 rdf:_5

                                                                           /Students/Sue
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                      Example: Alternative
•   The source code for X11 may be found at ftp.x.org, ftp.cs.purdue.edu, or
    ftp.eu.net



             http://x.org/package/X11
                                                    rdf:Alt

                                         rdf:type
                      source


                                                    rdf:_1
                                 altid                            ftp.x.org
                                                     rdf:_2

                                                               ftp.cs.purdue.edu
                                                      rdf:_3

                                                                  ftp.eu.net
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<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
             xmlns:contact="http://www.w3.org/2000/10/swap/pim/contact#">

 <contact:Person rdf:about="http://www.w3.org/People/EM/contact#me">
   <contact:fullName>Eric Miller</contact:fullName>
   <contact:mailbox rdf:resource="mailto:em@w3.org"/>
   <contact:personalTitle>Dr.</contact:personalTitle>
 </contact:Person>

</rdf:RDF>
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                          OWL
             W3C Web Ontology Language
• OWL provides three increasingly expressive sublanguages:
  OWL Lite, OWL DL, and OWL Full.




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                                     OWL
                 W3C Web Ontology Language

                     OWL Lite language constructs
RDF Schema Features:          (In)Equality:           Property Characteristics:
Class                         equivalentClass         inverseOf
rdf:Property                  equivalentProperty      TransitiveProperty
rdfs:subClassOf               sameAs                  SymmetricProperty
rdfs:subPropertyOf            differentFrom           FunctionalProperty
rdfs:domain                   allDifferent            InverseFunctionalProperty
rdfs:range
Individual

Property Type Restrictions:     Restricted Cardinality:         Header Information:
allValuesFrom                   minCardinality (only 0 or 1)    ontology
someValuesFrom                  maxCardinality (only 0 or 1)    imports
                                cardinality (only 0 or 1)

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Semantic Web System Architectures
Typical System Architecture




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Layered Architecture




                       19
                          Sesame
A generic Architecture for Storing and Querying RDF and RDF Schema




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Adding RDF Metadata to PW




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    RDF/OWL Representation of WordNet
•   WordNet [Fellbaum, 1998] is a heavily-used lexical resource in natural-
    language processing and information retrieval.
•   More recently, it has also been adopted in Semantic Web research
    community.
•   It is used mainly for annotation and retrieval in different domains such as
    cultural heritage [Hollink et al., 2003], product catalogs [Guarino et al.,
    1999] and photo metadata [Brickley, 2002].
•   It is also used to ground other vocabularies such as the FOAF schema
    [Brickley and Miller, 2005], as background knowledge in ontology
    alignment tools and other applications (see
    http://esw.w3.org/mt/esw/archives/cat_applications_and_demos.html for a
    list).
•   Currently there exist several conversions of WordNet to RDF(S) or OWL.

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 Class Hierarchy of the WordNet Schema
Synset
  AdjectiveSynset
       AdjectiveSatelliteSynset
  AdverbSynset
  NounSynset
  VerbSynset
WordSense
  AdjectiveWordSense
       AdjectiveSatelliteWordSense
  AdverbWordSense
  NounWordSense
  VerbWordSense
Word
  Collocation

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Combining the Metadata of Digital Content
             with WordNet




   The metadata database



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Combining the Metadata of Digital Content
             with WordNet




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Combining the Metadata of Digital Content
             with WordNet




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Combining the Metadata of Digital Content
             with WordNet




                                            27
Combining the Metadata of Digital Content
             with WordNet




                                            28
Combining the Metadata of Digital Content
             with WordNet




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             Use of RDF Metadata (1)

• Integrating existing programs into the Semantic Web
   – Newer versions of Picture Write
   – Newer versions of PMLS




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               Use of RDF Metadata (2)

• Effective management of digital contents
   –   Defining standard vocabularies (ontology)
   –   Classifications of digital content
   –   Conceptual search and semantic navigation
   –   Web services




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               Use of RDF Metadata (3)

• Making digital contents more beneficial
   – Pictures bundled with RDF metadata can be further processed by
     clients.
   – We sell digital content not only for presentation but also for meaning
     processing.
       • We sell not only physical files of pictures but also their metadata.
   – New business model (?)




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              Use of RDF Metadata (4)

• Automatic generation of pictures sequence to extend the scope
  of pictures from word level to phrase or even sentence level
   – Natural language processing technology is employed to enhance the
     current word-level matching method.
   – The RDF metadata can be seen as the knowledge base to support
     advanced processing using the natural language processing technique.




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Thank You

								
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