23. A system for knowledge discovery from a set of free-text documents, the system comprising: means for extracting semi-structured meta-data from the set of free-text documents; means for filtering the semi-structured meta-data to identify a set of key concepts and a corresponding set of key relations between the key concepts, the set of key concepts corresponding to the plurality of concepts; means for deriving at least one set of sub-concepts corresponding to the set of key concepts based upon data within a domain knowledge base, means for formulating training samples, each training sample including a vector representing a sub-concept and a vector representing a key concept; and means for deriving a set of associations between a set of vectors representing a sub-concept and at least one vector representing a key concept, wherein neither the set of text documents nor the semi-structured meta-data mention the set of associations, and wherein the set of associations corresponds to discovered knowledge that is extractable by a knowledge interpreter.
23. A system for knowledge discovery from a set of free-text documents, the system comprising: means for extracting semi-structured meta-data from the set of free-text documents; means for filtering the semi-structured meta-data to identify a set of key concepts and a corresponding set of key relations between the key concepts, the set of key concepts corresponding to the plurality of concepts; means for deriving at least one set of sub-concepts corresponding to the set of key concepts based upon data within a domain knowledge base, means for formulating training samples, each training sample including a vector representing a sub-concept and a vector representing a key concept; and means for deriving a set of associations between a set of vectors representing a sub-concept and at least one vector representing a key concept, wherein neither the set of text documents nor the semi-structured meta-data mention the set of associations, and wherein the set of associations corresponds to discovered knowledge that is extractable by a knowledge interpreter. 28. The system according to claim 23 wherein the means for identifying the set of key relations comprises means for selecting the set of key relations according to frequency of appearance of the set of key relations in the semi-structured meta-data.