Creating Linked Data 2/5 Semtech2011
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This document discusses Linked Data and the best practices for publishing and interlinking data on the web. It covers four main principles: 1) Use URIs as names for things and identify real-world objects with HTTP URIs. 2) Use HTTP URIs so that people can look up those names by dereferencing the URIs. 3) Provide useful RDF information when URIs are dereferenced, using formats like RDF/XML, RDFa, N3, or Turtle. 4) Include links to other URIs to discover more related things and connect isolated data silos. This allows data to be interlinked on the Web.
Creating Linked Data 2/5 Semtech2011
- 1. Creating Linked DataJuan F. Sequeda Semantic Technology ConferenceJune 2011
- 2. Linked Data is a set of best practices to publish and interlink data on the web
- 3. Linked Data PrinciplesUse URIs as names for thingsUse HTTP URIs so that people can look up (dereference) those names.When someone looks up a URI, provide useful information.Include links to other URIs so that they can discover more things.
- 4. 1) Use URIs as names for things
- 5. 1) Use URIs as names for thingsUniform Resource Identifiers identify real world objects and abstract conceptsNot only web documents and digital contentPeople, places, locations, my carKnow somebody, from somewhere
- 6. 1) Use URIs as names for thingshttp://juansequeda.com/foaf.rdf#mehttp://www.w3.org/People/Berners-Lee/card#ihttp://xmlns.com/foaf/0.1/knows
- 7. 1) Use URIs as names for thingshttp://juansequeda.com/foaf.rdf#meIdentifies the personhttp://juansequeda.com/foaf.rdfIdentifies an RDF document
- 8. 2) Use HTTP URIs so that people can look up (dereference) those names.
- 9. 2) Use HTTP URIs so that people can look up (dereference) those names.HTTP protocol is the Web’s universal access mechanismLinked Data only uses HTTP URIsURI: unique nameHTTP URI: universal means of access to the URIHTTP URIs should be dereferencable
- 16. What’s with the redirection?
- 28. RDFa<html>… <div xmlns:dc=“http://purl.org/dc/elements/1.1/”> <h2 property=“dc:title”>The trouble with Bob</h2> <h3 property=“dc:creator”>Alice</h3> …. </div>…</html>
- 30. Minting HTTP URIsIf you own the domain name and run a web server at that location, mint URIs in this namespaceI own the domain mycompany.comI run a webserverhttp://mycompany.comI now can mint URIs in this namespace:http://mycompany.com/person/Juan-Sequeda
- 31. Create Cool URIsIf you don’t control a namespace, don’t misuse ithttp://www.imdb.com/titleAvoid implementation detailshttp://foo.mycompany.com:8080/person.php?id=123&format=rdfUse Natural Keys within URIhttp://mycompany.com/person/Juan-Sequedahttp://mycompany.com/person/123
- 32. Three different URIsURI for the real world object (non-information resource)http://dbpedia.org/resource/Londonhttp://id.mycompany.com/person/Juan-Sequedahttp://mycompany.com/person/Juan-Sequedahttp://www.juansequeda.com/foaf.rdf#meURI for the HTML document (information resource) that describes the real world objecthttp://dbpedia.org/page/Londonhttp://pages.mycompany.com/person/Juan-Sequedahttp://mycompany.com/person/Juan-Sequeda.htmlURI for the RDF document (information resource) that describes the real world objecthttp://dbpedia.org/data/Londonhttp://data.mycompany.com/Juan-Sequedahttp://mycompany.com/person/Juan-Sequeda.rdfhttp://www.juansequeda.com/foaf.rdf
- 33. 3) Provide useful information
- 34. 3) Provide useful informationHow do we provide useful information in document form on the web? HTMLHow do we provide useful information in data form on the web RDFDifferent ways of serializing RDFRDF/XMLRDFaN3turtle
- 35. RDFsubject – predicate – objectColdplay is the artist of Viva la VidaColdplay is the artist of Viva la Vidahttp://dbpedia.org/resource/Coldplayhttp://dbpedia.org/ontology/artisthttp://dbpedia.org/resource/Viva_la_Vida
- 36. prefix dbpedia-owl: <http://dbpedia.org/ontology/>prefix foaf: <http://xmlns.com/foaf/0.1/>prefix dbprop: <http://dbpedia.org/property/>prefix geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>51.507778-0.128056geo:longgeo:lathttp://dbpedia.org/resource/Londondbprop:originhttp://dbpedia.org/resource/Coldplaydbpedia-owl:artistfoaf:namehttp://dbpedia.org/resource/Viva_la_Vida“Coldplay”
- 37. ntriples<http://dbpedia.org/resource/Coldplay> <http://dbpedia.org/ontology/artist> <http://dbpedia.org/resource/Viva_la_Vida> .<http://dbpedia.org/resource/Coldplay> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Band> .RDF/XML<?xml version="1.0" encoding="utf-8"?><rdf:RDFxmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><dbpedia-owl:Bandxmlns:dbpedia-owl="http://dbpedia.org/ontology/"rdf:about="http://dbpedia.org/resource/Coldplay"><dbpedia-owl:artistrdf:resource="http://dbpedia.org/resource/Viva_la_Vida"/> </dbpedia-owl:Band></rdf:RDF>turtle@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .<http://dbpedia.org/resource/Coldplay> a <http://dbpedia.org/ontology/Band> ;<http://dbpedia.org/ontology/artist> <http://dbpedia.org/resource/Viva_la_Vida> .
