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Creating Linked Data<br />Juan F. Sequeda	<br />Semantic Technology Conference<br />June 2011<br />
Linked Data is a set of best practices to publish and interlink data on the web<br />
Linked Data Principles<br />Use URIs as names for things<br />Use HTTP URIs so that people can look up (dereference) those...
1) Use URIs as names for things<br />
1) Use URIs as names for things<br />Uniform Resource Identifiers identify real world objects and abstract concepts<br />N...
1) Use URIs as names for things<br />http://juansequeda.com/foaf.rdf#me<br />http://www.w3.org/People/Berners-Lee/card#i<b...
1) Use URIs as names for things<br />http://juansequeda.com/foaf.rdf#me<br />Identifies the person<br />http://juansequeda...
2) Use HTTP URIs so that people can look up (dereference) those names.<br />
2) Use HTTP URIs so that people can look up (dereference) those names.<br />HTTP protocol is the Web’s universal access me...
Dereference a URI?<br />
What’s with the redirection?<br />
RDFa<br /><html><br />…<br />	<div xmlns:dc=“http://purl.org/dc/elements/1.1/”><br />		<h2 property=“dc:title”>The trouble...
Minting HTTP URIs<br />If you own the domain name and run a web server at that location, mint URIs in this namespace<br />...
Create Cool URIs<br />If you don’t control a namespace, don’t misuse it<br />http://www.imdb.com/title<br />Avoid implemen...
Three different URIs<br />URI for the real world object (non-information resource)<br />http://dbpedia.org/resource/London...
3) Provide useful information<br />
3) Provide useful information<br />How do we provide useful information in document form on the web?  HTML<br />How do we...
RDF<br />subject – predicate – object<br />Coldplay is the artist of Viva la Vida<br />Coldplay is the artist of Viva la V...
prefix dbpedia-owl: <http://dbpedia.org/ontology/><br />prefix foaf: <http://xmlns.com/foaf/0.1/><br />prefix dbprop: <htt...
ntriples<br /><http://dbpedia.org/resource/Coldplay> <http://dbpedia.org/ontology/artist> <http://dbpedia.org/resource/Viv...
HTML<br /><div><br />My name is Bob Smith, but people call me Smithy. Here is my home page:<br /><a href="http://www.examp...
RDFa (RDF in HTML)<br /><div xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Person"><br />   My name is <span proper...
What to publish?<br />Literal Triples<br /><http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist...
What to publish?<br />Description of the data set<br />Semantic Sitemaps<br />voiD (Vocabulary of Interlinked Datasets)<br...
Vocabularies (or Schemas or  Ontologies)<br />Create your own using<br />Simple Knowledge Organization Systems (SKOS)<br /...
Vocabularies (or Schemas or  Ontologies)<br />Reuse vocabularies<br />Dublin Core: metadata attributes<br />Friend of a Fr...
4) Include links to other things<br />
4) Include links to other things<br />Set external RDF links into other data sources on the Web<br />Subject of the triple...
4) Include links to other things<br />Relationship Links<br /><http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-...
Which predicate for linking to choose?<br />Depends on your domain<br />Is it widely used?<br />owl:sameAs<br />foaf:knows...
How to create the links?<br />Manually<br />Works for small and static data sets<br />I want to find another URI that iden...
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Creating Linked Data 2/5 Semtech2011

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Transcript of "Creating Linked Data 2/5 Semtech2011"

  1. 1. Creating Linked Data<br />Juan F. Sequeda <br />Semantic Technology Conference<br />June 2011<br />
  2. 2. Linked Data is a set of best practices to publish and interlink data on the web<br />
  3. 3. Linked Data Principles<br />Use URIs as names for things<br />Use HTTP URIs so that people can look up (dereference) those names.<br />When someone looks up a URI, provide useful information.<br />Include links to other URIs so that they can discover more things.<br />
  4. 4. 1) Use URIs as names for things<br />
  5. 5. 1) Use URIs as names for things<br />Uniform Resource Identifiers identify real world objects and abstract concepts<br />Not only web documents and digital content<br />People, places, locations, my car<br />Know somebody, from somewhere<br />
  6. 6. 1) Use URIs as names for things<br />http://juansequeda.com/foaf.rdf#me<br />http://www.w3.org/People/Berners-Lee/card#i<br />http://xmlns.com/foaf/0.1/knows<br />
  7. 7. 1) Use URIs as names for things<br />http://juansequeda.com/foaf.rdf#me<br />Identifies the person<br />http://juansequeda.com/foaf.rdf<br />Identifies an RDF document<br />
  8. 8. 2) Use HTTP URIs so that people can look up (dereference) those names.<br />
  9. 9. 2) Use HTTP URIs so that people can look up (dereference) those names.<br />HTTP protocol is the Web’s universal access mechanism<br />Linked Data only uses HTTP URIs<br />URI: unique name<br />HTTP URI: universal means of access to the URI<br />HTTP URIs should be dereferencable<br />
  10. 10. Dereference a URI?<br />
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  12. 12.
