I came across this interesting paper that make use of the Klink-2 Computer Science Ontology (CSO):

Automatic Classification of Springer Nature Proceedings with Smart Topic Miner

Where can I find an API or something like that to access this ontology. In the paper they have mentioned that it uses the Klink data model available at: http://technologies.kmi.open.ac.uk/rexplore/ontologies/BiboExtension.owl

But, that page does not provide any supporting details, as if how to use it.

Please help me to access this Klink-2 Computer Science Ontology (CSO).

3 Answers 3


It is unlikely that the entire Klink-2 Computer Science Ontology is openly available online.

The authors decide to monetize their research creating Rexplore.
It seems that the generated CSO ontology is a very substantil part of the project.

The demo of Rexplore is available here. Following instructions, one can generate topic trees for different series of Springer proceedings. However, the "Download tree" button is not working.

However, a sample of the ontology is available.

The paper you have linked to references to another paper, which contains this link.

The content of the ZIP archive shows how OWL ontologies looks like.
However, those example ontologies (or rather taxonomies) covers Semantic Web topics only.

As for API for ontologies.

If an ontology is serialized into RDF, then you can make queries with SPARQL.
Languages for querying on more abstract level are DL Query and SQWRL.
There even exists the so-called OWL API.

But first, just open an ontology in Protégé.

Update 1

The 2012 ACM Computing Classification System has been developed as a poly-hierarchical ontology that can be utilized in semantic web applications. It replaces the traditional 1998 version of the ACM Computing Classification System (CCS), which has served as the de facto standard classification system for the computing field.

The full CCS classification tree is freely available for educational and research purposes in these downloadable formats: SKOS (xml), Word, and HTML.


Update 2

The Knowledge Media Institute (KMi) of The Open University and Springer Nature are happy to announce the release of The Computer Science Ontology (CSO).

CSO is a large-scale, automatically generated ontology of research areas in the field of Computer Science. The current version of CSO incorporates 14K topics and over 143K relationships extracted by applying the Klink-2 algorithm on a dataset of about 16M scientific articles.


  • Thanks a lot for your great answer. Does that mean CSO ontology is not publicly available? :)
    – J Cena
    Feb 18, 2018 at 22:51
  • Yes, I think so, but perhaps you could email the authors. Feb 19, 2018 at 4:14
  • Thanks a lot. Please let me know if you are aware of any Computer Science related ontology? :)
    – J Cena
    Feb 19, 2018 at 6:34
  • It seems that you need something like (and that is what the CSO ontology is) a hierarchy of CS subjects interrelated with skos:broader or something like. Unfortunately, Wikidata and DBpedia do not provide such taxonomy. Perhaps ACM Classification Codes will be suitable for you needs, it is easy to create a simple SKOS-taxonomy from them. Feb 19, 2018 at 16:20
  • And perhaps you could extract something from Google Scholar labels, ask on academia.stackexchange.com. Feb 19, 2018 at 16:38

https://gist.github.com/VladimirAlexiev/fafdcb258d067cfed272664d6ae5d982 describes 6 datasets of Science Classification. Will keep it up to date as we progress.

One of them is CSO, which is now publically available. It has about 2-3k CompSci topics. In comparison, MAG has 229k topics in all scientific areas.


The Computer Science Ontology (CSO) is freely available at http://cso.kmi.open.ac.uk/ since 2018, and it can be downloaded in a variety of formats. You can also subscribe to the site and give your feedback about any topic or relationship.

PS: I am the author of the ontology and I would have happily share with you back in 2016. Just send me a mail next time. :)

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