On Libraries & Linked Data Antoine Isaac UB Utrecht, April 6, 2011

Who am I? Europeana Web & Media Lab, Vrije Universiteit Amsterdam Web & Media Lab W3C Library Linked Data group ( ) W3C Semantic Web Deployment groupW3C Semantic Web Deployment group SKOS

Demo Following one’s nose to subject heading lists as linked data American LCSH French RAMEAU German SWD Agrovoc STW Further on to DBPedia

Demo (fallback option) Subject heading lists as SKOS linked data American LCSH French RAMEAU: German SWD: mapped using manual links from the MACS project Starting from

Linked Data? 1. Use URIs as names for things 2. Use HTTP URIs so that people can look up those names 3. 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,

(Linked) Data Representation That subject heading data follows a link-intensive data model Uniform resource identifiers (URI) Resource Description Framework (RDF)

(Linked) Data Representation Use more-or-less the same standard vocabulary Simple Knowledge Organization System (SKOS) For representing thesauri, classifications, etc. on the Semantic Web

A SKOS graph animals cats UF domestic cats RT wildcats BT animals SN used only for domestic cats domestic cats USE cats wildcats

SKOS mappings SKOS provides conceptual links to bridge across different contexts KOS 1: animals cats wildcats KOS 2: animal human object

Links in the data

Growing interest for linked data in the library community

Linked Library Cloud beginning 2008 [Ross Singer, Code4Lib2010]

Linked Library “sector” in 2010 Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch.

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 difficult Intrinsic quality problems: correctness, coverage Especially when data is so heterogeneous 100s of formats From flat 5-fields records to 100-nodes XML trees Language issue! We currently use a simple, flat interoperability format Quick-win quickly showing its limits

We can better use institutions’ original metadata Accommodate their different practices Data structures and semantics Access objects via a semantic layer of vocabularies for subjects, persons, places… Semantic ThoughtLab: experimenting solutions

Towards semantics-enabled search Building 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

Prototype: Europeana Thought Lab

Clustering of results

Baseline: matching concepts' label Controlled place name from a vocabulary at the Rijskmuseum Metadata for the object

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 - match Information 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 vocabularies Concept “Giza” narrower than concept “Egypte” Mapping/alignment between CH vocabularies Louvre’s “Égypte” equivalent to Rijksmuseum’s “Egypte” Enrichment of existing metadata The string “Egypt” in a metadata record indicates the concept of Egypt defined in Rijksmuseum thesaurus

Challenge #1: Linking

Manual mapping of large vocabularies is labour-intensive LCSH, RAMEAU and SWD mapped in the MACS project SWD and DDC mapped in the CRISS-CROSS project Automatic linking is not perfect but can help STW, AGROVOC… Some studies (and further pointers) for automatic library thesaurus alignment in the STITCH project

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?

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 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 LD Use Cases LLD use cases and case studies (work in progress) JISC cases for open bibliographic data

Useful vocabularies to express data Dublin Core SKOS BIBO OAI-ORE FOAF MADS In progress RDA vocabularies Cf. Linked Open Vocabularies Note: vocabularies can be combined and articulated together dublincore.org/ bibliontology.com/ metadataregistry.org/rdabrowse.htm labs.mondeca.com/dataset/lov/

Datasets Controlled vocabularies (thesauri, etc.) LCSH, DDC, Agrovoc, VIAF, GND Bibliographic data Nat. Libraries of Hungary, Sweden Trying to keep track of some on CKAN

In the Netherlands DEN, Bibliotheek.nl, KB, Vrije Universiteit Amsterdam, Beeld en Geluid, UvA Library Amsterdam Museum as Linked Data Dutch Culture Link Dublin Core

Pictures A23A99DD3A2D66AEB2CC.html A23A99DD3A2D66AEB2CC.html 5A17C11219A7FBCBBC50.html 5A17C11219A7FBCBBC50.html (Europeana links give access to resources on original sites)

First Demo pointers American LCSH French RAMEAU: German SWD: Agrovoc: STW: DBPedia: