This document describes VoID (Vocabulary of Interlinked Datasets), which is a metadata vocabulary for describing linked datasets and linksets between datasets. VoID allows datasets to provide information about structural metadata, access points, statistics, and interlinking between other datasets. It has been adopted by many datasets in the Linked Open Data cloud.
Computer 10: Lesson 10 - Online Crimes and Hazards
VoID: Metadata for RDF Datasets
1. Digital Enterprise Research Institute www.deri.ie
VoID – Metadata for
RDF datasets
Richard Cyganiak, Linked Data Research Centre
Stefan.Decker@deri.org
http://www.StefanDecker.org/
Copyright 2010 Digital Enterprise Research Institute. All rights reserved.
3. W3C Interest Group note
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http://www.w3.org/TR/void/
3
4. Digital Enterprise Research Institute www.deri.ie
“What business-related datasets are
in the LOD Cloud?”
“Which datasets deal with politics
and transparency in the EU?”
“We have some DERI data. What
could we link it to?”
5. Read …
Digital Enterprise Research Institute www.deri.ie
http://esw.w3.org/TaskForces/CommunityProjects/LinkingOpenData/DataSets
9. And even if we find a dataset …
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10. Standard questions
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What kind of data is there?
Examples?
Is it up to date?
Who publishes it?
Where is the SPARQL endpoint?
Is there a download?
How big is it?
What’s the license?
11. Datasets
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A dataset is a set of RDF triples that are published,
maintained or aggregated by a single provider
12. Linksets
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An RDF link is an RDF triple whose subject and object
are described in different datasets
A linksetis a collection of such RDF links between two
datasets
14. General dataset metadata
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Leveraging DublinCore:
Dataset homepage
Publisher
Title and description
Categorisation
Licensing
Technical features
16. Access metadata
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How to access the actual RDF triples:
SPARQL endpoints
RDF data dumps
Root resources
URI lookup endpoints
OpenSearch description documents
18. Structural metadata
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High-level information about schema and internal
structure of a dataset
Can be helpful when exploring or querying datasets
Example resources
Patterns for resource URIs
Vocabularies
Dataset partitions
Statistics
24. Digital Enterprise Research Institute www.deri.ie
Publishing aVoIDfile alongside a dataset
Turtle
RDFa
Discovery (well-known URI)
http://yoursite/.well-known/void
25. Users
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Used by DBpedia, OpenLink, data.gov.uk, …
30% of LOD datasets have VoID metadata
The entire LOD Cloud described inVoID:
semantic.ckan.net
27. Ed Summers’ LOD Graph
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28. Summary
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Metadata for linked datasets
For the 4-5 star datasets
W3C Interest Group note (VoID 2)
http://www.w3.org/TR/void/
Leverages Dublin Core, FOAF, etc.
Used by DBpedia, OpenLink, data.gov.uk, …
Used to generate the LOD Cloud diagram
The entire LOD Cloud described in VoID:
semantic.ckan.net
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