PRESS RELEASE: “HOBBIT so far.” is now available

cropped-Hobbit_Logo_Claim_2015_rgb_300_130The latest release informs about the conferences our team attended in 2016 as well as about the published blogposts. Furthermore it gives a short analysis about the survey by which we are able to verify requirements of our benchmarks and the new HOBBIT plattform. Last but not least the release gives a short outlook to our plans in 2017 including the founding of the HOBBIT association.

Have a look at the whole press release on the HOBBIT website .

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4th Big Data Europe Plenary at Leipzig University


The meeting, hosted by our partner InfAI e. V., took place on the 14th to the 15th of December at the University of Leipzig.
The 29 attendees in total, including 15 partners, discussed and reviewed the progress of all work packages in 2016 and planned the activities and workshops taking place in the next six months.

On the second day we talked about several societal challenge pilots in the fields of AgroKnow, transport, security etc. It’s been the last plenary for this year and we thank everybody for their work in 2016. Big Data Europa and our partners are looking forward to 2017.

The next Plenary Meeting will be hosted by VU Amsterdam and will take place in Amsterdam, in June 2017.

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SANSA 0.1 (Semantic Analytics Stack) Released

Dear all,

The Smart Data Analytics group /AKSW are very happy to announce SANSA 0.1 – the initial release of the Scalable Semantic Analytics Stack. SANSA combines distributed computing and semantic technologies in order to allow powerful machine learning, inference and querying capabilities for large knowledge graphs.


You can find the FAQ and usage examples at

The following features are currently supported by SANSA:

  • Support for reading and writing RDF files in N-Triples format
  • Support for reading OWL files in various standard formats
  • Querying and partitioning based on Sparqlify
  • Support for RDFS/RDFS Simple/OWL-Horst forward chaining inference
  • Initial RDF graph clustering support
  • Initial support for rule mining from RDF graphs

We want to thank everyone who helped to create this release, in particular, the projects Big Data Europe, HOBBIT and SAKE.

Kind regards,

The SANSA Development Team

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AKSW wins award for Best Resources Paper at ISWC 2016 in Japan

iswc2016Our paper, “LODStats: The Data Web Census Dataset”, won the award for Best Resources Paper at the recent conference in Kobe/Japan, which was the premier international forum for Semantic Web and Linked Data Community. The paper presents the LODStats dataset, which provides a comprehensive picture of the current state of a significant part of the Data Web.

Congrats to  Ivan Ermilov, Jens Lehmann, Michael Martin and Sören Auer.

Please find the complete list of winners here.


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AKSW Colloquium, 28.11.2016, NED using PBOH + Large-Scale Learning of Relation-Extraction Rules.

In the upcoming Colloquium, November the 28th at 3 PM, two papers will be presented:

Probabilistic Bag-Of-Hyperlinks Model for Entity Linking

Diego Moussallem will discuss the paper “Probabilistic Bag-Of-Hyperlinks Model for Entity Linking” by Octavian-Eugen Ganea et. al. which was accepted at WWW 2016.

Abstract:  Many fundamental problems in natural language processing rely on determining what entities appear in a given text. Commonly referenced as entity linking, this step is a fundamental component of many NLP tasks such as text understanding, automatic summarization, semantic search or machine translation. Name ambiguity, word polysemy, context dependencies and a heavy-tailed distribution of entities contribute to the complexity of this problem. We here propose a probabilistic approach that makes use of an effective graphical model to perform collective entity disambiguation. Input mentions (i.e., linkable token spans) are disambiguated jointly across an entire document by combining a document-level prior of entity co-occurrences with local information captured from mentions and their surrounding context. The model is based on simple sufficient statistics extracted from data, thus relying on few parameters to be learned. Our method does not require extensive feature engineering, nor an expensive training procedure. We use loopy belief propagation to perform approximate inference. The low complexity of our model makes this step sufficiently fast for real-time usage. We demonstrate the accuracy of our approach on a wide range of benchmark datasets, showing that it matches, and in many cases outperforms, existing state-of-the-art methods

Large-Scale Learning of Relation-Extraction Rules with Distant Supervision from the Web

Afterward, René Speck will present the paper “Large-Scale Learning of Relation-Extraction Rules with
Distant Supervision from the Web”
by Sebastian Krause et. al. which was accepted at ISWC 2012.

