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Linked Data Technology & Status

Linked Data Technology & Status. Dr. Myungjin Lee. The Semantic Web. more vocabulary for describing properties and classes. a vocabulary for describing properties and classes of RDF-based resources. to exchange rules between many "rules languages ".

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Linked Data Technology & Status

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  1. Linked DataTechnology & Status Dr. Myungjin Lee

  2. The Semantic Web more vocabulary for describing properties and classes a vocabulary for describing properties and classes of RDF-based resources to exchange rules between many "rules languages" a protocol and query language for semantic web data sources an elemental syntax for content structure within documents a simple language for expressing data models, which refer to objects ("resources") and their relationships a string of characters used to identify a name or a resource Linked Data & Semantic Web Technology http://www.w3.org/2007/Talks/0130-sb-W3CTechSemWeb/#(24)

  3. What is Linked Data? Linked data describes a method of publishing structured data so that it can be interlinked and become more useful. The Semantic Web isn't just about putting data on the web. It is about making links, so that a person or machine can explore the web of data. With linked data, when you have some of it, you can find other, related, data. - A roadmap to the Semantic Web by Tim Berners-Lee http://www.w3.org/DesignIssues/LinkedData.html

  4. Four Principles of Linked Data • Use URIs to identify things. • Use HTTP URIs so that these things can be referred to and looked up ("dereferenced") by people and user agents. • Provide useful information about the thing when its URI is dereferenced, using standard formats such as RDF/XML. • Include links to other, related URIs in the exposed data to improve discovery of other related information on the Web. http://www.w3.org/DesignIssues/LinkedData.html

  5. 5 Star Linked Data http://www.w3.org/DesignIssues/LinkedData.html

  6. The Basic Requirements for Linked Data a vocabulary for describing properties and classes of RDF-based resources a protocol and query language for semantic web data sources an elemental syntax for content structure within documents a simple language for expressing data models, which refer to objects ("resources") and their relationships a string of characters used to identify a name or a resource Linked Data & Semantic Web Technology

  7. http://www.google.co.kr/search?q=namdeamun

  8. URI, Thing, and Representation looks up URI Person http://data.kdata.kr/resource/Namdaemun Machine refers URI http://data.kdata.kr/resource/Sungnyemun identifies and names links URI Thing http://dbpedia.org/resource/Namdaemun represents Representation <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>Namdaemun | kdata.kr</title> <link rel="alternate" type="application/rdf+xml" href="http://data.kdata.kr/data/Namdaemun" title="RDF" /> </head> <body onLoad="init();"> <div id="header"> <div> <h1 id="title">Namdaemun</h1> <div id="homelink"> &nbsp;at <a href="http://kdata.kr">kdata.kr</a> http://www.slideshare.net/lysander07/open-hpi-semweb02part1

  9. http://www.w3.org/TR/cooluris/

  10. URIs for Real-World Objects • Be on the Web • Given only a URI, machines and people should be able to retrieve a description about the resource identified by the URI from the Web. • Be unambiguous • There should be no confusion between identifiers for Web documents and identifiers for other resources. http://www.w3.org/TR/cooluris/

  11. URIs for Real-World Objects <URI-of-alice> a foaf:Person; foaf:name"Alice"; foaf:mbox<mailto:alice@example.com>; foaf:homepage<http://www.example.com/people/alice> . Resource identifier (URI) ID for semantic web applications for web browsers RDF HTML RDF document URI HTML document URI http://www.w3.org/TR/cooluris/

  12. Distinguishing between Representations and Descriptions http://data.kdata.kr/resource/Namdaemun Thing 303 redirect http://data.kdata.kr/page/Namdaemun Generic Document application/rdf+xml text/html content negotiation RDF HTML http://data.kdata.kr/page/Namdaemun.rdf http://data.kdata.kr/page/Namdaemun.html

  13. Cool URIs • Simplicity • short and mnemonic • Stability • remain as long as possible • Manageability • issue your URIs in a way that you can manage http://www.w3.org/TR/cooluris/

