Master project Rianne Nieland: Talking to Linked Data

[This post was written by Rianne Nieland. It describes her MSc. project supervised  by myself]

People in developing countries cannot access information on the Web, because they have no Internet access and are often low literate. A solution could be to provide voice-based access to data on the Web by using the GSM network.

afbeeldingIn my master project I have investigated how to make general-purpose data sets efficiently available using voice interfaces for GSM. To achieve this, I have developed two voice interfaces, one for Wikipedia and one for DBpedia. I have made two voice interfaces with two different kinds of input data sources, namely normal web data and Linked Data, to be able to compare them.

To develop the two voice interfaces, I first did requirements elicitation from literature and developed a user interface and conversion algorithms for Wikipedia and DBpedia concepts. With user tests the users evaluated the two voice interfaces, to be able to compare them on speed, error rate and usability.

[Rianne’s thesis presentation slides can be found on slideshare and is embedded below. Her thesis is attached here: Eindversie-Paper-Rianne-Nieland-2057069]


[slideshare id=37310122&w=476&h=400&sc=no]

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VU E-history datathon links up multiple datasets

A bit belated, but on April 2nd, we organized a ‘datathon’: a one day event where we sat down with pizzas and laptops to link up multiple digital history datasets. The Dutch Ships and Sailors data was one of those datasets, other participants included Niels Ockeloen from the BiographyNet project, Albert Merono from the CEDAR project and Chris Dijkshoorn who brought Linked Data from the Naturalis and Rijksmuseum collections. External participants included Ivo Zandhuis from

Linking and eating pizza

The end results are promising:

  • 5000+ links from people in the BiographyNet RDF data to people in the Rijksmuseum RDF data.
  • 2 links from Dutch Ships and Sailors to Rijksmuseum collections
  • 61 links from Dutch Ships and Sailors Ranks to CEDAR Hisco ‘occupation’ URIs were made
  • 1320 links of CEDAR municipalities (by Amsterdamse Code) to municipalities
  • 33 links of ICONCLASS (used by Rijksmuseum) to HISCO occupations

We hope to expand this datacloud in the near future and show the added value of such an interconnected digital history cloud for historical research and the general public. You can read more at Albert’s blog or on the blog of Ivo Zandhuis’ Hic Sunt Leones

The e-history Linked Data cloud visualized
The e-history Linked Data cloud visualized

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DownScale 2013 workshop

DOWNSCALE 2013, the 2nd international workshop on downscaling the Semantic Web was held on 19-9-2013 in Geneva, Switzerland and was co-located with the Open Knowledge Conference 2013. The workshop seeks to provide first steps in exploring appropriate requirements, technologies, processes and applications for the deployment of Semantic Web technologies in constrained scenarios, taking into consideration local contexts. For instance, making Semantic Web platforms usable under limited computing power and limited access to Internet, with context-specific interfaces.

Downscale group picture
Downscale group picture

The workshop accepted three full papers after peer-review and featured five invited abstracts. in his keynote speech, Stephane Boyera of SBC4D gave a very nice overview of the potential use of Semantic Web for Social & Economic Development. The accepted papers and abstracts can be found in the  downscale2013 proceedings, which will also appear as part of the OKCon 2013 Open Book.


We broadcast the whole workshop live on the web, and you can actually watch the whole thing (or fragments) via the embedded videos below.

After the presentations, we had fruitful discussions about the main aspects of ‘downscaling’. The consensus seemed to be that Downscaling involved the investigation and usage of Semantic Web technologies and Linked Data principles to allow for data, information and knowledge sharing in circumstances where ‘mainstream’ SW and LD is not feasible or simply does not work. These circumstances can be because of cultural, technical or physical limitations or because of natural or artificial limitations.


The figure  illustrates a first attempt to come to a common architecture. It includes three aspects that need to be considered when thinking about data sharing in exceptional circumstances:

  1. Hardware/ Infrastructure. This aspect includes issues with connectivity, low resource hardware, unavailability, etc.
  2.  Interfaces. This concerns the design and development of appropriate interfaces with respect to illiteracy of users or their specific usage. Building human-usable interfaces is a more general issue for Linked data.
  3. Pragmatic semantics. Developing LD solutions that consider which information is relevant in which (cultural) circumstances is crucial to its success. This might include filtering of information etc.

The right side of the picture illustrates the downscaling stack.