- 38. HTML<div>My name is Bob Smith, but people call me Smithy. Here is my home page:<a href="http://www.example.com">www.example.com</a>.I live in Albuquerque, NM and work as an engineer at ACME Corp.My friends:<a href="http://darryl-blog.example.com">Darryl</a>,<a href="http://edna-blog.example.com">Edna</a></div>
- 39. RDFa (RDF in HTML)<div xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Person"> My name is <span property="v:name">Bob Smith</span>, but people call me <span property="v:nickname">Smithy</span>. Here is my homepage: <a href="http://www.example.com" rel="v:url">www.example.com</a>. I live in <span rel="v:address"> <span typeof="v:Address"> <span property="v:locality">Albuquerque</span>, <span property="v:region">NM</span> </span> </span> and work as an <span property="v:title">engineer</span> at <span property="v:affiliation">ACME Corp</span>. My friends: <a href="http://darryl-blog.example.com" rel="v:friend">Darryl</a>, <a href="http://edna-blog.example.com" rel="v:friend">Edna</a></div>
- 40. What to publish?Literal Triples<http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <foaf:name> “Coldplay” Outgoing Links<http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <owl:sameAs> <http://dbpedia.org/resource/Coldplay>Incoming Link<http://www.bbc.co.uk/music/artists/18690715-59fa-4e4d-bcf3-8025cf1c23e0#artist> <mo:member_of> <http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist>
- 41. What to publish?Description of the data setSemantic SitemapsvoiD (Vocabulary of Interlinked Datasets)Provenance MetadataLicenses Information
- 42. Vocabularies (or Schemas or Ontologies)Create your own usingSimple Knowledge Organization Systems (SKOS)TaxonomyRDF Vocabulary Description Language (RDF Schema)Light weight vocabulariesWeb Ontological Language (OWL)Highly expressive and capable of inferencing
- 43. Vocabularies (or Schemas or Ontologies)Reuse vocabulariesDublin Core: metadata attributesFriend of a Friend (FOAF): persons and relationshipsSemantically Interlinked Online Communities (SIOC): describing users, posts, blogs, etcDescription of a Project (DOAP)Music OntologyProgrammes Ontology: TV and radio programsGood Relations: describing products and servicesReview VocabularyBasic Geo (WGS84) Vocabulary
- 44. 4) Include links to other things
- 45. 4) Include links to other thingsSet external RDF links into other data sources on the WebSubject of the triple is in the namespace of one data setObject of the triple is a URI in the namespace of another data setConnect siloed data islandsEnable discovery
- 46. 4) Include links to other thingsRelationship Links<http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <http://xmlns.com/foaf/0.1/based_near> <http://dbpedia.org/resource/London>Identity Link<http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <http://www.w3.org/2002/07/owl#sameAs> <http://dbpedia.org/resource/Coldplay> Vocabulary Links<http://purl.org/ontology/mo/image> <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> <http://xmlns.com/foaf/0.1/depiction>
- 47. Which predicate for linking to choose?Depends on your domainIs it widely used?owl:sameAsfoaf:knowsfoaf:based_near…If you create your own, relate it to a widely used predicate
- 48. How to create the links?ManuallyWorks for small and static data setsI want to find another URI that identifies the same real object that I haveSindice and Falcons provide index of URIs by keyword(Semi) AutomaticRecord Linkage/Identity Resolution/Co-referenceSilk: http://www4.wiwiss.fu-berlin.de/bizer/silk/LIMES: http://aksw.org/Projects/limes