The document discusses opportunities and challenges in linked (open) data, outlining its historical development and core specifications, including the principles of the semantic web. It compares linked data with traditional library practices, highlighting the strengths and risks associated with both domains. The conclusion emphasizes the potential for libraries to leverage linked data technologies to enhance their services and improve interoperability in the digital space.

1. Linked (Open) Data
Opportunities and challenges
Makx Dekkers
mail@makxdekkers.com

2. Outline
• Basic notions
• Recent developments
• Comparing objectives
• Opportunities and risks
• Conclusions
© 2011 Makx Dekkers Journeés ABES 2011 2

3. BASIC NOTIONS
© 2011 Makx Dekkers Journeés ABES 2011 3

4. The idea and its history
• 1989: Tim Berners-Lee already talked about
linking documents and data together
(http://www.w3.org/History/1989/proposal.html)
• 2001: Tim Berners-Lee and Ora Lassila
introduced the “Semantic Web”
(http://www.scientificamerican.com/article.cfm?id=the-semantic-web)
• 2006: Tim Berners-Lee presented the initial
design issues (rules) for Linked Data
(http://www.w3.org/DesignIssues/LinkedData.html)
© 2011 Makx Dekkers Journeés ABES 2011 4

5. W3C Semantic Web initiative
• Objective
– to create a universal medium for the exchange of
data […] to smoothly interconnect personal
information management, enterprise application
integration, and the global sharing of commercial,
scientific and cultural data
• Main results
– Resource Description Framework (RDF), RDFa
(RDF-in-HTML), SPARQL Query Language
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6. Core Linked Data Specifications
• Transport
– HTTP Hypertext Transfer Protocol
• Identification
– URI Uniform Resource Identifier
• Description and linking
– RDF Resource Description Framework
• Search and access
– SPARQL Query Language for RDF
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7. The four rules of Linked Data
• TBL’s recommendations:
1. Use URIs as names for things
2. Use HTTP URIs so that people can look up those
names
3. When someone looks up a URI, provide useful
information, using the standards (RDF*, SPARQL)
4. Include links to other URIs so that they can
discover more things
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8. The basic model of RDF
• Resource Description Framework “triple”:
– Subject: the “thing” (resource) described
– Predicate: the characteristic of the resource
– Object: the value of the characteristic
Subject Object
Predicate
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9. Complex structures in RDF
This
presentation
Makx
Dekkers Barcelona
Journées ABES
ABES
Montpellier
17-18 May 2011
presenter
partOf organizer location
hometown
date
location
© 2011 Makx Dekkers Journeés ABES 2011 9

10. Linked (Open / Enterprise) Data
• Commonalities
– Using Semantic Web technologies (RDF)
– Linking information resources, people, places
• Differences
– Open Data with open licenses; Enterprise Data
mostly for closed, controlled environments
– Open Data links to other Open Data, available for
external use; Enterprise Data may link to external
data but not openly available for external use
© 2011 Makx Dekkers Journeés ABES 2011 10

11. Linked Data -- Open Data
• Linked Data: focus on technology
– Semantic Web: Resource Description Framework,
and other Web standards
– Final solutions still under development
• Open Data: focus on strategy
– Based on notion that sharing is important and
benefits all
– Technology is secondary
© 2011 Makx Dekkers Journeés ABES 2011 11

12. The five-star system
Source: http://inkdroid.org/journal/2010/06/04/the-5-stars-of-open-linked-data/
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13. The LOD diagram: 2007
Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/
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25 datasets

14. The LOD diagram: 2008
Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/
© 2011 Makx Dekkers Journeés ABES 2011 14
45 datasets

15. The LOD diagram: 2009
Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/
© 2011 Makx Dekkers Journeés ABES 2011 15
95 datasets

16. The LOD diagram: 2010
Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/
© 2011 Makx Dekkers Journeés ABES 2011 16
203 datasets