  13. 13.
  14. 14.
  15. 15.
  16. 16. What’s with the redirection?<br />
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  18. 18.
  19. 19.
  20. 20.
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  24. 24.
  25. 25.
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  27. 27.
  28. 28. RDFa<br /><html><br />…<br /> <div xmlns:dc=“http://purl.org/dc/elements/1.1/”><br /> <h2 property=“dc:title”>The trouble with Bob</h2><br /> <h3 property=“dc:creator”>Alice</h3><br /> ….<br /> </div><br />…<br /></html><br />
  29. 29.
  30. 30. Minting HTTP URIs<br />If you own the domain name and run a web server at that location, mint URIs in this namespace<br />I own the domain mycompany.com<br />I run a webserverhttp://mycompany.com<br />I now can mint URIs in this namespace:<br />http://mycompany.com/person/Juan-Sequeda<br />
  31. 31. Create Cool URIs<br />If you don’t control a namespace, don’t misuse it<br />http://www.imdb.com/title<br />Avoid implementation details<br />http://foo.mycompany.com:8080/person.php?id=123&format=rdf<br />Use Natural Keys within URI<br />http://mycompany.com/person/Juan-Sequeda<br />http://mycompany.com/person/123<br />
  32. 32. Three different URIs<br />URI for the real world object (non-information resource)<br />http://dbpedia.org/resource/London<br />http://id.mycompany.com/person/Juan-Sequeda<br />http://mycompany.com/person/Juan-Sequeda<br />http://www.juansequeda.com/foaf.rdf#me<br />URI for the HTML document (information resource) that describes the real world object<br />http://dbpedia.org/page/London<br />http://pages.mycompany.com/person/Juan-Sequeda<br />http://mycompany.com/person/Juan-Sequeda.html<br />URI for the RDF document (information resource) that describes the real world object<br />http://dbpedia.org/data/London<br />http://data.mycompany.com/Juan-Sequeda<br />http://mycompany.com/person/Juan-Sequeda.rdf<br />http://www.juansequeda.com/foaf.rdf<br />
  33. 33. 3) Provide useful information<br />
  34. 34. 3) Provide useful information<br />How do we provide useful information in document form on the web?  HTML<br />How do we provide useful information in data form on the web  RDF<br />Different ways of serializing RDF<br />RDF/XML<br />RDFa<br />N3<br />turtle<br />
  35. 35. RDF<br />subject – predicate – object<br />Coldplay is the artist of Viva la Vida<br />Coldplay is the artist of Viva la Vida<br />http://dbpedia.org/resource/Coldplay<br />http://dbpedia.org/ontology/artist<br />http://dbpedia.org/resource/Viva_la_Vida<br />
  36. 36. prefix dbpedia-owl: <http://dbpedia.org/ontology/><br />prefix foaf: <http://xmlns.com/foaf/0.1/><br />prefix dbprop: <http://dbpedia.org/property/><br />prefix geo: <http://www.w3.org/2003/01/geo/wgs84_pos#><br />51.507778<br />-0.128056<br />geo:long<br />geo:lat<br />http://dbpedia.org/resource/London<br />dbprop:origin<br />http://dbpedia.org/resource/Coldplay<br />dbpedia-owl:artist<br />foaf:name<br />http://dbpedia.org/resource/Viva_la_Vida<br />“Coldplay”<br />
  37. 37. ntriples<br /><http://dbpedia.org/resource/Coldplay> <http://dbpedia.org/ontology/artist> <http://dbpedia.org/resource/Viva_la_Vida> .<br /><http://dbpedia.org/resource/Coldplay> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/Band> .<br />RDF/XML<br /><?xml version="1.0" encoding="utf-8"?><br /><rdf:RDFxmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><br /><dbpedia-owl:Bandxmlns:dbpedia-owl="http://dbpedia.org/ontology/"<br />rdf:about="http://dbpedia.org/resource/Coldplay"><br /><dbpedia-owl:artistrdf:resource="http://dbpedia.org/resource/Viva_la_Vida"/> </dbpedia-owl:Band><br /></rdf:RDF><br />turtle<br />@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .<br /><http://dbpedia.org/resource/Coldplay><br /> a <http://dbpedia.org/ontology/Band> ;<br /><http://dbpedia.org/ontology/artist> <http://dbpedia.org/resource/Viva_la_Vida> .<br />
  38. 38. HTML<br /><div><br />My name is Bob Smith, but people call me Smithy. Here is my home page:<br /><a href="http://www.example.com">www.example.com</a>.<br />I live in Albuquerque, NM and work as an engineer at ACME Corp.<br />My friends:<br /><a href="http://darryl-blog.example.com">Darryl</a>,<br /><a href="http://edna-blog.example.com">Edna</a><br /></div><br />
