Linked Data: opportunities and challenges

Digital Enterprise Research Institute www.deri.ie

Linked Data:
opportunities and challenges
Dr. Michael Hausenblas, DERI, NUI Galway

Open Science Data Cloud NSF PIRE Workshop, Edinburgh, UK, 18 July 2012

Copyright 2011 Digital Enterprise Research Institute. All rights reserved.

Enabling Networked Knowledge

Linked Data principles

① Use URIs to identify the “things” in your data

② Use HTTP URIs so people & machines can look them up

③ When a URI is looked up return a description of the thing in a
structured format (RDF)

④ Link to related things to provide context

http://www.w3.org/DesignIssues/LinkedData.html

HTTP URIs

curl -L -H "Accept: application/rdf+xml" http://dbpedia.org/resource/Edinburgh

<?xml version="1.0" encoding="utf-8" ?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:owl="http://www.w3.org/2002/07/owl#"
xmlns:foaf="http://xmlns.com/foaf/0.1/"
xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#"
xmlns:dbpedia-owl="http://dbpedia.org/ontology/"
xmlns:dcterms="http://purl.org/dc/terms/"
xmlns:dbpprop="http://dbpedia.org/property/"
xmlns:ns10="http://dbpedia.org/property/start/" >
<rdf:Description rdf:about="http://dbpedia.org/resource/Firrhill_High_School">
<dbpedia-owl:city rdf:resource="http://dbpedia.org/resource/Edinburgh" />
</rdf:Description>
<rdf:Description rdf:about="http://dbpedia.org/resource/Murrayfield_Stadium">
<dbpedia-owl:location rdf:resource="http://dbpedia.org/resource/Edinburgh" />
<dbpprop:location rdf:resource="http://dbpedia.org/resource/Edinburgh" />
</rdf:Description>
<rdf:Description rdf:about="http://dbpedia.org/resource/Stewart%27s_Melville_College">
<dbpedia-owl:city rdf:resource="http://dbpedia.org/resource/Edinburgh" />
<dbpprop:city rdf:resource="http://dbpedia.org/resource/Edinburgh" />
</rdf:Description>

HTTP URIs

curl -L -H "Accept: text/turtle" http://data.ordnancesurvey.co.uk/id/7000000000017765

<http://data.ordnancesurvey.co.uk/doc/7000000000017765> rdf:type foaf:Document, dctype:Text ;
foaf:primaryTopic <http://data.ordnancesurvey.co.uk/id/7000000000017765> ;
dct:title "Linked Data for The County of Hampshire" ;
dct:hasFormat <http://data.ordnancesurvey.co.uk/doc/7000000000017765.rdf> ,
<http://data.ordnancesurvey.co.uk/doc/7000000000017765.html> ,
<http://data.ordnancesurvey.co.uk/doc/7000000000017765.json> ,
<http://data.ordnancesurvey.co.uk/doc/7000000000017765.ttl> .

<http://data.ordnancesurvey.co.uk/id/7000000000017636> rdfs:label "Tadley" ;
skos:prefLabel "Tadley" .

<http://data.ordnancesurvey.co.uk/id/7000000000017510> rdfs:label "Newton Valence" ;
skos:prefLabel "Newton Valence" .

<http://data.ordnancesurvey.co.uk/id/7000000000017817> rdfs:label "Ashmansworth" ;
skos:prefLabel "Ashmansworth" .

HTTP URIs

curl -L -H "Accept: text/turtle” http://bio2rdf.org/genbank:AC008393

@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix dc: http://purl.org/dc/elements/1.1/ .