Continue reading

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CSWS2013 summer school and keynote in Shanghai

ShanghaiLast week, Knud Moeller from datalysator and I were invited to give a set of lectures about Linked Data in the CSWS 2013 summer school in Shanghai, China. As far as we are concerned the summer school was a success. About 60 students received three mornings worth of lectures about the principles and practice of Linked Data from the two of us. In the afternoon, they heard talks about Semantic Web efforts from the likes of Baidu and Google.

Interested students Because of the unavailability/-reachability of twitter, facebook, slideshare and wordpress in China, the lecture materual can be found are online as pdfs through a HTML page at my VU homepage.

I also had the honour of giving a keynote speech about Linked Data for Cultural Heritage and Digital History in the main conference. Those slides can be found on Slideshare.

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Verrijkt Koninkrijk at the Soeterbeeck E-humanities workshop

The Soeterbeeck monastery with two e-humanistsLast week, I presented our work on the Verrijkt Koninkrijk project at the E-humanities workshop in the Soeterbeeck monastery which was organised by the university of Nijmegen and the e-humanities group of KNAW.

It was a very pleasant get-together with some nice talks and hands on sessions. Alice Dijkstra from NWO  presented a number of opportunities for getting funding for e-humanities projects. She mentioned some obvious candidates (vernieuwingsimpuls,…) and some less obvious ones (the hopefully upcoming CLARIAH programme, which would continue CLARIN and DARIAH).

The two hands on sessions were nice but showed that there is a more general issue with e-humanities that ‘nice tools’ are being developed but that these tools remain solutions to a single problem. Next to that they are either nice from a computer science or from a historical science viewpoint but it is hard to do exciting and historical science at the same time. This is reenforced by the issue that historical scientists rarely know what type of tools they want at the beginning of a project. A more interactive and cyclical approach makes sense for both parties. The BiographyNet idea of putting the researchers from different backgrounds in the same room would be one solution. The other in my view is the development of more general-purpose query environments .

In my poster presentation I showed how I tried to do that with Verrijkt Koninkrijk and I think for a more or less generic data analysis interface is also a good idea.

You can download the VK poster Abstract as well as the actual Poster.

Links to some of the web-demo’s we tried:

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Dutch Ships and Sailors project started

a very unofficial DSS logo i madeLast week saw the kickoff of the new Clarin NL-funded project “Dutch Ships and Sailors”(*). This project will run for one year and gives me the opportunity to work with historians from both VU and Huygens ING on applying Linked Data principles to Dutch maritime-historical data. From the official description:

As a sea-faring nation, a large portion of Dutch history is found on the water. However, much of the digitized historical source material is still scattered across many databases and archives. This curation and demonstrator project aims to bring together the rich maritime historical data preserved in the many different databases. We propose a (semantic) web-based infrastructure

that will house various maritime-historical datasets. We will provide a tool chain and methodology for converting legacy datasets. The infrastructure includes common vocabularies to normalize and enrich existing data. Links are established between the datasets and to other relevant datasets on the Web. Although the infrastructure will be set up to facilitate 25+ identified datasets, we initially populate the infrastructure with four selected datasets. These will allow us to investigate two case studies in order to answer the historical research question “To what extent did patterns of shipping and recruitment in the Dutch maritime sector change over the course of the 18th and 19th centuries?”

(*) the project’s official title is Dutch Ships and Seamen, but we think this is potentially less problematic 🙂

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The Verrijkt Koninkrijk Hackathon Report

On Friday, March 8th, we organized a Verrijkt Koninkrijk Linked Data Hackathon at the Intertain Lab of VU Amsterdam. The event was co-sponsored by the Network Institute. The goal of the hackathon was to allow third party developers to produce (ideas for) innovative applications beyond the Verrijkt Koninkrijk core research questions. We especially encouraged the use of the Linked Data produced in the project.


As organizers, we are very happy with the produced prototypes. The benefits are following:

  • The produced applications show the (unexpected) reusability of the VK (Linked) Open Data. The applications produced or suggested give new browsing opportunities, links to other datasets or show how the data can be used in a completely novel context.The hackathon revealed that indeed the data is usable for external developers using the documentation provided. Some bugs were found, some of which could be fixed during the hackathon.
  • Important concepts around data quality were articulated by the users. Although it falls outside of the scope of this project, subsequent curation of the dat should involve considering ways of allowing experts or amateurs to correct errors in the data.
  •  The VK project data is made known to researchers and developers from related projects, for example that of Agora or BiographyNed. We expect that this ensures future use of the data by related projects.

