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Classification schemes, thesauri and other
Knowledge Organization Systems
- a Linked Data perspective
Antoine Isaac
Pelagi...
Classification schemes?
Scope: knowledge organization systems (KOS) such as
classification systems, thesauri, gazetteers, ...
Simple Knowledge Organization System
SKOS is for exchanging KOSs as Linked Data (in RDF)
• Better than semi-structured dat...
A SKOS graph
animals
cats
UF domestic cats
RT wildcats
BT animals
SN used only for domestic cats
domestic cats
USE cats
wi...
Representing semantics
The formal way: OWL Semantic Web ontology language
Used for ontologies that enable machine reasonin...
Do we want to represent every vocabulary
as a formal ontology?
It is possible, but not easy
 KOS are large
 KOS have sof...
Europeana and knowledge organisation systems
 Create a “semantic layer” on top of cultural heritage objects
From: Stefan ...
Using KOS in the Europeana Data Model
Enhanced descriptive metadata
Using KOS Linked Data
<skos:Concept rdf:about="http://www.mimo-db.eu/InstrumentsKeywords/2251">
<skos:prefLabel xml:lang="...
Other types of contextual resources
<gn:Feature rdf:about="http://sws.geonames.org/3176959/">
<gn:name>Florence</gn:name>
...
http://blogs.getty.edu/iris/art-
architecture-thesaurus-now-
available-as-linked-open-data/
Multilingual search
'uurglazen' in Italy
http://europeana.eu/portal/search.html?
query=uurglazen&rows=96&qf=COUNTRY%3Aitaly
Vocabularies currently provided to Europeana
Europeana metadata enrichment
Enrichment types and vocabularies
Enrichment
Type
Target
vocabulary
Source metadata
fields
Number of
enriched
objects
Plac...
Work in progress
Entity-based search and browsing
Annotation
Pundit @ DM2E project http://dm2e.eu
Europeana Channels
Seman...
Not only end-user facing functions
Data must be accessible
(Unified) APIs, Linked Data
Data re-users should be able to pro...
Work needed
Vocabulary management and publication
 Europeana developed its own WWI vocabulary based on a
subset of LCSH
Terms transla...
Vocabulary services
http://data.europeana.eu/concept/loc/sh85148236
Representing finer-grained semantics
 More precise relationships and formal semantics
 For query expansion or data valid...
Representing finer-grained semantics
Depth level, concept associations
XKOS
Pre-coordinated strings
MADS/RDF
Representing finer-grained semantics?
Finer-grained semantics can be useful, but core models
are key
They are what most pe...
The need for alignment / co-reference /
reconciliation
KOS 1:
animals
cats
wildcats
KOS 2:
animal
human
object
A lot of work (being) done
 A long line of work in the KOS community: DESIRE,
CARMEN, Renardus, LIMBER, HILT, MSAC, MACS,...
Semantic mismatches
Irish vocabulary
From: Runar Bergheim
Norwegian
vocabulary
skos:exactMatch
Requires flexible approaches
 AMALGAME/CultuurLink:
http://semanticweb.cs.vu.nl/amalgame/
http://cultuurlink.beeldengelui...
Finding and re-using vocabularies
Well-known or new vocabularies
Wikidata, VIAF, Geonames, Pleiades, DBpedia, LCSH…
Data r...
Vocabulary selection criteria
 Available in technically appropriate way
 Well-maintained
 Documented (including metadat...
Take-home messages
Efforts across the whole ecosystem
Publishers of vocabularies, Providers of object data, Application
de...
Thank you!
Antoine Isaac
antoine.isaac@europeana.eu
Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15
Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15
Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15
Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15
Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15
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Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15

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"Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective".
Presentation at the Pelagios Linked Pasts event, July 20-21, 2015.
http://pelagios-project.blogspot.co.uk/2015/03/linked-pasts.html

Published in: Data & Analytics
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Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective - Linked pasts 15

