Linked Data and SKOS
2011 Workshop on Physics Classification, Boston
November 28th, 2011
Bernhard Haslhofer | Cornell University, Information Science

Linked Data
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Web Architecture
HTML HTML HTML
hyperlinks hyperlinks
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

But sometimes we need programmatic
access the underlying content, metadata, and
vocabularies.
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Web APIs
API API API API API
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Web APIs - Drawbacks
• Each Web API has a proprietary interface
• Datasources must be known in advance
• Information entities (papers, authors,
subjects, etc.) are not linked
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Linked Open Data Vision
• Publish and link structured data on the Web
• Create a single global data space based on
the Architecture of the World Wide Web
RDF RDF RDF
RDF links RDF links
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Linked Data Example
http://xmlns.com/foaf/
spec/#term_Person
N. M. R. Peres
...
rdf:type
http://purl.org/ontology/
bibo/Article foaf:name
http://arxiv.org/authors/ http://aps.org/authors/
owl:sameAs
Peres_N peres_nmr
rdf:type
dcterms:creator dcterms:creator
http://arxiv.org/resource/ http://prb.aps.org/resource/
owl:sameAs
cond-mat/0512091 PRB/v73/i12/e125411
dc:title
...
Electronic Properties of Disordered
Two-Dimensional Carbon
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Publishing Linked Data
• Distinguish between non-information (NIR) and
information resource (IR)
• Sample NIR
• http://arxiv.org/resource/cond-mat/0512091
• Sample IRs
• http://arxiv.org/abs/cond-mat/0512091 (HTML)
• http://arxiv.org/data/cond-mat/0512091 (RDF)
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

The Simple Knowledge
Organization System (SKOS)
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

What is SKOS?
• A language for describing controlled
vocabularies (taxonomies, classification
schemes, thesauri)
• Builds on Linked Data principles
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

SKOS Examples
skos:Concept
rdf:type
arxiv:cond-mat
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix arxiv: <http://arxiv.org/subjects/> .
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

SKOS Examples
"Condensed Matter
Physics"@en
skos:prefLabel
skos:Concept "Kondensierte Materie
skos:prefLabel
arxiv:cond-mat Physik"@de
skos:altLabel
"Physics"@en
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

SKOS Examples
skos:broader
skos:Concept "Condensed Matter
skos:prefLabel
arxiv:cond-mat Physics"@en
skos:narrower skos:broader
skos:Concept "Physics - Statistical
skos:prefLabel
arxiv:cond-mat.stat-mech Mechanics"@en
skos:narrower
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

SKOS Example
skos:broader
skos:Concept
...
skos:Concept
skos:related
arxiv:cond-mat
skos:narrower
skos:closeMatch
dbpedia:
Condensed_matter_
physics
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

SKOS Examples
ex1:someConceptScheme ex2:otherConceptScheme
skos:Concept skos:Concept
arxiv:cond-mat aps:....
skos:exactMatch
skos:Concept skos:broadMatch skos:Concept
arxiv:physics.data-
aps:....
an
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011

Summary
• Linked Data is about exposing and linking
structured data on the Web
• SKOS is a language for expressing
controlled vocabularies
• SKOS vocabularies can be published as
Linked Data
2011 Workshop on Physics Classification | Boston, MA | Nov. 28th, 2011