Abstract: The method of estimating the relevance of a document with respect to a concept comprises calculating (32) a relevance function of the concept with respect to said document on the basis of a known predetermined semantic neighborhood of the concept. It further comprises calculating an ambiguity function of said concept in said document, which ambiguity function is different from the relevance function, said calculation being an estimation based on the presence in the document of different meanings of the concept. The method follows on from a preliminary step of detecting ambiguous concepts in a database.

Abstract: This system for predictive analysis of digital data time flows associated with text information (18) comprises means (12) for automatically predicting values (24) of a digital data time flow from past values (22) of said flow. It further comprises means (14) for analyzing text information (18) to supply the prediction means (12) with a weighted concept vector (20) associated with the past values (22) of the digital data time flow.

Abstract: The method of estimating the relevance of a document with respect to a concept comprises calculating (32) a relevance function of the concept with respect to said document on the basis of a known predetermined semantic neighborhood of the concept. It further comprises calculating an ambiguity function of said concept in said document, which ambiguity function is different from the relevance function, said calculation being an estimation based on the presence in the document of different meanings of the concept. The method follows on from a preliminary step of detecting ambiguous concepts in a database.

Abstract: The indexing and search system comprises means (10) for storing an indexing base (24), means (22) for indexing resources (18) to create and update the indexing base (24), means (40) for searching for resources and adapted to interrogate the indexing base (24) on the basis of a request, and request-extender means (38) for obtaining an extended request on the basis of an initial request (34) formulated by a user and including initial terms (R1), by adding to said initial request (34) terms which are neighbors to the initial terms. The extender means (38) further comprise means (36) for limiting the extension of the initial request by adding thereto only terms that are neighbors to initial terms that are not general, i.e. Terms that do not have too great a number of neighbors. Means (20) for generalizing indexing may also be implemented in the invention.

Abstract: This system for predictive analysis of digital data time flows associated with text information (18) comprises means (12) for automatically predicting values (24) of a digital data time flow from past values (22) of said flow. It further comprises means (14) for analyzing text information (18) to supply the prediction means (12) with a weighted concept vector (20) associated with the past values (22) of the digital data time flow.

Abstract: This system for assisting generating queries comprises means for generating a query using logic operators to link selected concepts. The generation means comprise means for determining logic operators of the query on the basis of the nature of predetermined semantic links between the selected concepts.