7. The computer-implemented method of claim 5 , further comprising determining a respective conditional independence for each query based on the query vector generated for the query.
8. The computer-implemented method of claim 7 , wherein the conditional independence is determined based on a statistical test selected from a group consisting of a test based on term-frequency/inverse-document-frequency (tf-idf), a test based on mutual information, a χ 2 test, a t-student test, a test based on pointwise mutual information (PMI), and a G-test.