  14. Designing URI Sets for the UK Public Sector • URIs: • name the set and describe its characteristics • identify for the real-world ‘Things’ in a single concept • provide a means of looking up data on the web • provide mechanisms to: • lookup an Identifier URI and be redirected to its Document URI • discover and get each of the Representation URIs https://www.gov.uk/government/publications/designing-uri-sets-for-the-uk-public-sector http://data.gov.uk/resources/uris

  15. URI Design Principles:Creating Unique URIs for Government Linked Data • URI Template: 'http://' BASE '/' 'id' '/' ORG '/' CATEGORY ( '/' TOKEN )+ • States and Territories • Owner • federal • Suggested • http://BASE/id/us/state/NAME • Example • http://logd.tw.rpi.edu/id/us/state/Vermont http://logd.tw.rpi.edu/instance-hub-uri-design

  16. title date body bold1 bold2 XML (Extensible Markup Language) • a textual data format for the representation of arbitrary data structures over the Internet • both human-readable and machine-readable <title> W3C Demonstrates … </title> <date> 12 February 2013 </date> <body> W3C invites media, analysts, and other attendees of Mobile World Congress … </body> title date body bold1 bold2 Content Structure Presentation Concept Related Recommendations XML XSLT XSL-fo XPath DTD XML Schema http://en.wikipedia.org/wiki/Xml

  17. Data Representation of XML • Various ways to represent data using XML • Myungjin Lee is Hye-jin’s husband. • We need a method to represent data on abstract level. <conjugalrelation> <husband>Myungjin Lee</husband> <wife>Hye-jin Han</wife> </conjugalrelation> <conjugalrelation husband=“Myungjin Lee”> <wife>Hye-jin Han</wife> </conjugalrelation> <conjugalrelation husband=“Myungjin Lee” wife=“Hye-jin Han” />

  18. RDF (Resource Description Framework) • a general method for conceptual description or modeling of information that is implemented in web resources, using a variety of syntax formats • MyungjinLee is Hye-jin’s husband. hasWife http://en.wikipedia.org/wiki/Resource_Description_Framework

  19. Data Representation of RDF hasWife http://semantics.kr/rel/hasWife http://semantics.kr/myungjinlee http://semantics.kr/hye-jinhan Subject URI reference Predicate URI reference Object URI reference or Literal Triple

  20. RDF Example http://www.cars.com/car#Gasoline http://www.cars.com/car#fuel http://www.cars.com/car#AWD http://www.cars.com/car#GDI http://www.cars.com/car#engine http://www.cars.com/car#drivetrain http://www.cars.com/car#doors http://www.cars.com/car#wheelbase http://www.cars.com/car#A6 4 115” http://www.cars.com/car#body_style http://www.cars.com/car#transmission http://www.cars.com/car#Sedan http://www.cars.com/car#Auto_8-Speed http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://www.cars.com/car#Car

  21. RDF Serialization • N-Triples • RDF Test Cases, W3C Recommendation, 10 February 2004 • a line-based, plain text serialization format for storing and transmitting RDF data • Notation 3 (N3) • a shorthand non-XML serialization of RDF models, designed with human-readability in mind • much more compact and readable than XML RDF notation • Turtle (Terse RDF Triple Language) • W3C Candidate Recommendation, 19 February 2013 • a format for expressing data in the Resource Description Framework (RDF) data model • a subset of Notation3 (N3) language, and a superset of the minimal N-Triples format • RDF/XML • W3C Recommendation, 10 February 2004 • an XML syntax for writing down and exchanging RDF graphs http://en.wikipedia.org/wiki/N-Triples http://en.wikipedia.org/wiki/Notation3 http://en.wikipedia.org/wiki/Turtle_(syntax)

