On Libraries & Linked Data

Antoine Isaac

UB Utrecht, April 6, 2011

Who am I?

• Europeana• Web & Media Lab, Vrije Universiteit Amsterdam

• W3C Library Linked Data group• (2006-2009) W3C Semantic Web Deployment group

SKOS

aisaac@few.vu.nl

DemoFollowing one’s nose to subject heading lists as linked data• American LCSH

http://id.loc.gov/authorities/sh85145447#concept

• French RAMEAUhttp://stitch.cs.vu.nl/vocabularies/rameau/ark:/12148/cb11931913j

• German SWDhttp://d-nb.info/gnd/4064689-0

• Agrovochttp://aims.fao.org/aos/agrovoc/c_8309

• STWhttp://zbw.eu/stw/descriptor/14188-0

• Further on to DBPediahttp://dbpedia.org/resource/Water

Demo (fallback option)

Subject heading lists as SKOS linked data• American LCSH http://id.loc.gov• French RAMEAU: http://stitch.cs.vu.nl/rameau• German SWD: http://d-nb.info/gnd/ • mapped using manual links from the MACS project

http://macs.cenl.org

Starting from http://id.loc.gov/authorities/sh85014310#concept

Linked Data?

1. Use URIs as names for things2. Use HTTP URIs so that people can look up those names3. When someone looks up a URI, provide useful information

using standards (RDF, SPARQL)4. Include links to other URIs, so that they can discover more

things

Tim Berners-Lee, http://linkeddata.org/

(Linked) Data Representation

• That subject heading data follows a link-intensive data modelUniform resource identifiers (URI)Resource Description Framework (RDF)

(Linked) Data Representation

• Use more-or-less the same standard vocabularySimple Knowledge Organization System (SKOS)http://www.w3.org/2004/02/skos/ For representing thesauri, classifications, etc. on the

Semantic Web

A SKOS graphanimalscats

UF domestic catsRT wildcatsBT animalsSN used only for domestic

catsdomestic cats

USE catswildcats

SKOS mappings

SKOS provides conceptual links to bridge across different contexts

KOS 1:animalscatswildcats

KOS 2:animalhumanobject

Links in the data

Links in the data

Growing interest for linked data in the library community

Linked Library Cloud beginning 2008

[Ross Singer, Code4Lib2010]

http://code4lib.org/conference/2010/singer

Linked Library “sector” in 2010

Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/

Libraries and LD, the perfect match?

• Libraries have been producing (meta)data for ages• Libraries (often) produce high-quality metadata

Libraries and LD, the perfect match?

• Library metadata was locked in record silos• But it maintain links to the outside world

• Bibliographic and web references• Shared vocabularies• Same books!

Libraries and LD, the perfect match?

LD is about• Citing object• Linking to them• Re-using data

Think of web-native union catalogues

Johan Stapel, Koninklijke Bibliotheek (now bibliotheek.nl)

A vision for the Dutch National Library

A web of cultural heritage data?

?

?

The current portal

Towards semantic search: facets

Building a search engine on top of metadata is difficultIntrinsic quality problems: correctness, coverage

Especially when data is so heterogeneous100s of formatsFrom flat 5-fields records to 100-nodes XML treesLanguage issue!

We currently use a simple, flat interoperability formatQuick-win quickly showing its limits

We can better use institutions’ original metadata

Accommodate their different practicesData structures and semantics

Access objects via a semantic layer of vocabularies for subjects, persons, places…

Semantic ThoughtLab: experimenting solutions

Towards semantics-enabled searchBuilding a "semantic layer" to help accessing content

Towards semantics-enabled search

• Enhance access to Europeana content by semantics– Query expansion, clustering of results

• Exploiting various types of relations– "located in", "lived in", "is more specific concept"…

• Semantics are already there, in metadata and "controlled vocabularies" used in metadata– Thesauri, classifications…

• Requires to make it properly machine-accessible

Europeana Data Model

Trying to evolve towards RDF and Linked Data• Representing objects, persons, places, etc. as

resources• Linking and re-using external sources• (Re-using) richer data modeling features

SKOS, CIDOC-CRM, OAI-ORE

• Enabling domain-specific data profiles• Separating original data from enrichments

http://version1.europeana.eu/web/europeana-project/technicaldocuments/

Prototype: Europeana Thought Lab

http://europeana.eu/portal/thought-lab.html

Clustering of results

Baseline: matching concepts' label

Controlled place name from a vocabulary at the Rijskmuseum

Metadata for the object

A "more specific Egypte"?

