Introduction to Linked Data

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Very brief introduction to Linked Data for the SSSW 2013 summer school. Preparing for the practical exercises. See http://sssw.org/2013/learning-resources/

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  • Graph from aa100
  • Introduction to Linked Data

    1. 1. Linked Data Introduction @sssw2013 - #sssw2013
    2. 2. Data
    3. 3. Linked Data
    4. 4. The Semantic Web
    5. 5. Open University Website Open University VLE KMi Website Mathieu’s Homepage Mathieu’s List of Publications Mathieu’s Twitter M366 Course page Person: Mathieu Publication: Pub1 Organisation: The Open University Course: M366 Country: Belgium Book: Mechatronics author workFor availableIn offers setBook The Web of Linked DataThe Web
    6. 6. Basis • URIs and Web based information access • RDF, graph-based data modelling • SPARQL, querying and updating over web endpoints
    7. 7. URIs Example: http://data.open.ac.uk/course/aa100 An anchor for linking Let’s say you took this course. You – took  this URI An identifier for a data entity Here, the a course offered by the Open University An access point to representation(s) of the data entity In possibly different formats…
    8. 8. RDF – graph data model for the Web http://data.open.ac.uk/course/aa100 “The arts past and present” http://data.open.ac.uk/saou/ontology#undergraduate http://purl.org/vocab/aiiso/schema#Module http://data.open.ac.uk/topic/arts_and_humanities http://sws.geonames.org/3017382/ “France” dc:title rdf:label rdf:type dc:subject courseLevel geo:latgeo:long
    9. 9. RDF+XML <?xml version="1.0" encoding="UTF-8"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <rdf:Description rdf:about="http://data.open.ac.uk/course/aa100"> <title xmlns="http://purl.org/dc/terms/" rdf:datatype="http://www.w3.org/2001/XMLSchema#string">The arts past and present</title> <courseLevel xmlns="http://data.open.ac.uk/saou/ontology#" rdf:resource="http://data.open.ac.uk/saou/ontology#undergraduate"/> <isSimilarTo xmlns="http://purl.org/goodrelations/v1#" rdf:resource="http://data.open.ac.uk/course/a200"/> <hasBook xmlns="http://data.open.ac.uk/saou/ontology#" rdf:resource="http://data.open.ac.uk/book/9780571195473"/> <location xmlns="http://purl.org/net/mlo/" rdf:resource="http://sws.geonames.org/2634895/"/> <location xmlns="http://purl.org/net/mlo/" rdf:resource="http://sws.geonames.org/2638360/"/> <rdf:type rdf:resource="http://purl.org/vocab/aiiso/schema#Module"/> <assessment xmlns="http://purl.org/net/mlo/" rdf:resource="http://data.open.ac.uk/saou/assessment/end-of-course-assessment"/> <assessment xmlns="http://purl.org/net/mlo/" rdf:resource="http://data.open.ac.uk/saou/assessment/tma"/> <subject xmlns="http://purl.org/dc/terms/" rdf:resource="http://data.open.ac.uk/topic/arts_and_humanities"/> <is-taught-present xmlns="http://courseware.rkbexplorer.com/ontologies/courseware#" rdf:datatype="http://www.w3.org/2001/XMLSchema#boolean">true</is-taught-present> <taught-at xmlns="http://courseware.rkbexplorer.com/ontologies/courseware#" rdf:resource="http://education.data.gov.uk/id/school/133849"/> <code xmlns="http://purl.org/vocab/aiiso/schema#" rdf:datatype="http://www.w3.org/2001/XMLSchema#string">AA100</code>
    10. 10. N3<http://data.open.ac.uk/course/aa100> <http://purl.org/dc/terms/title> "The arts past and present"^^<http://www.w3.org/2001/XMLSchema#string> . <http://data.open.ac.uk/course/aa100> <http://data.open.ac.uk/saou/ontology#OUCourseLevel> "1"^^<http://www.w3.org/2001/XMLSchema#string> . <http://data.open.ac.uk/course/aa100> <http://data.open.ac.uk/saou/ontology#courseLevel> <http://data.open.ac.uk/saou/ontology#undergraduate> . <http://data.open.ac.uk/course/aa100> <http://purl.org/goodrelations/v1#isSimilarTo> <http://data.open.ac.uk/course/a200> . <http://data.open.ac.uk/course/aa100> <http://data.open.ac.uk/saou/ontology#hasBook> <http://data.open.ac.uk/book/9780571195473> . <http://data.open.ac.uk/course/aa100> <http://data.open.ac.uk/saou/ontology#hasBook> <http://data.open.ac.uk/book/9780582817807> . <http://data.open.ac.uk/course/aa100> <http://purl.org/net/mlo/location> <http://sws.geonames.org/3077311/> . <http://data.open.ac.uk/course/aa100> <http://purl.org/net/mlo/location> <http://sws.geonames.org/597427/> . <http://data.open.ac.uk/course/aa100> <http://purl.org/net/mlo/location> <http://sws.geonames.org/2802361/> . <http://data.open.ac.uk/course/aa100> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://purl.org/vocab/aiiso/schema#Module> . <http://data.open.ac.uk/course/aa100> <http://courseware.rkbexplorer.com/ontologies/courseware#has-title> "The