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

1. Linked Data Introduction
@sssw2013 - #sssw2013

2. Data

3. Linked Data

4. The Semantic Web

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. Basis
• URIs and Web based information access
• RDF, graph-based data modelling
• SPARQL, querying and updating over web
endpoints

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. 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. 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. 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. 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. SPARQL is also a protocol for Web-based data
endpoints…

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. 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. 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. 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. 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. 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.  Hands-on session