Table 4 Types of features
From: Combination of conditional random field with a rule based method in the extraction of PICO elements
Semantic features | |
|---|---|
f1 | Number of words in the sentence that are in the age, race or gender keywords list |
f2 | Number of words belonging to the UMLS semantic group «Disorders» |
f3 | Number of words belonging to the UMLS semantic group «Procedures» or «Chemicals & Drugs» |
f4 | Number of words that are in the Outcome keywords list |
Structural features | |
f5 | Number of words of the sentence that are in the title |
f6 | Number of words of the sentence that are in the abstract’s « keywords » |
f7 | Sentence header |
f8 | Sentence length (number of words) |
f9 | Sentence relative position |
Lexical feature | |
f10 | The current word and its POS belongs to the bag-of-words |