A "more specific Egypte"?Metadata for the object

A place more specific than the Egypt one

Semantic information on the Giza place in the Rijskmuseum Vocabulary

Following other relations

Following other relations - creator

Metadata for the object

Controlled person name from a vocabulary at the Rijskmuseum

Following other relations - matchInformation on Gustave Le Gray from the Rijskmuseum Vocabulary

Matched to a "Gustave Le Gray" from another Vocabulary

Enabling bits & pieces

Exploiting semantic links in CH vocabulariesConcept “Giza” narrower than concept “Egypte”

Mapping/alignment between CH vocabulariesLouvre’s “Égypte” equivalent to Rijksmuseum’s “Egypte”

Enrichment of existing metadataThe string “Egypt” in a metadata record indicates the concept of

Egypt defined in Rijksmuseum thesaurus

Challenge #1: Linking

Challenge #1: Linking

Manual mapping of large vocabularies is labour-intensive• LCSH, RAMEAU and SWD mapped in the MACS project

http://macs.cenl.org • SWD and DDC mapped in the CRISS-CROSS project

http://linux2.fbi.fh-koeln.de/crisscross/

Automatic linking is not perfect but can help• STW, AGROVOC…• Some studies (and further pointers) for automatic library

thesaurus alignment in the STITCH projecthttp://stitch.cs.vu.nl

Challenge #1: Linking

• (Semi-)automatic techniques are necessary to– Connect objects to vocabularies (esp. for legacy data)– Connect objects themselves together

• Crowdsourcing?

• Making the way librarians create metadata evolve?

Linking strategy for libraries?

Linking strategy for libraries?

• Links to library-originated sources– VIAF, LCSH, DDC, UDC, Worldcat, PND…

• Links to resources from cultural environment– Museums, archives– Scientific communities: bibliographic data & research data– Publishers– Europeana and other aggregators

Semantic Annotation

Conclusion?

• Linked Data won’t not solve everything right now

• Just a set of techniques and a vision for better sharing, cross-linking and re-use data, fitting the web

• Which is not bad!

If we stop here, thanks for your attention!

Any (more) questions?

Some references

W3C Library LD Incubator

http://www.w3.org/2005/Incubator/lld• 1-year group• OCLC, LC, VU Amsterdam, DNB, etc.

• help increase global interoperability of library data on the Web

• bringing together people involved in Linked Data—in the library community and beyond

• building on existing initiatives and collaboration tracks for the future

Library LDUse Cases

• LLD use cases and case studies (work in progress)

• JISC cases for open bibliographic data http://obd.jisc.ac.uk

http://www.w3.org/2005/Incubator/lld/wiki/UseCases

Useful vocabularies to express data• Dublin Core• SKOS• BIBO• OAI-ORE• FOAF• MADSIn progress• RDA vocabularies• FRBR@IFLACf. Linked Open VocabulariesNote: vocabularies can be combined and articulated together

dublincore.org/www.w3.org/2004/02/skos/

bibliontology.com/www.openarchives.org/ore/

www.foaf-project.org/www.loc.gov/standards/mads/rdf/

metadataregistry.org/rdabrowse.htm

labs.mondeca.com/dataset/lov/

Datasets

• Controlled vocabularies (thesauri, etc.)LCSH, DDC, Agrovoc, VIAF, GND

• Bibliographic dataNat. Libraries of Hungary, Sweden

• Trying to keep track of some on CKANhttp://ckan.net/group/lld

In the Netherlands

• DEN, Bibliotheek.nl, KB, Vrije Universiteit Amsterdam, Beeld en Geluid, UvA Library

• Amsterdam Museum as Linked Data http://semanticweb.cs.vu.nl/lod/am/

• Dutch Culture Link http://sites.google.com/site/dclod11/

• Dublin Core 2011http://dcevents.dublincore.org/index.php/IntConf/dc-2011

Pictures• http://www.europeana.eu/portal/record/

03903/8C5C6AEFF6B50DCCEDF6A23A99DD3A2D66AEB2CC.html• http://www.europeana.eu/portal/record/03912/

E9666896A50FDDE5F7F15A17C11219A7FBCBBC50.html(Europeana links give access to resources on original sites)

First Demo pointers

• American LCSH http://id.loc.gov• French RAMEAU: http://stitch.cs.vu.nl/rameau• German SWD: http://d-nb.info/gnd/ • Agrovoc: http://aims.fao.org/ • STW: http://zbw.eu/stw/ • DBPedia: http://dbpedia.org/