Twelve distributional similarity measures were computed over the health-care corpus using the aforementioned variations (Section 4.1), where two feature representations were considered: in the UMLS each natural language phrase may be mapped not to a single CUI, but to a tuple of CUIs.
in the first representation, each feature vector coordinate counts the number of times a tuple of CUIs was mapped to the term instantiating the template argument, and in the second representation it counts the number of times each single CUI was one of the CUIs mapped to the term instantiating the template argument.