Data and Knowledge Group

― Knowledge Representation and Reasoning



PAGOdA exploits a hybrid approach to answering conjunctive queries over OWL 2 ontologies that combines a datalog reasoner with a fully-fledged OWL 2 reasoner in order to provide scalable "pay as you go" performance. It delegates the bulk of the computation to RDFox and resorts to expensive reasoning by HermiT only as necessary to fully answer the query.

Currently, RDFox is used as the datalog reasoner and HermiT is used as the full OWL 2 reasoner.


PAGOdA with a command line interface can be downloaded below.

By downloading the sources and/or binaries of PAGOdA, you agree to the following academic licence. If the provided package doesn't work on your machine, you need to compile RDFox yourself following the instruction on and replace JRDFox.jar in the downloaded jar file. If you want to use PAGOdA as a library in your project, you could download this pagoda.jar and import it in your project. Please make sure that you also add all dependencies to your project. If you would like to contribute to the project, you can fork the PAGOdA project on GitHub.

Using PAGOdA

Command is of the following form

where the data file is required to be in turtle format and queries in SPARQL syntax.

For more information, please refer to this guide.


Lastest Datasets

Please check our evaluation page for JAIR 2015 submission.

Past Datasets

Ontologies, datasets and queries that have used for DL 2014 can be downloaded here:


Yujiao Zhou, Yavor Nenov, Bernardo Cuenca Grau, Ian Horrocks

Key Publications

  • Yujiao Zhou, Yavor Nenov, Bernardo Cuenca Grau and Ian Horrocks PAGOdA: Pay-as-you-go Ontology Query Answering Using a Datalog Reasoner. Technical Report.
  • Yujiao Zhou, Yavor Nenov, Bernardo Cuenca Grau and Ian Horrocks Pay-as-you-go OWL Query Answering Using a Triple Store. AAAI 2014.
  • Yujiao Zhou, Yavor Nenov, Bernardo Cuenca Grau and Ian Horrocks Complete Query Answering Over Horn Ontologies Using a Triple Store. ISWC 2013
  • Yujiao Zhou, Bernardo Cuenca Grau, Ian Horrocks, Zhe Wu and Jay Banerjee Making the Most of your Triple Store: Query Answering in OWL 2 Using an RL Reasoner. WWW2013