Abstract: We present a large-scale relation extraction (RE) system which learns grammar-based RE rules from the Web by utilizing large numbers of relation instances as seed. Our goal is to obtain rule sets large enough to cover the actual range of linguistic variation, thus tackling the long-tail problem of real-world applications. A variant of distant supervision learns several relations in parallel, enabling a new method of rule filtering. The system detects both binary and n-ary relations. We target 39 relations from Freebase, for which 3M sentences extracted from 20M web pages serve as the basis for learning an average of 40K distinctive rules per relation. Employing an efficient dependency parser, the average run time for each relation is only 19 hours. We compare these rules with ones learned from local corpora of different sizes and demonstrate that the Web is indeed needed for a good coverage of linguistic variation

About the AKSW Colloquium

This event is part of a series of events about Semantic Web technology. Please see for further information about previous and future events. As always, Bachelor and Master students are able to get points for attendance and there is complimentary coffee and cake after the session.

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Accepted paper in AAAI 2017

aaai-bannerHello Community! We are very pleased to announce that our paper “Radon– Rapid Discovery of Topological Relations” was accepted for presentation at the Thirty-First AAAI Conference on Artificial Intelligence (AAAI-17), which will be held in February 4–9 at the Hilton San Francisco, San Francisco, California, USA.

In more detail, we will present the following paper: “Radon– Rapid Discovery of Topological Relations” Mohamed Ahmed Sherif, Kevin Dreßler, Panayiotis Smeros, and Axel-Cyrille Ngonga Ngomo

Abstract. Datasets containing geo-spatial resources are increasingly being represented according to the Linked Data principles. Several time-efficient approaches for discovering links between RDF resources have been developed over the last years. However, the time-efficient discovery of topological relations between geospatial resources has been paid little attention to. We address this research gap by presenting Radon, a novel approach for the rapid computation of topological relations between geo-spatial resources. Our approach uses a sparse tiling index in combination with minimum bounding boxes to reduce the computation time of topological relations. Our evaluation of Radon’s runtime on 45 datasets and in more than 800 experiments shows that it outperforms the state of the art by up to 3 orders of magnitude while maintaining an F-measure of 100%. Moreover, our experiments suggest that Radon scales up well when implemented in parallel.

This work is implemented in the link discovery framework LIMES and has been supported by the European Union’s H2020 research and innovation action HOBBIT (GA no. 688227) as well as the BMWI Project GEISER (project no. 01MD16014).

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AKSW Colloquium, 17.10.2016, Version Control for RDF Triple Stores + NEED4Tweet

In the upcoming Colloquium, October the 17th at 3 PM, two papers will be presented:

Version Control for RDF Triple Stores

Marvin Frommhold will discuss the paper “Version Control for RDF Triple Stores” by Steve Cassidy and James Ballantine which forms the foundation of his own work regarding versioning for RDF.

Abstract:  RDF, the core data format for the Semantic Web, is increasingly being deployed both from automated sources and via human authoring either directly or through tools that generate RDF output. As individuals build up large amounts of RDF data and as groups begin to collaborate on authoring knowledge stores in RDF, the need for some kind of version management becomes apparent. While there are many version control systems available for program source code and even for XML data, the use of version control for RDF data is not a widely explored area. This paper examines an existing version control system for program source code, Darcs, which is grounded in a semi-formal theory of patches, and proposes an adaptation to directly manage versions of an RDF triple store.

NEED4Tweet: A Twitterbot for Tweets Named Entity Extraction and

Afterwards, Diego Esteves will present the paper “NEED4Tweet: A Twitterbot for Tweets Named Entity Extraction and
Disambiguation” by Mena B. Habib and Maurice van Keulen which was accepted at ACL 2015.

Abstract: In this demo paper, we present NEED4Tweet, a Twitterbot for named entity extraction (NEE) and disambiguation (NED) for Tweets. The straightforward application of state-of-the-art extraction and disambiguation approaches on informal text widely used in Tweets, typically results in significantly degraded performance due to the lack of formal structure; the lack of sufficient context required;
and the seldom entities involved. In this paper, we introduce a novel framework
that copes with the introduced challenges. We rely on contextual and semantic features more than syntactic features which are less informative. We believe that disambiguation can help to improve the extraction process. This mimics the way humans understand language.

About the AKSW Colloquium

This event is part of a series of events about Semantic Web technology. Please see for further information about previous and future events. As always, Bachelor and Master students are able to get points for attendance and there is complimentary coffee and cake after the session.

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LIMES 1.0.0 Released

Dear all,

the LIMES Dev team is happy to announce LIMES 1.0.0.

