4. The system of claim 1 , wherein said system further comprises a user query receiving subsystem for receiving said query and extracting data for information retrieval to generate a query vector, and an information retrieval subsystem for computing similarities between said document-keyword vectors and said query vector to select said document-keyword vectors.
4. The system of claim 1 , wherein said system further comprises a user query receiving subsystem for receiving said query and extracting data for information retrieval to generate a query vector, and an information retrieval subsystem for computing similarities between said document-keyword vectors and said query vector to select said document-keyword vectors. 5. The system of claim 4 , wherein said best size of a cluster is estimated using said vectors with respect to said user query.