arts past and present"^^<http://www.w3.org/2001/XMLSchema#string> . <http://data.open.ac.uk/course/aa100> <http://purl.org/net/mlo/assessment> <http://data.open.ac.uk/saou/assessment/end-of-course- assessment> . <http://data.open.ac.uk/course/aa100> <http://purl.org/net/mlo/assessment> <http://data.open.ac.uk/saou/assessment/tma> . <http://data.open.ac.uk/course/aa100> <http://purl.org/dc/terms/subject> <http://data.open.ac.uk/topic/classical_studies> . <http://data.open.ac.uk/course/aa100> <http://purl.org/dc/terms/subject> <http://data.open.ac.uk/topic/arts_and_humanities> . <http://data.open.ac.uk/course/aa100> <http://purl.org/dc/terms/subject> <http://data.open.ac.uk/topic/english_language> .
    11. 11. SPARQL • ASK query: is this true? ask {<http://data.open.ac.uk/course/aa100> a aiiso:Module} (is it a module?) ask{<http://data.open.ac.uk/course/aa100> dc:subject ?x} (is there a subject to this module?) • Select query: Get me some data select ?book ?title where { ?x a aiiso:Module. ?x dc:subject <http://data.open.ac.uk/topic/Music>. ?x courseware:setBook ?book. ?book dc:title ?title filter( ?x != <http://data.open.ac.uk/course/aa100> ) } order by ?title limit 100 (get the books associated with courses in music which are not AA100) • Construct query: Build a (sub) RDF graph construct {?agent1 foaf:knows ?agent2} where s {?x bibo:creator ?agent1. ?x bibo:creator ?agent2} (Construct of graph of people knowing each-other because of being co-authors of at least one thing)
    12. 12. SPARQL is also a protocol for Web-based data endpoints…
    13. 13. Example select distinct ?course where { ?course <http://data.open.ac.uk/saou/ontology#isAvailableIn> <http://sws.geonames.org/2328926/>. ?course a <http://purl.org/vocab/aiiso/schema#Module> } Open University courses available in Nigeria (http://sws.geonames.org/2328926/)on http://data.open.ac.uk/query
    14. 14. Example select distinct ?q (count(distinct ?t) as ?n) where { ?q a <http://purl.org/net/mlo/qualification>. ?q <http://data.open.ac.uk/saou/ontology#hasPathway> ?p. ?p <http://data.open.ac.uk/saou/ontology#hasStage> ?s. {{?s <http://data.open.ac.uk/saou/ontology#includesCompulsoryCourse> ?c} union {?s <http://data.open.ac.uk/saou/ontology#includesOptionalCourse> ?c}}. ?c <http://purl.org/dc/terms/subject> ?t. [] <http://www.w3.org/2004/02/skos/core#hasTopConcept> ?t. } group by ?q order by desc(?n) How many top level subjects are represented in individual Open University qualifications on http://data.open.ac.uk/query
    15. 15. Example select ?broader ?term ?narrower where { graph npgg:subjects { ?subject skos:prefLabel ?term . ?subject skos:broader [ skos:prefLabel ?broader ] . ?_ skos:broader ?subject ; skos:prefLabel ?narrower . } filter(regex(?term, "^Stem cells$", "i")) } order by ?broader ?narrower Broader and narrower terms for "Stem cells“ on http://data.nature.com/query
    16. 16. Example select ?doi ?data where { ?doi a npg:Article ; npg:hasDataCitation [ npg:hasLink [ ?_ ?data ] ; npg:type ?type ] . filter(regex(?type, "pdb")) } limit 25 Data citations to the Protein Database on http://data.nature.com/query
    17. 17. SPARQL update Delete query delete {?x ?p ?y} where { ?x a aiiso:Course. ?x ?p ?y. ?a1 aiiso:responsibleFor ?x. ?a2 aiiso:responsibleFor ?x. filter ( ?a1 != ?a2 ) } Insert query insert {?x a onto:WeirdCourse} where{ ?x a aiiso:Course. ?a1 aiiso:responsibleFor ?x. ?a2 aiiso:responsibleFor ?x. filter ( ?a1 != ?a2 ) }
    18. 18. What we will during the hands-on session • Access URIs to get data in different forms – understand how the HTTP protocol is used to access data • Inspect RDF representations of objects – follow links to others • Write SPARQL query to retrieve specific information • Create new data with SPARQL update – think about how to model the data with RDF
    19. 19.  Hands-on session
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