LIMES, the Link Discovery Framework for Metric Spaces, is a link discovery framework for the Web of Data. It implements time-efficient approaches for large-scale link discovery based on the characteristics of metric spaces. Our approaches facilitate different approximation techniques to compute estimates of the similarity between instances. These estimates are then used to filter out a large amount of those instance pairs that do not suffice the mapping conditions. By these means, LIMES can reduce the number of comparisons needed during the mapping process by several orders of magnitude. The approaches implemented in LIMES include the original LIMES  algorithm for edit distances, HR3, HYPPO and ORCHID.

Additionally, LIMES supports the first planning technique for link discovery HELIOS, that minimizes the overall execution of a link specification, without any loss of completeness. Moreover, LIMES implements supervised and unsupervised machine-learning algorithms for finding accurate link specifications. The algorithms implemented here include the supervised, active and unsupervised versions of EAGLE and WOMBAT.





User manual:

Developer manual:


What is new in LIMES 1.0.0:

  • New Controller that supports manual and graphical configuration
  • New machine learning pipeline: supports supervised, unsupervised and active learning algorithms
  • New dynamic planning for efficient link discovery
  • Updated execution engine to handle dynamic planning
  • Added support for qualitative (Precision, Recall, F-measure etc.) and quantitative (runtime duration etc.) evaluation metrics for mapping evaluation, in the presence of a gold standard
  • Added support for configuration files in XML and RDF formats
  • Added support for pointsets metrics such as Mean, Hausdorff and Surjection
  • Added support for MongeElkan, RatcliffObershelp string measures
  • Added support for Allen’s algebra temporal relations for event data
  • Added support for all topological relations derived from the DE-9IM model
  • Migrated the codebase to Java 8 and Jena 3.0.1

We would like to thank everyone who helped to create this release. We also acknowledge the support of the SAKE  and HOBBIT projects.

Kind regards,

The LIMES Dev team


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DL-Learner 1.3 (Supervised Structured Machine Learning Framework) Released

Dear all,

the Smart Data Analytics group at AKSW is happy to announce DL-Learner 1.3.

DL-Learner is a framework containing algorithms for supervised machine learning in RDF and OWL. DL-Learner can use various RDF and OWL serialization formats as well as SPARQL endpoints as input, can connect to most popular OWL reasoners and is easily and flexibly configurable. It extends concepts of Inductive Logic Programming and Relational Learning to the Semantic Web in order to allow powerful data analysis.

GitHub page:

DL-Learner is used for data analysis tasks within other tools such as ORE and RDFUnit. Technically, it uses refinement operator based, pattern-based and evolutionary techniques for learning on structured data. For a practical example, see It also offers a plugin for Protégé, which can give suggestions for axioms to add.

In the current release, we added a large number of new algorithms and features. For instance, DL-Learner supports terminological decision tree learning, it integrates the LEAP and EDGE systems as well as the BUNDLE probabilistic OWL reasoner. We migrated the system to Java 8, Jena 3, OWL API 4.2 and Spring 4.3. We want to point to some related efforts here:

We want to thank everyone who helped to create this release, in particular we want to thank Giuseppe Cota who visited the core developer team and significantly improved DL-Learner. We also acknowledge support by the recently SAKE project, in which DL-Learner will be applied to event analysis in manufacturing use cases, as well as Big Data Europe and HOBBIT projects.

Kind regards,

Lorenz Bühmann, Jens Lehmann, Patrick Westphal and Simon Bin


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OntoWiki 1.0.0 released

Dear Semantic Web and Linked Data Community,
we are proud to finally announce the releases of OntoWiki 1.0.0 and the underlying Erfurt Framework in version 1.8.0.
After 10 years of development we’ve decided to release the teenager OntoWiki from the cozy home of 0.x versions.
Since the last release of 0.9.11 in January 2014 we did a lot of testing to stabilize OntoWikis behavior and accordingly made a lot of bug fixes, also we are now using PHP Composer for dependency management, improved the testing work flow, gave a new structure and home to the documentation and we have created a neat project landing page.

The development of OntoWiki is completely open source and we are happy for any contribution, especially to the code and the documentation, which is also kept in a Git repository with easy to edit Markdown pages. If you have questions about the usage of OntoWiki besides the documentation you can also use or mailinglist or the stackoverflow tag “ontowiki”.

Please see for further information.

We also had a Poster for advertising the OntoWiki release at SEMANTiCS Conference:

OntoWiki 1.0

Philipp Frischmuth, Natanael Arndt, Michael Martin: OntoWiki 1.0: 10 Years of Development – What’s New in OntoWiki

We are happy for your feedback, in the name of the OntoWiki team,
Philipp, Michael and Natanael

Our Fingers on the Mouse

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