We here present short descriptions of what the six hacker teams cooked up. Two prize winners were announced by the jury, for “best use of data” and “coolest app” respectively. The jury consisted of Kees Ribbens and Edwin Klijn from NIOD, Serge ter Braake and Victor de Boer from VU. More photos of the event can be seen at



Niels used the data from the Named Entity index to create a history browser which allows the user to browse information about WWII on basis of persons, locations, organisations, etc. (the NER classes). For this he reused the Agora Touch demonstrator. When a class is chosen a list of entities is shown with images which are resolved through the alignment with DBpedia. Niels used the LDtogo framework to map the selected data on the API interface of the Agora demo.


This group set out to to recreate the network of important people of the Netherlands during WWII and their quotes in fake Facebook profiles, trying to imitate the reality of their time. We feed automatically these streams with the contents of the VK datasets: little Cliopatria and Python snippets retrieve data from SPARQL endpoints, resolve the structured XML texts, extract the quotes and expose them using the Facebook Graph API. View the project on GitHub and see the live demo at

image031Lourens aligned the VK data with that of Agora Rijksmuseumusing the Amalgame alignment tool. This is used to link VK data to RM images using the Rijksmuseum API via (results shown here (pdf)) He furthermore started to use the Verrijkt Koninkrijk data to add links to VK from within our AGORA demo that is an event centered browser for the Rijksmuseum content. Very rough results show a AGORA demo entry for Duitsland.

image028The application of Chris van Aart shows how the monument data from Vier en Vijf Mei can be browsed using the Cube browser on IOS. THis allows for multi-faceted browsing between Dutch war monuments. By flipping the screen, one can actually look at the RDF data!

image029Michiel built a web map application showing the liberation of Nijmegen in 1944. 1940s data and current maps scan be superimposed over eachother therefore showing for example what part of the city was damaged during the liberation. Further additions include 17,19 and 20th Century maps. A demo can be seen at An attempt was made to include Vier en Vijf Mei monument data in this dataset

image018Willem presented the idea to visualise the VK data using the InContext RDF visualizer for enriched publications. Unfortunately, due to time constraints, Willem did not succeed in getting everything up and running.  [screencast]




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Verrijkt Koninkrijk Hackathon Instructions

This post will provide all the participants of the Verrijkt Koninkrijk Hackathon with the information and data they need to start building great applications.

On this Piratepad, I suggest we all note down the progress and results: []

The text

In this deliverable document [ dx1- deliverable pdf], you can find more detailed information about (the origin of) the data.

The Verrijkt Koninkrijk Data concerns Dr Loe de Jong’s Het Koninkrijk der Nederlanden in de Tweede Wereldoorlog and was based on the PDFs as provided by NIOD at . The books have been OCRed and transformed to structured XML by researchers from the Universiteit van Amsterdam. This data is available through A search interface is available at  A resolver server was installed which responds by presenting the structure (in XML) when presented with a URL. For example, is resolved to the XML fragment of that paragraph. Removing the last number of the identifier (43) results in its broader section, etcetera. Paragraphs are the smallest logical units (also, a page is not a logical unit).

Linked Data

We provide two RDF ‘stepping stones’ into the book text. The ‘Back of the Book index’ and the ‘Named Entities index’. Both are SKOS vocabularies and consist of terms pointing to URIs. These vocabularies are linked to external sources as well. All RDF is available as Linked Data at the VK Semantic Layer at The base namespace for the VK/NIOD triples is (abbreviated as niod:). Datasets, mapping sets and schemata are all loaded as separate named graphs (

A SPARQL endpoint is also available at with an interactive SPARQL editor available at http://semanticweb. You can login with “hacker”/”hacker” (if needed).

Back of the book index (BotB index)

The BotB index consists of 15,234 SKOS Concepts, consolidated from the manual index. They link to RDF blank nodes using the niod:pageRef predicate. The blank node links to individual paragraphs using niod:parRef predicates.  An example is shown below.


The BotB index is partially aligned with the NIOD thesaurus (see below), GeoNames, Cornetto and AATNed. The BotB index, the schema, the alignments are found in separate RDF turtle files

Named Entity index (NE index)

This SKOS vocabulary consists of 88,243 concepts, resulting of  Named Entity recognition. The NEs are of type person, location, organisation, misc, product and event. They link into the text through direct niod:pRef links. An example is shown below.