  39. 39. RDFa (RDF in HTML)<br /><div xmlns:v="http://rdf.data-vocabulary.org/#" typeof="v:Person"><br /> My name is <span property="v:name">Bob Smith</span>,<br /> but people call me <span property="v:nickname">Smithy</span>.<br /> Here is my homepage:<br /> <a href="http://www.example.com" rel="v:url">www.example.com</a>.<br /> I live in<br /> <span rel="v:address"><br /> <span typeof="v:Address"><br /> <span property="v:locality">Albuquerque</span>,<br /> <span property="v:region">NM</span><br /> </span><br /> </span><br /> and work as an <span property="v:title">engineer</span><br /> at <span property="v:affiliation">ACME Corp</span>.<br /> My friends:<br /> <a href="http://darryl-blog.example.com" rel="v:friend">Darryl</a>,<br /> <a href="http://edna-blog.example.com" rel="v:friend">Edna</a><br /></div><br />
  40. 40. What to publish?<br />Literal Triples<br /><http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <br /> <foaf:name> <br /> “Coldplay” <br />Outgoing Links<br /><http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <br /> <owl:sameAs> <br /> <http://dbpedia.org/resource/Coldplay><br />Incoming Link<br /><http://www.bbc.co.uk/music/artists/18690715-59fa-4e4d-bcf3-8025cf1c23e0#artist> <br /> <mo:member_of> <br /> <http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist> <br />
  41. 41. What to publish?<br />Description of the data set<br />Semantic Sitemaps<br />voiD (Vocabulary of Interlinked Datasets)<br />Provenance Metadata<br />Licenses Information<br />
  42. 42. Vocabularies (or Schemas or Ontologies)<br />Create your own using<br />Simple Knowledge Organization Systems (SKOS)<br />Taxonomy<br />RDF Vocabulary Description Language (RDF Schema)<br />Light weight vocabularies<br />Web Ontological Language (OWL)<br />Highly expressive and capable of inferencing<br />
  43. 43. Vocabularies (or Schemas or Ontologies)<br />Reuse vocabularies<br />Dublin Core: metadata attributes<br />Friend of a Friend (FOAF): persons and relationships<br />Semantically Interlinked Online Communities (SIOC): describing users, posts, blogs, etc<br />Description of a Project (DOAP)<br />Music Ontology<br />Programmes Ontology: TV and radio programs<br />Good Relations: describing products and services<br />Review Vocabulary<br />Basic Geo (WGS84) Vocabulary<br />
  44. 44. 4) Include links to other things<br />
  45. 45. 4) Include links to other things<br />Set external RDF links into other data sources on the Web<br />Subject of the triple is in the namespace of one data set<br />Object of the triple is a URI in the namespace of another data set<br />Connect siloed data islands<br />Enable discovery<br />
  46. 46. 4) Include links to other things<br />Relationship Links<br /><http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist><br /> <http://xmlns.com/foaf/0.1/based_near> <http://dbpedia.org/resource/London><br />Identity Link<br /><http://www.bbc.co.uk/music/artists/cc197bad-dc9c-440d-a5b5-d52ba2e14234#artist><br /> <http://www.w3.org/2002/07/owl#sameAs><br /> <http://dbpedia.org/resource/Coldplay> <br />Vocabulary Links<br /><http://purl.org/ontology/mo/image><br /> <http://www.w3.org/2000/01/rdf-schema#subPropertyOf><br /> <http://xmlns.com/foaf/0.1/depiction> <br />
  47. 47. Which predicate for linking to choose?<br />Depends on your domain<br />Is it widely used?<br />owl:sameAs<br />foaf:knows<br />foaf:based_near<br />…<br />If you create your own, relate it to a widely used predicate<br />
  48. 48. How to create the links?<br />Manually<br />Works for small and static data sets<br />I want to find another URI that identifies the same real object that I have<br />Sindice and Falcons provide index of URIs by keyword<br />(Semi) Automatic<br />Record Linkage/Identity Resolution/Co-reference<br />Silk: http://www4.wiwiss.fu-berlin.de/bizer/silk/<br />LIMES: http://aksw.org/Projects/limes<br />
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