  22. N-Triple <http://en.wikipedia.org/wiki/Tony_Benn> <http://purl.org/dc/elements/1.1/title> "Tony Benn" . <http://en.wikipedia.org/wiki/Tony_Benn> <http://purl.org/dc/elements/1.1/publisher> "Wikipedia" . N3 @prefix dc: <http://purl.org/dc/elements/1.1/>. <http://en.wikipedia.org/wiki/Tony_Benn> dc:title "Tony Benn"; dc:publisher "Wikipedia". RDF/XML <rdf:RDFxmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"> <rdf:Descriptionrdf:about="http://en.wikipedia.org/wiki/Tony_Benn"> <dc:title>Tony Benn</dc:title> <dc:publisher>Wikipedia</dc:publisher> </rdf:Description> </rdf:RDF> Turtle @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix dc: <http://purl.org/dc/elements/1.1/> . @prefix ex: <http://example.org/stuff/1.0/> . <http://www.w3.org/TR/rdf-syntax-grammar> dc:title "RDF/XML Syntax Specification (Revised)" ; ex:editor [ ex:fullname"Dave Beckett"; ex:homePage <http://purl.org/net/dajobe/> ] .

  23. http://www.w3.org/TR/rdf11-concepts/

  24. RDF 1.0 vs RDF 1.1

  25. Recommendations of RDF http://www.w3.org/standards/techs/rdf#w3c_all

  26. RDF Schema • W3C Recommendation, 10 February 2004 • to define classes and properties that may be used to describe classes, properties and other resources • RDF Schema allows • Definition of Classes • Definition of Properties and Restrictions • Definition of Hierarchies http://www.slideshare.net/lysander07/openhpi-22

  27. RDF Schema Example TBox - terminological component car:Vehicle rdf:Property rdf:type rdfs:Class rdfs:subClassOf rdf:type car:Car car:body_style rdf:type rdfs:domain rdf:type rdfs:range car:A6 car:Sedan car:Style car:body_style rdf:type ABox - assertion component

  28. RDF Semantics • to provide a formal meaning based on a model-theoretic semantics in its abstract syntax <x, y> is in IEXT(I(rdfs:subClassOf)) if and only if x and y are in IC and ICEXT(x) is a subset of ICEXT(y) car:Vehicle rdfs:subClassOf car:Car rdf:type rdf:type car:A6

  29. SPARQL • Why do we need a query language for RDF? • Why de we need a query language for RDB? • to get to the knowledge from RDF • SPARQL Protocol and RDF Query Language • to retrieve and manipulate data stored in Resource Description Framework format • to use SPARQL via HTTP http://www.slideshare.net/lysander07/openhpi-semweb03part1

  30. SPARQL Example PREFIX foaf: <http://xmlns.com/foaf/0.1/> SELECT ?name ?email WHERE { ?person a foaf:Person. ?person foaf:name?name. ?person foaf:mbox ?email. } RDF Knowledge Base

  31. SPARQL Query Forms • SELECT query • Used to extract raw values from a SPARQL endpoint, the results are returned in a table format. • CONSTRUCT query • Used to extract information from the SPARQL endpoint and transform the results into valid RDF. • ASK query • Used to provide a simple True/False result for a query on a SPARQL endpoint. • DESCRIBE query • Used to extract an RDF graph from the SPARQL endpoint, the contents of which is left to the endpoint to decide based on what the maintainer deems as useful information. http://en.wikipedia.org/wiki/SPARQL

  32. OWL (Web Ontology Language) • knowledge representation languages for authoring ontologies • If you need more expressiveness  OWL • such as, ∩ = Ø Man Woman descendant descendant Person Person Person Genre type descendant hasGenre _01 Action 1:1 Husband Wife subClassOf ActionMovie

  33. What more do we need? SPARQL Linked Data Platform Linked Data Service HTML HTML HTML RDFa RDBMS Triple Store + RDF Knowledge R2RML GRDDL

  34. http://www.w3.org/TR/r2rml/ R2RML • RDB to RDF Mapping Language • W3C Recommendation 27 September 2012 • a language for expressing customized mappings from relational databases to RDF datasets RDB R2RML @prefix rr: <http://www.w3.org/ns/r2rml#>. @prefix ex: <http://example.com/ns#>. <#TriplesMap1> rr:logicalTable [ rr:tableName "EMP" ]; rr:subjectMap [ rr:template "http://data.example.com/employee/{EMPNO}"; rr:classex:Employee; ]; rr:predicateObjectMap [ rr:predicateex:name; rr:objectMap [ rr:column "ENAME" ]; ]. Result <http://data.example.com/employee/7369> rdf:typeex:Employee. <http://data.example.com/employee/7369> ex:name "SMITH".

