Bringing RDF to Digital Contents Towards the Semantic Web Ching-Long Yeh Department of Computer Science and Engineering Tatung University (msn)

Bringing RDF to Digital Contents2 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 Contents3 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 Contents4 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 Contents5 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 Contents6 The Semantic Web Architecture ( tbl/slide5-0.html) Tim Berners-Lee: “Axioms, Architecture and Aspirations” W3C all-working group plenary Meeting 28 February 2001 URIUnicode XMLNamespaces XML Schema Sig./ Ency. RDF M&S RDF Schema Ontology (OWL) Rules (SWRL) Logic (FOL) Proof Trust 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 SV, ns/download/2005/HPPH05.pdf

RDF and Schema Languages

Bringing RDF to Digital Contents8 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 Contents9 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 Contents10 A Simple Example Statement –“Ora Lassila is the creator of the resource ” Structure –Resource(subject) –Property(predicate) –Value(object) "Ora Lassila ” Directed graph s:Creator Ora Lassila

Bringing RDF to Digital Contents11 Name s:Creator Another Example To add properties to Creator, point through an intermediate Resource. Person://fi/ Ora Lassila

Bringing RDF to Digital Contents12 Example: Bag The students in course are Amy, Tim, John, Mary, and Sue Rdf:Bag /Students/Amy /Students/Tim /Students/John /Students/Mary /Students/Sue bagid1 /courses/6.001 students rdf:type rdf:_1 rdf:_2 rdf:_3 rdf:_4 rdf:_5

Bringing RDF to Digital Contents13 rdf:_1 rdf:_2 rdf:_3 rdf:type source ftp.eu.net ftp.cs.purdue.edu ftp.x.org Example: Alternative The source code for X11 may be found at ftp.x.org, ftp.cs.purdue.edu, or ftp.eu.net altid rdf:Alt

Bringing RDF to Digital Contents14 <rdf:RDF xmlns:rdf=" xmlns:contact=" Eric Miller Dr.

Bringing RDF to Digital Contents15 OWL W3C Web Ontology Language OWL provides three increasingly expressive sublanguages: OWL Lite, OWL DL, and OWL Full.

Bringing RDF to Digital Contents16 OWL W3C 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

Semantic Web System Architectures

Bringing RDF to Digital Contents18 Typical System Architecture

Bringing RDF to Digital Contents19 Layered Architecture

Bringing RDF to Digital Contents20 Sesame A generic Architecture for Storing and Querying RDF and RDF Schema

Bringing RDF to Digital Contents21 Adding RDF Metadata to PW

Bringing RDF to Digital Contents22 RDF/OWL Representation of WordNet WordNet [Fellbaum, 1998] is a heavily-used lexical resource in natural- language processing and information retrieval.Fellbaum, 1998 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].Hollink et al., 2003Guarino et al., 1999Brickley, 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 for a list).Brickley and Miller, Currently there exist several conversions of WordNet to RDF(S) or OWL.

Bringing RDF to Digital Contents23 Class Hierarchy of the WordNet Schema Synset AdjectiveSynset AdjectiveSatelliteSynset AdverbSynset NounSynset VerbSynset WordSense AdjectiveWordSense AdjectiveSatelliteWordSense AdverbWordSense NounWordSense VerbWordSense Word Collocation

Bringing RDF to Digital Contents24 Combining the Metadata of Digital Content with WordNet The metadata database

Bringing RDF to Digital Contents25 Combining the Metadata of Digital Content with WordNet

Bringing RDF to Digital Contents26 Combining the Metadata of Digital Content with WordNet

Bringing RDF to Digital Contents27 Combining the Metadata of Digital Content with WordNet

Bringing RDF to Digital Contents28 Combining the Metadata of Digital Content with WordNet

Bringing RDF to Digital Contents29 Combining the Metadata of Digital Content with WordNet

Bringing RDF to Digital Contents30 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 Contents31 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 Contents32 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 Contents33 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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