Document Frequency Factor – multiplier that is applied to Number of Documents variable in TF-cIDF term weight model. If DFCDocument Frequency Factor - multiplier that is applied to Number of Documents variable in TF-cIDF term weight model. If DFC = 0, then it is TF model, if DFC=1, then it is typical TF-IDF.... = 0, then it is TF model, if DFC=1, then it is typical TF-IDF.