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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
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Bringing RDF to Digital ContentsTowards 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 Bringing RDF to Digital Contents
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 Bringing RDF to Digital Contents
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 Bringing RDF to Digital Contents
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. Bringing RDF to Digital Contents
The Semantic Web Architecture Trust Proof Sig./ Ency. Tim Berners-Lee: “Axioms, Architecture and Aspirations” W3C all-working group plenary Meeting 28 February 2001 Logic (FOL) Rules (SWRL) (http://www.w3.org/2001/Talks/0228-tbl/slide5-0.html) Ontology (OWL) RDF Schema I. Horrocks, et al. Semantic web architecture: Stack or two towers? In F. Fages and S. Soliman, (eds.), Principles and Practice of Semantic Web Reasoning (PPSWR 2005), number 3703 in LNCS, pages 37-41. SV, 2005. http://www.cs.man.ac.uk/~horrocks/Publications/download/2005/HPPH05.pdf RDF M&S XML Schema XML Namespaces URI Unicode Bringing RDF to Digital Contents
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) Bringing RDF to Digital Contents
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 Bringing RDF to Digital Contents
Ora Lassila 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 http://www.w3.org/Home/Lassila Bringing RDF to Digital Contents
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 Bringing RDF to Digital Contents
/courses/6.001 Example: Bag • The students incourse 6.001 are Amy, Tim,John, Mary,and Sue Rdf:Bag rdf:type /Students/Amy students rdf:_1 rdf:_2 /Students/Tim bagid1 rdf:_3 /Students/John rdf:_4 /Students/Mary rdf:_5 /Students/Sue Bringing RDF to Digital Contents
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 altid rdf:_1 ftp.x.org rdf:_2 ftp.cs.purdue.edu rdf:_3 ftp.eu.net Bringing RDF to Digital Contents
<?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> Bringing RDF to Digital Contents
OWLW3C Web Ontology Language • OWL provides three increasingly expressive sublanguages: OWL Lite, OWL DL, and OWL Full. Bringing RDF to Digital Contents
OWLW3C Web Ontology Language OWL Lite language constructs RDF Schema Features: Class rdf:Property rdfs:subClassOf rdfs:subPropertyOf rdfs:domain rdfs:range Individual (In)Equality: equivalentClass equivalentProperty sameAs differentFrom allDifferent Property Characteristics: inverseOf TransitiveProperty SymmetricProperty FunctionalProperty InverseFunctionalProperty Property Type Restrictions: allValuesFrom someValuesFrom Restricted Cardinality: minCardinality (only 0 or 1) maxCardinality (only 0 or 1) cardinality (only 0 or 1) Header Information: ontology imports Bringing RDF to Digital Contents
Typical System Architecture Bringing RDF to Digital Contents
Layered Architecture Bringing RDF to Digital Contents
SesameA generic Architecture for Storing and Querying RDF and RDF Schema Bringing RDF to Digital Contents
Adding RDF Metadata to PW Bringing RDF to Digital Contents
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. Bringing RDF to Digital Contents
Class Hierarchy of the WordNet Schema Synset AdjectiveSynset AdjectiveSatelliteSynset AdverbSynset NounSynset VerbSynset WordSense AdjectiveWordSense AdjectiveSatelliteWordSense AdverbWordSense NounWordSense VerbWordSense Word Collocation Bringing RDF to Digital Contents
Combining the Metadata of Digital Content with WordNet The metadata database Bringing RDF to Digital Contents
Combining the Metadata of Digital Content with WordNet Bringing RDF to Digital Contents
Combining the Metadata of Digital Content with WordNet Bringing RDF to Digital Contents
Combining the Metadata of Digital Content with WordNet Bringing RDF to Digital Contents
Combining the Metadata of Digital Content with WordNet Bringing RDF to Digital Contents
Combining the Metadata of Digital Content with WordNet Bringing RDF to Digital Contents
Use of RDF Metadata (1) • Integrating existing programs into the Semantic Web • Newer versions of Picture Write • Newer versions of PMLS Bringing RDF to Digital Contents
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 Bringing RDF to Digital Contents
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 (?) Bringing RDF to Digital Contents
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. Bringing RDF to Digital Contents