The OntoSim library
Participants : Jérôme David [ Contact ] , Jérôme Euzenat.
OntoSim is a library offering similarity and distance measures betwwen ontology entities as well as between ontology themselves. It materialise our work towards better ontology proximity measures  .
There are many reasons for measuring a distance between ontologies. For example, in semantic social network when a peer looks for a particular information, it could be more appropriate to send to query peers having quite close ontology because it will be easier to translate query and there are more chance that such a peer have the information of interest  . OntoSim provides a framework for designing various kinds of similarities. In particular, we differentiated similarities in the ontology space from those in the alignment space. The latter ones make use of available alignments in a network of ontologies while the former only rely on ontology data. OntoSim is provided with 4 entity measures which can be combined using various aggregation schemes (average linkage, Hausdorff, maximum weight coupling, etc.), 2 kinds of vector space measures (boolean and TF.IDF), and 4 alignment space measures. In addition, the framework can embeds external similarity libraries which can be combined to our owns.
OntoSim is based on an ontology interface allowing for using ontology parsed with different API.
The OntoSim is written in Java and is available under the LGPL license at http://ontosim.gforge.inria.fr .