Supporting Linked Data Production for Cultural Heritage institutes:

The Amsterdam Museum Case Study

Victor de Boer, Jan Wielemaker, Judith van Gent, Michiel Hildebrand, Antoine Isaac, Jacco van Ossenbruggen, Guus Schreiber

EuropeanaConnect

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Aggregator

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“Europeana enables people to explore the digital resources of Europe's museums, libraries, archives and audio-visual collections.’’

www.europeana.eu

From portal… …to data aggregator.

Europeana

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data.europeana.eu

2.4 Million objects exposed as Linked Data.

8 aggregators, 200 institutions, 15 countries

Europeana Semantic Elements converted to RDF Europeana Data Model (EDM)

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Aggregate and convert

Linked data-ify

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Aggregate and convert

Linked data-ify

Convert to Linked dataMapped to EDM

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Methodology and tool stack

• Focus on transparency and interactivity– Reproducability – Both in conversion and alignment

• Maintain detail and complexity of original data

• Interoperability through schema mapping

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Methods

ClioPatria

XMLRDF

1. XML ingestion (OAI)

2. Direct transformation to ‘crude’ RDF

3. Interactive RDF restructuring

4. Create a metadata mapping schema

5. Align vocabularies with external sources

6. Publish as Linked Data

Amalgame

Tools

cliopatria.swi-prolog.org powered by

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Case study:Amsterdam Museum

• Formerly Amsterdam Historic Museum– “The rich collection of works of art,

objects and archaeological finds brings to life the fortunes of Amsterdammers of days gone by and today.”

• In March 2010 published their whole collection online– 73.000 objects– CC license

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Methods

ClioPatria

XMLRDF

1. XML ingestion

2. Direct transformation to ‘crude’ RDF

3. Interactive RDF restructuring

4. Create a metadata mapping schema

5. Align vocabularies with external sources

6. Publish as Linked Data

Amalgame

Tools

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Ingested AM metadata

• Adlib database XML API

• Object metadata • 73.000 objects, 256MB • Nested XML

• Concept Thesaurus• 27.000, 9MB• Different types (geo,motif, event)

• Person Authority File• 67.000 persons, 10MB• Consolidated from object metadata fields• Creators, annotators, reproduction creators,

institutions,

<record priref="10541“ > <acquisition.date>1997</acquisition.date> <dimension> <dimension.type>hoogte</dimension.type> <dimension.unit>cm</dimension.unit> <dimension.value>6</dimension.value> </dimension> …</record>

<record priref="28024“ > <term>Kalverstraat 124</term> <broader_term>Kalverstraat</broader_term> <term.type>GEOKEYW </term.type> </record>

<record priref="6" > <biography>boekverkoper en uitgever van cartografie</biography> <birth.date.start>1659</birth.date.start> <death.date.start>1733</death.date.start> <name>Aa, Pieter van der</name> <nationality>Nederlands</nationality> <use>Aa, Pieter van der (I)</use> </record>

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XMLRDF (1)Syntactic RDF conversion

<record priref="19319 “ > <date>1651</date> <maker>Rembrandt (1606-1669)</maker> <object.type>etsplaat</object.type> …</record>

am:Record_:bn1

“19319 ”

“1651”

priref

date

maker

object.type

“Rembrandt (1606-1669)”

“etsplaat”

XML-Element is attributes + content Map to RDF blank-node + attributes

Attributes → Literals (+xml:lang) Content

If plain → Literal (+xml:lang) Otherwise → RDF blank node (recursive)

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ClioPatria:Intermediate Statistics

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Methods

ClioPatria

XMLRDF

1. XML ingestion

2. Direct transformation to ‘crude’ RDF

3. Interactive RDF restructuring

4. Create a metadata mapping schema

5. Align vocabularies with external sources

6. Publish as Linked Data

Amalgame

Tools

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XMLRDF Graph rewrite rule language

Declarative committed-choice language based on CHR (Constraint Handling Rules) Triples <=> Guard, NewTriples Keep \ Triples <=> Guard, NewTriples

Example

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AM rewriting rules examples

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RDF rewriting conversion<record priref="19319 “ > <date>1651</date> <maker>Rembrandt (1606-1669)</maker> <object.type>etsplaat</object.type> …</record>

am:Record_:bn1

“19319 ”

“1651”

priref

date

am:Personam:p-1234

skos:Conceptam:etsplaat

“1234”

