For instance, in addition to (研究(YanJiu), NN, HF) and (研究(YanJiu), VV, HF), (研究(YanJiu), VA, LF) and (研究(YanJiu), CD, LF) may appear as entries in the word unigram list, due to mis-tagging by the baseline POS-tagger.
we further impose a restriction based on the frequency as follows: if the number of entries with a HF label ≥ threshold, only the entries with HF will be selected, and if the sum of entries with a HF or M F label ≥ threshold, the entries with either HF or M F will be selected, otherwise, all of the entries in L m will be selected.