  1. 1. Classification schemes, thesauri and other Knowledge Organization Systems - a Linked Data perspective Antoine Isaac Pelagios: Linked Pasts London, July 20-21, 2015
  2. 2. Classification schemes? Scope: knowledge organization systems (KOS) such as classification systems, thesauri, gazetteers, subject heading lists… (last-minute addition: also time periods, cf. PeriodO  )
  3. 3. Simple Knowledge Organization System SKOS is for exchanging KOSs as Linked Data (in RDF) • Better than semi-structured data (CSV) • Still relatively simple
  4. 4. A SKOS graph animals cats UF domestic cats RT wildcats BT animals SN used only for domestic cats domestic cats USE cats wildcats
  5. 5. Representing semantics The formal way: OWL Semantic Web ontology language Used for ontologies that enable machine reasoning Mother is a class Parent is the class of entities of type Person that are related to at least one other resource of type Person using the child property …
  6. 6. Do we want to represent every vocabulary as a formal ontology? It is possible, but not easy  KOS are large  KOS have softer “semantics” Parent RelatedTerm Child  KOS have a focus on terminological information Child UsedFor Offspring Softer semantics can be useful for many applications!
  7. 7. Europeana and knowledge organisation systems  Create a “semantic layer” on top of cultural heritage objects From: Stefan Gradmann
  8. 8. Using KOS in the Europeana Data Model
  9. 9. Enhanced descriptive metadata
  10. 10. Using KOS Linked Data <skos:Concept rdf:about="http://www.mimo-db.eu/InstrumentsKeywords/2251"> <skos:prefLabel xml:lang="">Harpsichord</skos:prefLabel> <skos:prefLabel xml:lang="de">Cembalo</skos:prefLabel> <skos:prefLabel xml:lang="sv">Cembalo</skos:prefLabel> <skos:prefLabel xml:lang="fr">Clavecin</skos:prefLabel> <skos:prefLabel xml:lang="it">Clavicembalo</skos:prefLabel> <skos:prefLabel xml:lang="en">Harpsichord</skos:prefLabel> <skos:prefLabel xml:lang="nl">Klavecimbel</skos:prefLabel> <skos:broader> <skos:Concept rdf:about="http://www.mimo-db.eu/InstrumentsKeywords/2239"> <skos:prefLabel>Harpsichords</skos:prefLabel> </skos:Concept> </skos:broader> </skos:Concept>
  11. 11. Other types of contextual resources <gn:Feature rdf:about="http://sws.geonames.org/3176959/"> <gn:name>Florence</gn:name> <gn:alternateName xml:lang="ko"> 피렌체 </gn:alternateName> <gn:alternateName xml:lang="ja"> フィレンツェ </gn:alternateName> <gn:alternateName xml:lang="th">ฟลอเรนซ์</gn:alternateName> <gn:alternateName xml:lang="bo">ཧྥུ་ལོ་རོན་ཟིའུ་ཡ།</gn:alternateName> <gn:alternateName xml:lang="cy">Fflorens</gn:alternateName> <gn:alternateName xml:lang="bs">Firenca</gn:alternateName> <gn:alternateName xml:lang="hbs">Firenca</gn:alternateName> <gn:alternateName xml:lang="hr">Firenca</gn:alternateName> <gn:alternateName xml:lang="sq">Firenca</gn:alternateName> <gn:alternateName xml:lang="pl">Firence</gn:alternateName> <gn:alternateName xml:lang="sl">Firence</gn:alternateName> <gn:alternateName xml:lang="lij">Firense</gn:alternateName> <gn:population>371517</gn:population> <wgs84_pos:lat>43.76667</wgs84_pos:lat> <wgs84_pos:long>11.25</wgs84_pos:long>
  12. 12. http://blogs.getty.edu/iris/art- architecture-thesaurus-now- available-as-linked-open-data/
  13. 13. Multilingual search 'uurglazen' in Italy http://europeana.eu/portal/search.html? query=uurglazen&rows=96&qf=COUNTRY%3Aitaly
  14. 14. Vocabularies currently provided to Europeana
  15. 15. Europeana metadata enrichment
  16. 16. Enrichment types and vocabularies Enrichment Type Target vocabulary Source metadata fields Number of enriched objects Places GeoNames dcterms:spatial, dc:coverage 7M Concepts GEMET, DBpedia, dc:subject, dc:type 9.2M Agents DBpedia dc:creator, dc:contributor 144K Time Semium Time dc:date, dc:coverage, dcterms:temporal, edm:year 10,2M
  17. 17. Work in progress Entity-based search and browsing Annotation Pundit @ DM2E project http://dm2e.eu Europeana Channels Semantic auto-completion
  18. 18. Not only end-user facing functions Data must be accessible (Unified) APIs, Linked Data Data re-users should be able to provide enhanced services to their audience easily, especially in digital humanities Specific collection and application needs cannot rely on a handful of generic vocabularies
  19. 19. Work needed
  20. 20. Vocabulary management and publication  Europeana developed its own WWI vocabulary based on a subset of LCSH Terms translated in 10 languages and linked to id.loc.gov
  21. 21. Vocabulary services http://data.europeana.eu/concept/loc/sh85148236
  22. 22. Representing finer-grained semantics  More precise relationships and formal semantics  For query expansion or data validation  E.g. ISO 25964 and Getty SKOS extensions
  23. 23. Representing finer-grained semantics Depth level, concept associations XKOS Pre-coordinated strings MADS/RDF
  24. 24. Representing finer-grained semantics? Finer-grained semantics can be useful, but core models are key They are what most people will start using
  25. 25. The need for alignment / co-reference / reconciliation KOS 1: animals cats wildcats KOS 2: animal human object
  26. 26. A lot of work (being) done  A long line of work in the KOS community: DESIRE, CARMEN, Renardus, LIMBER, HILT, MSAC, MACS, Crisscross, KoMoHe, FAO…  Continued in Linked data context: Pleiades, Wikidata… MACS: 120K links between Library of Congress Subject Headings (LCSH), RAMEAU, Schlagwortnormdatei (SWD)
  27. 27. Semantic mismatches Irish vocabulary From: Runar Bergheim Norwegian vocabulary skos:exactMatch
  28. 28. Requires flexible approaches  AMALGAME/CultuurLink: http://semanticweb.cs.vu.nl/amalgame/ http://cultuurlink.beeldengeluid.nl/
  29. 29. Finding and re-using vocabularies Well-known or new vocabularies Wikidata, VIAF, Geonames, Pleiades, DBpedia, LCSH… Data repositories and inventories The Data Hub
  30. 30. Vocabulary selection criteria  Available in technically appropriate way  Well-maintained  Documented (including metadata)  Well-connected, e.g. equivalent elements in other vocabularies are indicated  Multilingual  Open • license stacking hampers re-use Quality assessment? Cf. Data on the Web Best Practices http://www.w3.org/TR/2015/WD-dwbp-20150625/#dataVocabularies
  31. 31. Take-home messages Efforts across the whole ecosystem Publishers of vocabularies, Providers of object data, Application developers, Researchers… Requires to get very different steps right Implementing standards for data exchange Design consuming applications Not only technical: encouraging open data!
  32. 32. Thank you! Antoine Isaac antoine.isaac@europeana.eu

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