<http://bio2rdf.org/genbank:AC008393> a <http://bio2rdf.org/genbank_resource:Sequence> ;
rdfs:label "Homo sapiens chromosome 5 clone CTC-241N9, complete sequence [genbank:AC008393]"
;
owl:sameAs <http://bio2rdf.org/genbank:ac008393> ;
dc:title "Homo sapiens chromosome 5 clone CTC-241N9, complete sequence" ;
dc:modified "26-FEB-2002" ;
<http://bio2rdf.org/bio2rdf_resource:length> "166847" ;
<http://bio2rdf.org/bio2rdf_resource:linkedToFrom>

HTTP URIs

curl -L -H "Accept: text/turtle” http://bnb.data.bl.uk/doc/resource/009468944

@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix dct: <http://purl.org/dc/terms/> .
@prefix blterms: <http://www.bl.uk/schemas/bibliographic/blterms#> .
@prefix elements: <http://iflastandards.info/ns/isbd/elements/> .
@prefix bibo: <http://purl.org/ontology/bibo/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix linked-data: <http://purl.org/linked-data/api/vocab#> .
@prefix void: <http://rdfs.org/ns/void#> .

<http://bnb.data.bl.uk/id/resource/009468944> dct:language <http://lexvo.org/id/iso639-3/eng> ;
rdfs:seeAlso <http://www4.wiwiss.fu-berlin.de/bookmashup/books/0859761541> ;
elements:P1053 "vii,147p."@en ;
rdfs:label "William Wallace / Andrew Fisher" ;
blterms:bnb "GB8714157" ;
dct:creator <http://bnb.data.bl.uk/id/person/FisherAndrew1935-> ;
bibo:isbn10 "0859761541" ;
dct:title "William Wallace" ;
rdf:type bibo:Book ,
dct:BibliographicResource ;
dct:subject <http://bnb.data.bl.uk/id/concept/ddc/e19/941.1020924> .

Linked Open Data cloud

2007 2008
2008 2010
2009
2008 2009
2008

10

Linked Open Data cloud
http://lod-cloud.net/

Over 300 open data sets with 40 billion facts, interlinked by 500 million typed links.

Linked Open Data cloud stats

triples distribution

links distribution

http://lod-cloud.net/state/


Linked Data life cycles

http://linked-data-life-cycles.info

1 2 3 4 5 6

data modeling publishing discovery integration use cases
awareness

LOD cloud Neologism Google Refine FYN LATC 24/7 data-gov.ie

5stardata.info Schema.org D2RQ LATC DSI


Modeling

1 2 3 4 5 6

awareness




Neologism

http://neologism.deri.ie/


Neologism

http://vocab.data.gov/


Schema.org – Linked Data


Publishing

1 2 3 4 5 6

awareness




Google Refine extension

http://lab.linkeddata.deri.ie/2010/grefine-rdf-extension/


RDB2RDF – D2RQ

http://d2rq.org/


Discovery

1 2 3 4 5 6

awareness




Follow-Your-Nose

24

Dataset discovery

http://dsi.lod-cloud.net/


Integration

1 2 3 4 5 6

awareness




Why linking?

http://webofdata.wordpress.com/2011/05/22/why-we-link/

Central Contractor Registration (CCR)

Geonames


Effort distribution

Third
Fix Publisher‘s Party
Effort
Overall Data Effort
Integration
Effort
Consumer‘s
Effort


LATC – Interlinking Platform

http://latc-project.eu/platform


http://www4.wiwiss.fu-berlin.de/latc/toollibrary/screencast.html

Conclusion
Opportunities
 Use the LOD cloud as test-bed (experiments)
 Benefit from LOD cloud in apps (context)
 Contribute to make your data more valuable

Challenges
 Large-scale processing of Linked Data
 Distributed/federated SPARQL queries
 Quality of links and the data


Resources

Tutorials, technologies, specifications:
 http://linkeddatabook.com
 http://lod-cloud.net
 http://linkeddata.org
 http://linkeddata-specs.info
 http://schema.rdfs.org

Videos:
 http://ted.com/talks/tim_berners_lee_on_the_next_web.html - Tim Berners-Lee’s TED talk
 http://www.youtube.com/watch?v=GKfJ5onP5SQ - Linked Data (and the Web of Data)
 http://www.youtube.com/watch?v=4x_xzT5eF5Q - What is Linked Data?
 http://vimeo.com/36752317 - Linked Open Data (by Europeana)


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Editor's Notes