linked data: a short(-ish) introduction
DESCRIPTION
A short introduction to Linked Data, for project meeting of Bricolage project, ILRT, Bristol, Thursday 26 Jan 2012TRANSCRIPT
Linked DataA short(-ish) introductionBricolage Project meeting, Bristol, 26 Jan 2012
Pete Johnston Technical Researcher, [email protected]
Document Web Principles
• Use URIs as names of documents• Use http URIs, so that people can use HTTP protocol to
look up those names• When someone looks up a URI, provide the document
(*)• Use document standards, e.g. HTML• Include links to other documents, so that people can
discover more documents
Use URIs as names of documents
http://en.wikipedia.org/wiki/D.H._Lawrence
Use http URIs…
http://en.wikipedia.org/wiki/D.H._Lawrence
Provide the documents
Use document standards
Include links to other docs
• Links typically “untyped”<a href="/wiki/Eastwood,_Nottinghamshire" title="Eastwood,
Nottinghamshire">Eastwood</a>
<a href="/wiki/Lady_Chatterley%27s_Lover" title="Lady Chatterley's Lover">Lady Chatterley's Lover</a>
<a href="/wiki/Joseph_Conrad" title="Joseph Conrad">Joseph Conrad</a>
Occasionally “typed”<link rel="copyright“ href=“http://creativecommons.org/licenses/by-sa/3.0/" />
(*) On “providing the document”: content negotiation
• Client HTTP request for doc includes info about preferences, e.g.• Language (Prefer English, but will accept Spanish)• Media-type (Prefer XHTML, but will accept HTML,
plain text)• Server responds with representation of doc which best
matches preferences
Linked Data Principles (a version!)
• Use URIs as names of things• people, places, concepts, documents… anything!• (avoid URI ambiguity)
• Use http URIs so that people and programs can look up those names
• When a person or program looks up a name, provide (representations of) documents about the things
Linked Data Principles (a version!)
Use data standards: RDF Include typed links to other things
so that people and programs can discover other things
Use URIs as names of things
http://dbpedia.org/resource/D.H._Lawrence
Use http URIs…
http://dbpedia.org/resource/D.H._Lawrence
Provide documents about those things…
Thing:http://dbpedia.org/resource/D.H._Lawrence
Document:http://dbpedia.org/page/D.H._Lawrence
…with representations suitable for people…
…and representations suitable for programs
Use data standards: RDF
• A way to model data• Assertions of relationships between two things• Triples: subject, predicate, object
DH Lawrence has-notable-work Lady Chatterley's Lover
Use data standards: RDF
• Triples: use URIs as “words”/names <http://dbpedia.org/resource/D._H._Lawrence> <http://dbpedia.org/ontology/notableWork> <http://dbpedia.org/resource/Lady_Chatterley
%27s_Lover>• In RDF syntaxes, URIs often abbreviated
• dbpedia:D._H._Lawrence
Use data standards: RDF
• Extensibility of vocabulary• Reuse of vocabulary• “Self-description”
• vocabulary terms described using RDF• Rules for data merging/integration• “Formal semantics”, basis for inferencing
Include typed links to other things
dbpedia:D._H._Lawrence dbp-owl:birthPlace dbpedia:Eastwood,_Nottinghamshire ; dbp-owl:notableWork dbpedia:Lady_Chatterley%27s_Lover ; dbp-owl:influencedBy dbpedia:Joseph_Conrad .
“Linked data is data you can click on”(?John Sheridan, National Archives)
Linked Data from British Library: D. H. Lawrence
Linked Data from OCLC VIAF: D. H. Lawrence
Linked Data from Freebase: D. H. Lawrence
Linked Data from BBC: Programmes related to D. H. Lawrence
Archives Hub EAD data: D. H. Lawrence letters
Sindice/Sig.ma: RDF data aggregator/search
RDF & Linked Data: some strengths/features
• Designed for the Web, “open world”• Anyone can say anything about anything• No-one says everything about anything
• Extensible, decentralised• Rules for data merging/integration• Inferencing
RDF & Linked Data: Some challenges
New concepts, formats, tools (Re)modelling/migration/conversion Linking & identity Versioning & time Trust
How?
• Model our “world” • Design URI patterns• Select/create RDF vocabularies• Convert/transform data• Generate links• Publish/expose data
Acknowledgements / some useful sources
• Tom Heath & Chris Bizer, Linked Data: Evolving the Web into a Global Data Space http://linkeddatabook.com/
• Yves Raimond & Michael Smethurst, “A skim-read introduction to linked data”http://www.bbc.co.uk/blogs/radiolabs/s5/linked-data/s5.html
• Dave Reynolds, “Linked data and its role in the semantic web”http://www.slideshare.net/der42/introduction-to-linked-data-and-the-semantic-web-8700415
Linked DataA short(-ish) introductionBricolage Project meeting, Bristol, 26 Jan 2012
Pete Johnston Technical Researcher, [email protected]