17. RECENT DEVELOPMENTS
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18. W3C communities
• LinkingOpenData SWEO Community Project
– Goal: to extend the Web with a data commons by
publishing various open data sets as RDF on the
Web and by setting RDF links between data items
from different data sources
(http://www.w3.org/wiki/SweoIG/TaskForces/CommunityProjects/LinkingOpenData)
• Library Linked Data Incubator Group
– to help increase global interoperability of library
data on the Web (http://www.w3.org/2005/Incubator/lld/)
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19. More W3C communities
• Government Linking Data Working Group
– to provide standards and other information which
help governments around the world publish their
data as effective and usable linked data
(http://www.w3.org/2011/gld/charter)
• Semantic Web Health Care and Life Sciences
(HCLS) Interest Group
– to develop, advocate for, and support the use of
Semantic Web technologies for health care and
life science (e.g. biology, medicine)
(http://www.w3.org/2001/sw/hcls/)
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20. Open Knowledge Foundation, okfn.org
• not-for-profit organization promoting open
knowledge: any kind of data and content that
can be freely used, reused, and redistributed
• Working and Interest Groups, e.g.
– Open Data in Science, Open Government Data,
Open Bibliographic Data, Cultural Heritage etc.
• CKAN.net: registry of open datasets and other
“knowledge resources”
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21. Linked Data initiatives
Predicate vocabularies (descriptors)
Research Description and Access (RDA) http://metadataregistry.org/rdabrowse.htm
The Bibliographic Ontology (BIBO) http://bibliontology.com/
Dublin Core http://dublincore.org/
Object vocabularies (values)
Virtual International Authority File (VIAF) http://viaf.org/
Library of Congress authorities http://id.loc.gov/authorities/
AgroVOC (agricultural terminology) e.g. http://aims.fao.org/aos/agrovoc/c_550
DBPedia (based on Wikipedia) e.g. http://dbpedia.org/page/Montpellier
Bibliographic data
LIBRIS Sweden e.g. http://libris.kb.se/library/S
British Library http://www.bl.uk/bibliographic/datasamples.html
CrossRef (DOI metadata) http://www.crossref.org/CrossTech/linked_data/
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22. More Linked Data initiatives
Broadcasting, publishing
BBC http://www.bbc.co.uk/blogs/bbcinternet/linked_data/
New York Times http://data.nytimes.com/
Governments (small sample)
USA http://data.gov/
France http://opendata.paris.fr/
Finland http://data.suomi.fi/
UK http://data.gov.uk/
Spain (Cataluña) http://dadesobertes.gencat.cat/
Norway http://data.norge.no
Netherlands http://www.overheid.nl/opendata
Australia http://data.gov.au/
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23. COMPARING OBJECTIVES
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24. Strategic aspects Linked Data
• Achieving global interoperability with minimal
coordination
• Aggregating human knowledge
• Supporting democracy, transparency and
accountability
• Enhancing and enriching information
• Enabling user-driven and user-generated
applications
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25. Strategic aspects libraries
• Organizing information for use by specific
users for specific goals
• Ensuring and maintaining quality
• Sustaining services economically
• Preserving information for the long term
• Providing trusted services
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26. Functional aspects Linked Data
• Searching distributed collections
• “Following your nose” – navigating links
between pieces of content
• Distributing responsibility for making
statements about things
• Leaving to the user whom and what to trust
• Leaving development of products and services
to an open market (apps)
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27. Functional aspects libraries
• Describing information by professionals
• Bringing together and managing aggregations
of information
• Selecting relevant information
• Mixing analogue and digital resources
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28. Technical aspects Linked Data
• Publishing and using machine-readable
statements (“data that speak for themselves”)
• Focusing on Semantic Web technology
• Enabling inferences across large distributed
data sets
• (Still to be done) Solving issues around
harvesting, caching and real-time updating
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29. Technical aspects libraries
• Using proven technology to provide high-
quality services
• Managing production systems and services
• Guaranteeing performance, uptime,
consistency across data
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30. Agility versus sustainability
• In the Linked Data space:
– Things move fast
– Trial-and-error
– Lots of development by volunteers (hackers)
• In the library domain:
– Operational systems need to evolve
– Need to handle legacy data
– Development by professionals in managed
projects
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31. Data versus services
• In the Linked Data space:
– Focus on availability of “raw data”
– Quality is secondary
– Data and technology should lead to useful results
• In the library domain:
– Focus on services
– Quality is essential
– Data and technology in support of the service
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32. Economic aspects
• In the Linked Data space:
– “Information wants to be free” – a human right?
– Short-term thinking: today is hot, yesterday is not
– Focus on applications to create value out of data
• In the library domain:
– Long-term view: sustainability is crucial
– Public money to provide community services
– Expected to do more with less money
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33. OPPORTUNITIES AND RISKS
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34. Strong points Linked Data
• Attempt to create a common technical
platform for machine-readable data
• Lots of enthusiasm in publishing open data
• Promise of global interoperability
• Mix of researchers, user communities,
hackers, professional data providers
• High visibility on political level
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35. Risks Linked Data
• Driven by technology, not by requirements
• Technology may not (yet) be stable – RDF 2.0?
• Operational issues far from solved (reliability,
performance, quality, security, trust)
• Hope for general agreement across domains
may not be realistic
• Promise may turn into disappointment
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36. Strong points libraries
• Long time operational experience in managing
information
• Professional intermediaries between users
and information needs
• Sustainable business models (albeit with
eternally shrinking budgets)
• Long-term perspective: the past (legacy data)
as well as the future (preservation)
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37. Risks libraries
• Technologies change rapidly
• New skills difficult to spread through the
organization
• Some people see libraries as a thing of the
past (“the book museum”)
• Underestimation of information handling skills
• Information overload, human intervention
does not scale, need for better tools
© 2011 Makx Dekkers Journeés ABES 2011 37

38. Meeting both worlds
• An example: Europeana.eu
– Started out with domain perspectives (libraries,
archives, museums, audiovisual archives)
– “Traditional” approach (metadata mappings)
works but insufficient
– Using Linked Data approach preserves domain
specifics but allows for generalization to support
common services
– Cross-domain (but co-ordinated) interoperability
© 2011 Makx Dekkers Journeés ABES 2011 38

39. Europeana Data Model
Classes Properties
Simple example
Complex
example
Source at:
http://version1.europeana.eu/web/europeana-project/technicaldocuments/
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40. CONCLUSION
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41. Libraries and Linked Data
• Using Linked Data technology as the next step
in connecting services
• Offering information management skills to the
technology domain
• Creating a quality hub in the Linked Data
space
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42. Best of both worlds
• Libraries providing stability and sustainability
to Linked Data spaces
• Library professionals helping to manage the
distributed collections
• Libraries delivering high-quality linked data to
the Web
• Technologists to provide the next generation
of systems and tools
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43. Linked (Open) Data:
opportunity for libraries!
Thank you!
Makx Dekkers
mail@makxdekkers.com