Protégé is a free, open source ontology editor and knowledge-base framework.
The Protégé platform supports two main ways of modeling ontologies via the Protégé-Frames and Protégé-OWL editors. Protégé ontologies can be exported into a variety of formats including RDF(S), OWL, and XML Schema.
Protégé is based on Java, is extensible, and provides a plug-and-play environment that makes it a flexible base for rapid prototyping and application development.
The OntoLT approach aims at a more direct connection between ontology engineering and linguistic analysis. OntoLT is a Protégé plug-in, with which concepts (Protégé classes) and relations (Protégé slots) can be extracted automatically from linguistically annotated text collections. It provides mapping rules, defined by use of a precondition language that allow for a mapping between linguistic entities in text and class/slot candidates in Protégé.
S. Braun, A. Schmidt, and V. Zacharias. Mensch & Computer - 7. Fachübergreifende Konferenz (M&C 2007), Munich, Germany, Oldenbourg Verlag, (2-5 September 2007)
S. Braun, A. Schmidt, and V. Zacharias. 4th Conference on Professional Knowledge Management - Experiences and Visions, Workshop on Productive Knowledge Work (ProKW 07), (28-30 March 2007)