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Change Tracking in Knowledge Organization Systems with SKOS-History

When a new version of a vocabulary is published, users want to know "What's new?" and "What has changed?"

Vocabulary managers had differing strategies to answer these questions, relying on internal logs of the vocabulary management system or the intellectual collection of changes deemed relevant. These methods generally are not available to third parties using a vocabulary, or for example, are trying to keep vocabulary mappings up to date. Having vocabularies published in SKOS as RDF triples has changed this situation. Vocabularies can be compared algorithmically, and deltas between versions can be computed. This data can be loaded into a version store and evaluated by SPARQL queries. Therefore, the published versions alone are sufficient to get the differences.

The webinar will explain how you can create a version store, how skos-history interlinks versions and deltas, and how queries can get a grip on added or removed concepts, on changed notations, or on merges and splits of concepts. We will show how aggregated change information about a concept scheme can be obtained, and how the complete change history of a single concept across multiple versions can be traced. Finally, you will learn how you can adapt skos-history queries to the features of a particular concept scheme in which you are interested.


Joachim Neubert is a scientific software developer at the ZBW Leibniz Information Centre for Economics ( He published the STW Thesaurus for economics ( and several other datasets as Linked Open Data. In 2009, he started the SWIB -- Semantic Web for Libraries conference and serves to date as co-chair of its programme committee. As an b invited expertb , he took an active part in the Library Linked Data Incubator Group of the World Wide Web Consortium (W3C). His research interests include knowledge organization systems and authorities, linked data, and web-based information systems and applications, on which he reports once in a while on ZBW Labs (

Osma Suominen is currently working as information systems specialist at the National Library of Finland. He is involved in publishing library data as Linked Data, maintaining the thesaurus and ontology service, and leading development of the Skosmos vocabulary browser used in Finto. He is currently also assisting FAO (UN), CABI (UK), and NAL (US) in creating a Global Agricultural Concept Scheme by merging their existing thesauri, using Linked Data tools and approaches. Osma Suominen earned his doctoral degree at Aalto University while doing research on semantic portals and quality of controlled vocabularies within the FinnONTO series of projects. His past accomplishments include the Skosify vocabulary analysis and quality improvement tool, and, the Linked Data service of Aalto University.

Webinar & Slides