“…According to a recent work of ours [23], we used the 12 most frequent semantic types to construct 12 semantic context sub-features that can cover more than 80% of the UMLS terms in our dataset: “Amino Acid, Peptide, or Protein,” “Body Part, Organ, or Organ Component,” “Disease or Syndrome,” “Finding,” “Medical Device,” “Organic Chemical,” “Pharmacologic Substance,” “Sign or Symptom,” “Therapeutic or Preventive Procedure.” “Finding,” “Pharmacologic Substance,” and “Disease or Syndrome.” The method for calculating these sub-features is similar to that for the feature POS context features. We give a concrete example of the semantic context feature in Table S2 in the Supplementary Material.…”