This document discusses opportunities and challenges of Linked Data. It begins with an overview of Linked Data principles like using URIs to identify things and linking related things. It then discusses enabling technologies like HTTP URIs and SPARQL queries. Opportunities mentioned include using the LOD cloud as a test bed and benefiting from linked context in applications. Challenges include large-scale processing of Linked Data and quality of links. The document concludes by emphasizing the potential of Linked Data to make data more valuable.

1. 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

2. Linked Data 101

3. 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

4. HTTP URIs

5. 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>

6. 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" .

7. 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>

8. 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> .

9. Linked Open Data

10. Linked Open Data cloud
2007 2008
2008 2010
2009
2008 2009
2008
10

11. Linked Open Data cloud
http://lod-cloud.net/
Over 300 open data sets with 40 billion facts, interlinked by 500 million typed links.

12. Linked Open Data cloud stats
Digital Enterprise Research Institute www.deri.ie
triples distribution
links distribution
http://lod-cloud.net/state/
Enabling Networked Knowledge

13. … cost and benefits

14. Linked Data life cycles

15. Linked Data life cycles
Digital Enterprise Research Institute www.deri.ie
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
Enabling Networked Knowledge

16. Modeling
Digital Enterprise Research Institute www.deri.ie
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
Enabling Networked Knowledge

17. Neologism
Digital Enterprise Research Institute www.deri.ie
http://neologism.deri.ie/
Enabling Networked Knowledge

18. Neologism
Digital Enterprise Research Institute www.deri.ie
http://vocab.data.gov/
Enabling Networked Knowledge

19. Schema.org – Linked Data
Digital Enterprise Research Institute www.deri.ie
Enabling Networked Knowledge

20. Publishing
Digital Enterprise Research Institute www.deri.ie
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
Enabling Networked Knowledge

21. Google Refine extension
Digital Enterprise Research Institute www.deri.ie
http://lab.linkeddata.deri.ie/2010/grefine-rdf-extension/
Enabling Networked Knowledge

22. RDB2RDF – D2RQ
Digital Enterprise Research Institute www.deri.ie
http://d2rq.org/
Enabling Networked Knowledge

23. Discovery
Digital Enterprise Research Institute www.deri.ie
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
Enabling Networked Knowledge

24. Follow-Your-Nose
Digital Enterprise Research Institute www.deri.ie
Enabling Networked Knowledge
24

25. Dataset discovery
Digital Enterprise Research Institute www.deri.ie
http://dsi.lod-cloud.net/
Enabling Networked Knowledge

26. Integration
Digital Enterprise Research Institute www.deri.ie
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
Enabling Networked Knowledge

27. Why linking?
Digital Enterprise Research Institute www.deri.ie
http://webofdata.wordpress.com/2011/05/22/why-we-link/
Central Contractor Registration (CCR)
Geonames
Enabling Networked Knowledge

28. Effort distribution
Digital Enterprise Research Institute www.deri.ie
Third
Fix Publisher‘s Party
Effort
Overall Data Effort
Integration
Effort
Consumer‘s
Effort
Enabling Networked Knowledge

29. LATC – Interlinking Platform
Digital Enterprise Research Institute www.deri.ie
http://latc-project.eu/platform
Enabling Networked Knowledge

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

31. Conclusion
Digital Enterprise Research Institute www.deri.ie
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
Enabling Networked Knowledge

32. Resources
Digital Enterprise Research Institute www.deri.ie
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)
Enabling Networked Knowledge