2. Linked Data is a set of best practices to publish and interlink data on the web
3. Linked Data Principles Use URIs as names for things Use 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.
5. 1) Use URIs as names for things Uniform Resource Identifiers identify real world objects and abstract concepts Not only web documents and digital content People, places, locations, my car Know somebody, from somewhere
6. 1) Use URIs as names for things http://juansequeda.com/foaf.rdf#me http://www.w3.org/People/Berners-Lee/card#i http://xmlns.com/foaf/0.1/knows
7. 1) Use URIs as names for things http://juansequeda.com/foaf.rdf#me Identifies the person http://juansequeda.com/foaf.rdf Identifies 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 mechanism Linked Data only uses HTTP URIs URI: unique name HTTP URI: universal means of access to the URI HTTP URIs should be dereferencable
30. Minting HTTP URIs If you own the domain name and run a web server at that location, mint URIs in this namespace I own the domain mycompany.com I run a webserverhttp://mycompany.com I now can mint URIs in this namespace: http://mycompany.com/person/Juan-Sequeda
31. Create Cool URIs If you don’t control a namespace, don’t misuse it http://www.imdb.com/title Avoid implementation details http://foo.mycompany.com:8080/person.php?id=123&format=rdf Use Natural Keys within URI http://mycompany.com/person/Juan-Sequeda http://mycompany.com/person/123
32. Three different URIs URI for the real world object (non-information resource) http://dbpedia.org/resource/London http://id.mycompany.com/person/Juan-Sequeda http://mycompany.com/person/Juan-Sequeda http://www.juansequeda.com/foaf.rdf#me URI for the HTML document (information resource) that describes the real world object http://dbpedia.org/page/London http://pages.mycompany.com/person/Juan-Sequeda http://mycompany.com/person/Juan-Sequeda.html URI for the RDF document (information resource) that describes the real world object http://dbpedia.org/data/London http://data.mycompany.com/Juan-Sequeda http://mycompany.com/person/Juan-Sequeda.rdf http://www.juansequeda.com/foaf.rdf
34. 3) Provide useful information How do we provide useful information in document form on the web? HTML How do we provide useful information in data form on the web RDF Different ways of serializing RDF RDF/XML RDFa N3 turtle
35. RDF subject – predicate – object Coldplay is the artist of Viva la Vida Coldplay is the artist of Viva la Vida http://dbpedia.org/resource/Coldplay 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 set Semantic Sitemaps voiD (Vocabulary of Interlinked Datasets) Provenance Metadata Licenses Information
42. Vocabularies (or Schemas or Ontologies) Create your own using Simple Knowledge Organization Systems (SKOS) Taxonomy RDF Vocabulary Description Language (RDF Schema) Light weight vocabularies Web Ontological Language (OWL) Highly expressive and capable of inferencing
43. Vocabularies (or Schemas or Ontologies) Reuse vocabularies Dublin Core: metadata attributes Friend of a Friend (FOAF): persons and relationships Semantically Interlinked Online Communities (SIOC): describing users, posts, blogs, etc Description of a Project (DOAP) Music Ontology Programmes Ontology: TV and radio programs Good Relations: describing products and services Review Vocabulary Basic Geo (WGS84) Vocabulary
45. 4) Include links to other things Set external RDF links into other data sources on the Web Subject of the triple is in the namespace of one data set Object of the triple is a URI in the namespace of another data set Connect siloed data islands Enable discovery
46. 4) Include links to other things Relationship 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 domain Is it widely used? owl:sameAs foaf:knows foaf:based_near … If you create your own, relate it to a widely used predicate
48. How to create the links? Manually Works for small and static data sets I want to find another URI that identifies the same real object that I have Sindice and Falcons provide index of URIs by keyword (Semi) Automatic Record Linkage/Identity Resolution/Co-reference Silk: http://www4.wiwiss.fu-berlin.de/bizer/silk/ LIMES: http://aksw.org/Projects/limes
