News and Updates on the KRR Group
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The KR&R group investigates modelling and representation of different forms of knowledge and reasoning, as found in a large variety of AI systems. We have an interest in both applications and theory. We study theoretical properties of knowledge representation and reasoning formalisms, but are also involved in developing practical knowledge-based systems. Recently, we have been very active in developments around the Semantic Web.

Posts on this website are continuously aggregated from project and member blogs.

Source: Semantic Web world for you
Following the discussion I had after my previous posts, here is a bit more structured explanation of the ideas: Please feel free to ping me and/or comment on this post if you too think it’s a good idea Filed under: Visualisation

On Monday the 7th of October the Knowledge, Reasoning and Representation and the Web&Media research groups of the Free University Amsterdam joined for their biweekly Semantic Web (SW) meeting. The topic was on the purpose of using HTTP URIs for denoting SW resources and on the implications for archiving Linked Data (LD).

An important aspect of archiving LD is that in archiving the LD is decoupled from its native Web environment (thus the title of the talk). The two most important Web-based properties that are lost in the process are (1) authority and (2) dereferenceability. We first discussed the relevance of both these properties.


Source: Data2Semantics

Our website with additional material for our paper: “A Fast Approximation of the Weisfeiler-Lehman Graph Kernel for RDF Data” has won the Open Science Award at ECML/PKDD 2013. The jury praised the submission as “a perfect example of open science”.

A goal of the Data2Semantics project is to provide resuable software to support semantic enrichment of data. Therefore, the software used for the paper uses existing well-known libraries (SESAME, LibSVM) and was set up into three distinct projects from the start. The heart of software is the proppred library, which contains all the code for doing property prediction using graph kernels on RDF data. Some additional support code for handling RDF is in the d2s-tools project. All the code to run the experiments from the paper(s) is in a separate project called kernelexperiments. This setup allows for easy replication of the (and doing new) experiments and easier integration of the property prediction on RDF library into other projects.

For the future, we aim to provide even more scientific openess via the experimental machine learning platform that we are developing. One of the aims of the platform is to make experimentation easier, without introducing too much overhead. Furthermore, we wil export provenance of the experiments in the Prov-O format. This provenance is visualized using Prov-O-Viz (also developed in Data2Semantics), allowing researchers to gain better insight into the experiments without having to study the code.

protege logo +Apache Jena + YASGUI


This year we again have a nice group of students (almost 70) following the 3rd year bachelor Semantic Web course. Until this year it was quite a hassle to combine the bits and pieces to create a complete workflow starting from ontology creation (in Protégé) to having a nice SPARQL endpoint that reasons in OWL over the ontology+instances.

Like the previous years, the instructors (Stefan Schlobach and Ronald Siebes) updated the assignment by the latest developments regarding available toolkits and software.  We were surprised that it was very easy to integrate these latest tools and are now able to do the following within 30 minutes on any machine:

- create a simple ontology in Protégé

- install a sparql endpoint with OWL reasoning (Jena-Fuseki)

- import the ontology

- connect this local endpoint with Yasgui (

- do via Yasgui a federated query combining results from our local endpoint together with results from other endpoints (e.g. DBPedia)

Conclusion: it is now in reach of many people to get, without a lot of suffering, a nice Semantic Web infrastructure up-and-running, and connect it with the vast amount of external Linked-data from various endpoints.

The Semantic Web works!

Here you can find a manual to do this yourself and hopefully share the conclusion.


Source: Semantic Web world for you
Yesterday I was sitting in a very interesting meeting with some experts in data visualisation. There was a lot of impressive things presented and the name of Wii remote and Kinect were mentioned a couple of time. As I observed so far, these devices are used as cheap way to get sensors. And they certainly […]

Source: Data2Semantics

Paul Groth co-authored an article about altmetrics in the Elsevier Library Connect newsletter for librarians. The newsletter reaches 18,000 librarians in 138 countries around the world.

Academic research and publishing have transitioned from paper to online platforms, and that migration has continued to evolve from closed platforms to connected networks. With this evolution, there is growing interest in the academic community in how we might measure scholarly activity online beyond formal citation.

See more at:

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Source: Data2Semantics

As a complement to two papers that we will present at the ECML/PKDD 2013 conference in Prague in September we created a webpage with additional material.

The first paper: “A Fast Approximation of the Weisfeiler-Lehman Graph Kernel for RDF Data” was accepted into the main conference and the second paper: “A Fast and Simple Graph Kernel for RDF” was accepted at the DMoLD workshop.

We include links to the papers, to the software and to the datasets used in the experiments, which are stored in figshare. Furthermore, we explain how to rerun the experiments from the papers using a precompiled JAR file, to make the effort required as minimal as possible.

Source: Semantic Web world for you
One visiting the Netherlands will inevitably stumble upon some “BakFiets” in the streets. This Dutch speciality that seems to be the result from cross-breeding a pick-up with a bike can be used from many things from getting the kids around to moving a fridge. Now, let’s consider a Dutch bike shop that sells some Bakfiets […]

Source: Semantic Web world for you
Yesterday was the closing event of the Pilot Linked Open Data project. A significantly big crowd of politicians, civil servants, hackers, SME owners, open data activists and researchers gathered in the very nice building of the RCE in Amersfoort to hear about what has been done within this one year project lead by Erwin Folmer. […]

Source: Data2Semantics

This june 10 and 11, the Data2Semantics team locked itself in a room in the Amsterdam Public Library to build a first version of the Data2Semantics Golden Demo: a pipeline for publishing enriched data (‘semantics’) directly from Dropbox to Figshare, integrated in the Linkitup webservice.

In two days, we built and integrated:

Watch the video!


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