  35. Linked Data Platform • A set of best practices and simple approach for a read-write Linked Data architecture, based on HTTP access to web resources that describe their state using RDF • W3C Working Draft 25 October 2012 http://www.w3.org/TR/ldp/

  36. RDFa(the Resource Description Framework in attributes) • W3C Recommendation, 07 June 2012 • to express machine-readable data in Web documents like HTML, SVG, and XML Example<p vocab="http://schema.org/" resource="#manu" typeof="Person"> My name is <span property="name">Manu Sporny</span> and you can give me a ring via <span property="telephone">1-800-555-0199</span>. <imgproperty="image"src="http://manu.sporny.org/images/manu.png" /> </p> http://www.w3.org/TR/xhtml-rdfa-primer/

  37. http://www.w3.org/TR/grddl/ GRDDL (Gleaning Resource Descriptions from Dialects of Languages) • a mechanism and markup format for Gleaning Resource Descriptions from Dialects of Languages to obtain RDF triples out of XML documents, including XHTML HTML <html xmlns:grddl='http://www.w3.org/2003/g/data-view#' grddl:transformation="glean_title.xsl getAuthor.xsl"> <head> <title>Are You Experienced?</title> </head> ... glean_title.xsl <xsl:stylesheet version="1.0"> <xsl:template match="/"> <rdf:RDFxmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <rdf:Descriptionrdf:about="{$subject}"> <dc:title> <xsl:value-of select="/html:html/html:head/html:title"/> </dc:title> </rdf:Description> </rdf:RDF> </xsl:template> </xsl:stylesheet> RDF <rdf:RDF> <rdf:Descriptionrdf:about=""> <dc:title>Are You Experienced?</dc:title> </rdf:Description> </rdf:RDF>

  38. Jena Platform SPARQL Fuseki ARQ & LARQ Linked Data Service Jena API HTML HTML HTML RDBMS Triple Store TDB & SDB http://jena.apache.org/

  39. Openlink Virtuoso • a middleware and database engine hybrid that combines the functionality of a traditional RDBMS, ORDBMS, RDF, XML, etc. • Relational Data Management • RDF Data Management • XML Data Management • Free Text Content Management & Full Text Indexing • Document Web Server • Linked Data Server • Web Application Server • Web Services Deployment (SOAP or REST) http://virtuoso.openlinksw.com/

  40. Openlink Virtuoso Coverage SPARQL SPARQL Server Linked Data Service HTML HTML HTML RDBMS Triple Store Sponger Storage and Inference

  41. http://lod-cloud.net/ The Linking Open Data cloud diagram Linked Data & Semantic Web Technology

  42. User Generated Content Media Publications Government Geographic Life Sciences Cross-Domain Linked Data & Semantic Web Technology http://www.slideshare.net/lysander07/13-semantic-web-technologies-linked-data-semantic-search

  43. KDATA (Linked Data for Korea) Linked Data & Semantic Web Technology http://kdata.kr/index.jsp

  44. SPARQL select ?s where { ?s rdf:type <http://data.kdata.kr/class/NationalTreasure> . ?s rdfs:label "남대문" . } HTML http://data.kdata.kr/resource/Namdaemun <rdf:RDF> <rdf:Descriptionrdf:about="http://data.kdata.kr/data/Namdaemun?output=rdfxml"> <rdfs:label>RDF description of Namdaemun</rdfs:label> <foaf:primaryTopic> <kdc:StateDesignatedHeritagerdf:about="http://data.kdata.kr/resource/Namdaemun"> <rdfs:label>남대문</rdfs:label> <rdfs:label>숭례문</rdfs:label> <foaf:depictionrdf:resource="20060227132556895000.jpg"/> <owl:sameAsrdf:resource="http://dbpedia.org/resource/Namdaemun"/> ... </rdf:RDF> RDF

  45. Thanks for your attention. Dr. Myungjin Lee e-Mail : mjlee@li-st.com Twitter : http://twitter.com/MyungjinLee Facebook : http://www.facebook.com/mjinlee SlideShare : http://www.slideshare.net/onlyjiny/

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