Document indexation is an essential task achieved by archivists or automatic
indexing tools. To retrieve relevant documents to a query, keywords describing
this document have to be carefully chosen. Archivists have to find out the
right topic of a document before starting to extract the keywords. For an
archivist indexing specialized documents, experience plays an important role.
But indexing documents on different topics is much harder. This article
proposes an innovative method for an indexing support system. This system takes
as input an ontology and a plain text document and provides as output
contextualized keywords of the document. The method has been evaluated by
exploiting Wikipedia's category links as a termino-ontological resources