This document discusses linking the Belgium War Press dataset to create a knowledge graph. It outlines transforming the data into Linked Data using the 5 star Open Data plan. This includes assigning URIs, adding semantic relationships and linking to external datasets. It demonstrates querying the knowledge graph to retrieve newspaper titles and related information from DBpedia. Future work includes making the URIs dereferenceable and saving locations with OLR. The goal is to enhance search and discovery of the historical newspaper collection.

1. Let’s talk Linked Data session Open Belgium 2017
Brecht Van de Vyvere | @brechtvdv
Building a knowledge graph of the
Belgium War Press

2. Can I easily link historic papers with
other datasources?

3. Agenda
• hetarchief.be
• Knowledge graph
• 5-star Open Data plan
• Adding context
• Linked Data as a Service
• Future Work

4. Dataset

5. hetarchief.be
“News from the Great War”
• Newspapers 1914 - 1918
• 10+ Content Partners
• Begin 2015: site launched
• Functionality
• Search by keyword
• Map with place of publication
• Collections
1k titles
55k newspapers
300k pages

6. Human-readable interface

7. Policy
1. Metadata
• No restrictions → CC0
2. OCR, documents
• Pictures, short stories…
• Uncertain copyright status
• No license or “terms of use” that minimises restrictions
for re-use
• Disclaimer

8. hetarchief.be
• One of the biggest databases online
• No raw data?
• Title
• Description → OCR from ALTO
• Date created
• Owner
• IDs (carrier, Abraham, VIAA)
• URL image

9. 9
5-stars
Open Data Plan

10. First 3 Stars
• Open License
• Structured
• Non-proprietary
VIAA
DB
VIAA API NodeJS
→ github.com/viaacode/hetarchief2lod
IDs Metadata
CSV
Transform

11. Step 4: URIs for everything
• Map VIAAs internal ID to URI:
• http://data.viaa.be/noid/{id}
• Use ontologies
• BBC → Creative Work Ontology
• schema.org
• Hydra → collections

12. Knowledge graph
• Semantic network
• Concepts
• Relations
• Linked Data
• URIs
• RDF

13. <http://dbpedia.org/page
Albert_I_of_Belgium>
rdfs:type
<http://xmlns.com/
foaf/0.1/Person>
<http://data.viaa.be/
noid/example>
<http://www.bbc.co.uk/ontologies/
creativework#tag>

14. 5-star: link to other sources
• ABRAHAM: catalogue of newspapers in Belgium
<http://anet.be/record/abraham/opacbnc/c:bnc:26>
<http://data.viaa.be/noid/tm71v5c76q_191510XX>
owl:sameAs

15. L’illustration“1915-10-XX”
http://data.viaa.be/noid/
tm71v5c76q_191510XX
cwork:titlecwork:dateCreated
On dit que c'est
notre imagination
et….
cwork:content
cwork:CreativeWork
rdf:type
UGENT
schema:copyrightHolder
schema:inLanguage
en
Basic information triples

16. http://data.viaa.be/noid/
tm71v5c76q
http://data.viaa.be/noid/
tm71v5c76q_191804xx_0003
http://data.viaa.be/noid/
tm71v5c76q_191804xx_0002
http://data.viaa.be/noid/
tm71v5c76q_191804xx_0001
first
last
previous/next
first
memberOf
totalItemsHydra
last
3
first/last

17. Problems
• Node limited to 1.7 GB memory
• OCR too big
• Turtle file: 475 MB max (32k
newspapers)
• Compressed to HDT: 388 MB
• Basic triples with HDT:
• 54k newspapers → 8.2 MB

18. Adding context

19. Connect with other datasources
• Cfr. Europeana, delpher.nl, lab.kbresearch.nl

20. Stanford NER
• 4 types: Location, Organisation, Person and
Other
• Train your model: golden corpus
• Write code that fits your needs
• SPARQL query that matches strings
• REPERTOIRE des COMMUNES et des PRINCIPAUX
HAMEAUX de la ci-devant Belgique
• Difficult to find cultural APIs (cfr.
InFlandersField list of names, Abraham
catalogue)

21. DBpedia Spotlight
• Proof of concept
• Models for all languages (nl, en, fr, de)
NL/FR/EN/DE
trained model
DBpedia
matcher
Stanford NER

22. Results?
• Filter on OCR quality; e.g. <90% assurance
in ALTO
• Wrong time period, e.g. geonames
• Standard models, should be trained
• Use DBpedia knowledge later to filter
“impossible” tags

23. DBpedia Spotlight
• Running your own endpoint is easy:
• java -Xmx8G -jar dbpedia-
spotlight-0.7.1.jar nl http://localhost:2223/
nl/rest
• Or with Docker:
• docker build -f Dockerfile -t
dutch_spotlight .
• docker run -i -p 2223:80 dutch_spotlight
spotlight.sh

24. Linked Data as a Service
• Allow federated queries
• Low server cost
• Be reliable
• Triple Pattern Fragments: a Low-cost
Knowledge Graph Interface for the Web

25. Linked Data Fragments querying
• VIAA is part of the family!
http://data.viaa.be/
ldfhttps://query.wikidata.org/
bigdata/ldf
http://
data.linkeddatafragments.
org/linkedgeodata
http://
data.linkeddatafragments.
org/dbpedia2014
Your browser
Client-side algorithm
GET fragments

26. Demo time!

27. Demo
• Retrieve all newspaper titles:
SELECT DISTINCT ?title
WHERE {
?paper <http://www.bbc.co.uk/ontologies/creativework#title> ?title
}

28. Demo
• Retrieve more info from corresponding
DBpedia URI:
SELECT ?label ?comment
WHERE {
<http://data.viaa.be/noid/2z12n51476_19141120_0001> <http://
www.bbc.co.uk/ontologies/creativework#tag> ?tag .
?db owl:sameAs ?tag .
?db rdfs:label ?label .
?db rdfs:comment ?comment
}

29. Battle of the Somme
• Pages with military leaders from the Battle
of the Somme mentioned + thumbnail:
SELECT ?paper ?o ?thumbnail
WHERE {
<http://dbpedia.org/resource/Battle_of_the_Somme> <http://dbpedia.org/
ontology/commander> ?o .
?paper <http://www.bbc.co.uk/ontologies/creativework#tag> ?ctag .
?o owl:sameAs ?ctag .
?o <http://dbpedia.org/ontology/thumbnail> ?thumbnail .
}

30. Frontpainters
• Semi-automatic generation of collections,
e.g. about frontpainters
SELECT ?newspaper ?artist ?tag ?hetarchief
WHERE {
?artist dc:subject <http://dbpedia.org/resource/
Category:Belgian_war_artists> .
?artist owl:sameAs ?tag .
?newspaper <http://www.bbc.co.uk/ontologies/creativework#tag> ?
tag .
?newspaper <http://www.w3.org/2000/01/rdf-schema#seeAlso> ?
hetarchief
}

31. Conclusion
• Extra search method for our researchers
• NER versus OCR: enhanced findability
• Adding extra information (cfr. Abraham)
requires effort, we need more TPFs
interfaces

32. Future work
• Dereferencable URIs
• http://data.viaa.be/noid/{id}
• Content negotiation
• HTML
• JSON
• RDF
• Save location with OLR
• Suggestions are welcome!

33. Q&A
Brecht Van de Vyvere | @brechtvdv