The document describes how the Amsterdam Museum converted its collection metadata into Linked Open Data using a methodology and set of tools. The metadata was extracted from XML sources, transformed into RDF using XMLRDF, restructured interactively using rules in ClioPatria, mapped to the Europeana Data Model, and aligned with external vocabularies using Amalgame. The resulting LOD graph of over 5 million triples representing the museum's 73,000 objects is published and queried using a SPARQL endpoint.

1. 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

2. Aggregator
2

3. Europeana
“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.
3

4. 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)
4

5. Linked data-ify
Aggregate and convert
5

6. Linked data-ify
Convert to
Linked data
Mapped to EDM
Aggregate and convert
6

7. 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
7

8. Methods Tools
ClioPatria
1. XML ingestion (OAI)
2. Direct transformation to ‘crude’ RDF
XMLRDF
3. Interactive RDF restructuring
4. Create a metadata mapping schema
5. Align vocabularies with external sources Amalgame
6. Publish as Linked Data
8
cliopatria.swi-prolog.org powered by

9. 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
9

10. Methods Tools
ClioPatria
1. XML ingestion
2. Direct transformation to ‘crude’ RDF
XMLRDF
3. Interactive RDF restructuring
4. Create a metadata mapping schema
Amalgame
5. Align vocabularies with external sources
6. Publish as Linked Data
10

11. Ingested AM metadata
<record priref="10541“ >
• Adlib database XML API <acquisition.date>1997</acquisition.date>
<dimension>
<dimension.type>hoogte</dimension.type>
<dimension.unit>cm</dimension.unit>
• Object metadata <dimension.value>6</dimension.value>
</dimension>
• 73.000 objects, 256MB …
• Nested XML </record>
• Concept Thesaurus <record priref="28024“ >
<term>Kalverstraat 124</term>
• 27.000, 9MB <broader_term>Kalverstraat</broader_term>
<term.type>GEOKEYW </term.type>
• Different types (geo,motif, event) </record>
• Person Authority File <record priref="6" >
• 67.000 persons, 10MB <biography>boekverkoper en uitgever van
• Consolidated from object metadata fields cartografie</biography>
<birth.date.start>1659</birth.date.start>
• Creators, annotators, reproduction <death.date.start>1733</death.date.start>
creators, institutions, <name>Aa, Pieter van der</name>
<nationality>Nederlands</nationality>
<use>Aa, Pieter van der (I)</use>
</record>
11

12. XMLRDF (1)
Syntactic RDF conversion
<record priref="19319 “ >
<date>1651</date>
<maker>Rembrandt (1606-1669)</maker>
<object.type>etsplaat</object.type> priref “19319 ”
… date
</record>
“1651”
am:Record
_:bn1 “Rembrandt (1606-1669)”
object.type “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) 12

13. ClioPatria:
Intermediate Statistics
13

14. Methods Tools
ClioPatria
1. XML ingestion
2. Direct transformation to ‘crude’ RDF
XMLRDF
3. Interactive RDF restructuring
4. Create a metadata mapping schema
Amalgame
5. Align vocabularies with external sources
6. Publish as Linked Data
14

15. XMLRDF Graph rewrite rule
language
 Declarative committed-choice language
based on CHR (Constraint Handling
Rules)
 Triples <=> Guard, NewTriples
 Keep Triples <=> Guard, NewTriples
15

16. Example

17. AM rewriting rules examples
17

18. RDF rewriting conversion
<record priref="19319 “ >
<date>1651</date>
<maker>Rembrandt (1606-1669)</maker>
<object.type>etsplaat</object.type> priref “19319 ”
… date
</record>
“1651”
am:Record
_:bn1 “Rembrandt (1606-1669)”
object.type “etsplaat”
“19319 ”
am:date “1651”
“1234”
am:priref
am:Record am:birthdate
am:maker am:Person
am:proxy-19319 “1606”
am:p-1234
rda:name “Rembrandt”
skos:Concept
am:etsplaat
“etsplaat”
skos:prefLabel 18

19. Some statistics
Amsterdam Museum
Rules Resources Predicaes Triples
used
Object metadata 58 73,447 100 5,700,371
(Proxies)
Thesaurus 23 28,000 13 601,819
(Concepts)
Person Auth List 2 66,966 21 301,143
(Persons)
558,161 Proxy-Concept relations
80,432 Proxy-Person relations
243,532 Proxy-Proxy relations 19

20. Methods Tools
ClioPatria
1. XML ingestion
2. Direct transformation to ‘crude’ RDF
XMLRDF
3. Interactive RDF restructuring
4. Create a metadata mapping schema
Amalgame
5. Align vocabularies with external sources
6. Publish as Linked Data
20

21. Mapping to EDM
dcterms:subject
rdfs:subPropertyOf
am:contentPersonName
am:proxy_22093 “Job Cohen”
21

22. 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, …
22

23. Methods Tools
ClioPatria
1. XML ingestion
2. Direct transformation to ‘crude’ RDF
XMLRDF
3. Interactive RDF restructuring
4. Create a metadata mapping schema
Amalgame
5. Align vocabularies with external sources
6. Publish as Linked Data
23

24. Amalgame Alignment Platform
24
semanticweb.cs.vu.nl/amalgame

25. 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.
25

26. Methods Tools
ClioPatria
1. XML ingestion
2. Direct transformation to ‘crude’ RDF
XMLRDF
3. Interactive RDF restructuring
4. Create a metadata mapping schema
Amalgame
5. Align vocabularies with external sources
6. Publish as Linked Data
26

27. Architecture
SPARQL-app Browser
Purl.org
redirect
SPARQL Web interface
HTTP server
RDF(s) storage Logic
Prolog
27
http://semanticweb.cs.vu.nl/europeana/

28. 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-66970
a 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-66972
a ore:Proxy ;
ahm:acquisitionDate "0000" ;
ahm:title "Zegelstempel mogelijk van
familiewapen"@nl .
28

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

31. 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
31

32. 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
32

33. http://semanticweb.cs.vu.nl/lod/am/
v.de.boer@vu.nl
amsterdammuseum.nl
?
ClioPatria: the SWI-Prolog RDF toolkit
(includes XMLRDF and Amalgame packages)
http://cliopatria.swi-prolog.org