The NE concepts are partially aligned with DBPedia (through wikilinks established during the NER process), with GeoNames (locations only), with GTAA and the NIOD thesaurus. There is also mapping to the BotB index (can be used to use a ‘higher quality’ subset).

Example SPARQL Queries

This page lists a number of sparql queries that exploit some of the links presented above. It accompanies a paper and deliverable.

Other data sources in the semantic layer


Within the project, we are very much interested in the concept of pillarization and how Loe de Jong describes it. For this reason, we have added a turtle file what links Pillar concepts (Protestants, Jews, Communists, etc) to persons, organisations etc. found in the BotB index. This is a manual list of 60 links, which was semi-automatically expanded to 254 links. You can find the original list  here and the expanded one here.

We did a number of  analyses using this data, a (Dutch) PDF document describing the results can be found here [zuilen (pdf)].


Het Koninkrijk is licensed under the Creative Commons Naamsvermelding 3.0 Nederland licentie. The VK Linked Data are NIOD thesaurus are also available under that licenseV. The VM monument data is available under the CC0 Publieke Domein Dedicatie verklaring license

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Verrijkt Koninkrijk Hackathon

HackathonOn Friday March 8, I will organize a small ‘hackathon’ workshop sponsored by the Network Institute in the context of the Verrijkt Koninkrijk project. In this project, we have created a linked data set for “Het Koninkrijk der Nederlanden in WoII” and linked it to some other datasets. We have shown some nice applications but would really like to show how this linked data can be used to create all kinds of nice applications/mashups/visualisations. If you, or any of your students, would like to join in, please let me know! A real hackathon has pizza, coke and prizes so I will definitely make sure that these things are present in our hackathon as well! The hackathon is the whole friday from 10h-17.30 in the Intertain Lab of the VU but you can obviously join half a day or just pop in. If you want to have a sneak peek at the data: here is The Verrijkt Konikrijk Semantic Layer and here’s the search interface (non-semantic, still very nice) Please send me a mail at ( or leave a message below if you are interested in hacking along, so I can order enough pizza’s 🙂


  • Chris van Aart (2CoolMonkeys)
  • Michiel van Dijk (2CoolMonkeys)
  • Michiel Hildebrand (VU Web and Media – Data2Sematics)
  • Niels Ockeloen (VU Web and Media – BiographyNed project)
  • Lourens van der Meij (VU Web and Media – Agora project)
  • Johan van Doornik (UvA ILPS)
  • Albert Meronyo (VU Knowledge Representation and Reasoning)
  • Wouter Beek (VU Knowledge Representation and Reasoning)
  • Kees Ribbens (NIOD)
  • Tim Veken (NIOD)
  • Willem Melder (Beeld en Geluid)

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Verrijkt Koninkrijk Semantic Layer update: now with more DBPedia!


The Verrijkt Koninkrijk Semantic Layer (which has gotten a small makeover) now is expanded with 13,160 links to the Dutch version of DBPedia ( The Named Entities that have been identified by the UvA recognizers have been converted to SKOS and are loaded in the semantic layer. The wikipedia links, also from the UvA algorithms, have been converted to owl:sameAS links to Dutch and English DBPedia. To allow for some nice SPARQL querying, I have fetched the RDF triples for the linked Dutch DBPedia concepts (interactive SPARQL endpoint at

An example of such a nice SPARQL query is this one, which retrieves all paragraphs in Loe de Jong’s text (retrievable through the resolver) that mention a person that was (or later became) a Prime minister (limited to the first 100 results).

PREFIX dcterms: < >
PREFIX niod: < >
PREFIX skos: < >
PREFIX dbp-prop: < >
PREFIX dbp-res: < >

?entity niod:nerClass niod:nerclass-per;
owl:sameAs ?dbpedia_entry;
niod:pRef ?pref.
?dbpedia_entry dbp-prop:functie dbp-res:Minister-president_van_Nederland.

Or this next one, that lists for each of the found named entities of type ‘event’ an image depicting that event.

PREFIX dcterms: < >
PREFIX niod: < >
PREFIX skos: < >
PREFIX dbp-prop: < >
PREFIX foaf: < >

?event niod:nerClass niod:nerclass-eve;
owl:sameAs ?dbpedia_entry;
niod:pRef ?pref.
?dbpedia_entry foaf:depiction ?picture.

Again, all results should be taken with a grain of salt, since many OCR, conversion and linking-errors occur. The quality of the DBPedia conversion is unknown and outside of the scope of the Verrijkt Koninkrijk project.

[update: Links have been updated to]

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