“1606”

am:prirefam:birthdate

“etsplaat”

maker

object.type

“Rembrandt (1606-1669)”

“etsplaat”

am:Recordam:proxy-19319

“19319 ”

“1651”am:priref

am:date

am:maker

am:object.type

“Rembrandt”rda:name

skos:prefLabel

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Some statisticsAmsterdam Museum

Rules Resources Predicaes used

Triples

Object metadata 58 73,447 (Proxies)

100 5,700,371

Thesaurus 23 28,000 (Concepts)

13 601,819

Person Auth List 2 66,966 (Persons)

21 301,143

558,161 Proxy-Concept relations 80,432 Proxy-Person relations 243,532 Proxy-Proxy relations

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Methods

ClioPatria

XMLRDF

1. XML ingestion

2. Direct transformation to ‘crude’ RDF

3. Interactive RDF restructuring

4. Create a metadata mapping schema

5. Align vocabularies with external sources

6. Publish as Linked Data

Amalgame

Tools

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Mapping to EDM

am:proxy_22093 “Job Cohen”am:contentPersonName

rdfs:subPropertyOf

dcterms:subject

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Europeana Data Model (EDM)

• Dublin Core for metadata representation– creator, date, title etc.

• SKOS for vocabularies– preferredLabel, hasBroader, etc.

• RDA Group 2 elements for persons– dateOfBirth, name etc.

• OAI-ORE to allow for aggregations etc.

• Some EDM-specific properties– edm:wasPresentAt, …

110 rdfs:subPropertyOf

triples relating AM predicates

to EDM predicates

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Methods

ClioPatria

XMLRDF

1. XML ingestion

2. Direct transformation to ‘crude’ RDF

3. Interactive RDF restructuring

4. Create a metadata mapping schema

5. Align vocabularies with external sources

6. Publish as Linked Data

Amalgame

Tools

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Amalgame Alignment Platform

semanticweb.cs.vu.nl/amalgame

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AM Alignments

• 3500+ links put in RDF– 143 places linked to

GeoNames– 1076 persons linked to

ULAN (VIAF)– 34 persons linked to

DBPedia– 2498 concepts

AATNed.

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Methods

ClioPatria

XMLRDF

1. XML ingestion

2. Direct transformation to ‘crude’ RDF

3. Interactive RDF restructuring

4. Create a metadata mapping schema

5. Align vocabularies with external sources

6. Publish as Linked Data

Amalgame

Tools

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Architecture

RDF(s) storage

HTTP server

SPARQL

Prolog

Web interface

SPARQL-app Browser

Logic

Purl.org redirect

http://semanticweb.cs.vu.nl/europeana/

cliopatria

Content negotiation@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix ore: <http://www.openarchives.org/ore/terms/> .@prefix ens: <http://www.europeana.eu/schemas/edm/> .@prefix ahm: <http://purl.org/collections/nl/am/>

ahm:proxy-66970a ore:Proxy ;ahm:title "Zegelstempel Felix Meritis"@nl ;ahm:material ahm:t-12463 ,

ahm:t-5447 ;ahm:objectCategory ahm:t-5504 ;ahm:objectName ahm:t-13817 ,

ahm:t-8489 ;ahm:objectNumber "KA 7653.1" ;ahm:priref "66970" .

ahm:proxy-66972a ore:Proxy ;ahm:acquisitionDate "0000" ;ahm:title "Zegelstempel mogelijk van

familiewapen"@nl .

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

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Wrapping up

Methodology• Stay as close as possible to original (XML) metadata• Separate syntactic transformation, semantic interpretations• Interactive workflow, simple steps• Use rdf schema to map to interoperability layer• Keep provenance, reproducability

Tools• XMLRDF Realised clean workflow for RDF production.• Amalgame: Interactive and transparent vocablary alignment• ClioPatria Semantic server: statistics at any moment + Full

expressivity of Some Prolog

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Issues

• Validate with real collection managers– Making good rules is sometimes hard– Graphical tools can help

• Integrate in normal collection workflow (tools)– LD as another view on the data– Live updates

• RDFS reasoning needed to have interoperability

v.de.boer@vu.nlhttp://semanticweb.cs.vu.nl/lod/am/

ClioPatria: the SWI-Prolog RDF toolkit (includes XMLRDF and Amalgame packages)

http://cliopatria.swi-prolog.org

amsterdammuseum.nl

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