From Athenawiki
Chimaera
Software Description
Chimaera is a software system that supports users in creating and maintaining distributed ontologies on the web. Two major functions it supports are merging multiple ontologies together and diagnosing individual or multiple ontologies. It supports users in such tasks as loading knowledge bases in differing formats, reorganizing taxonomies, resolving name conflicts, browsing ontologies, editing terms, etc. The user manual may be viewed from here.
For a graphical presentation of Chimaera, run through the tutorial or see this movie. To view this movie, first right-click on the link and select the menu item "Save Link As...". After saving this file to your computer, you can then open it in the normal method to view the movie. Chimaera was built on top of the Ontolingua Distributed Collaborative Ontology Environment. .
Source: http://www.ksl.stanford.edu/software/ontolingua/
Ontolingua environment
Ontolingua provides a distributed collaborative environment to browse, create, edit, modify, and use ontologies. The server supports over 150 active users, some of whom have provided us with descriptions of their projects.

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