Table 2 Sets of approaches combining CRFs, dictionary matching, and regular expression matching in five different ways.

1

Combines a CRF to identify SYSTEMATIC entities with dictionary matching to identify TRIVIAL, FAMILY, and ABBREVIATION entities, and regular expression matching to identify FORMULA and IDENTIFIER entities.

2

Combines individual CRFs to identify SYSTEMATIC and TRIVIAL entities with dictionary matching to identify FAMILY and ABBREVIATION entities, and regular expression matching to identify FORMULA and IDENTIFIER entities.

3

Uses a single CRF to identify SYSTEMATIC, TRIVIAL, FAMILY, ABBREVIATION, FORMULA and IDENTIFIER entities.

4

Combines individual CRFs to identify SYSTEMATIC, TRIVIAL, FAMILY, ABBREVIATION, and FORMULA entities with an individual regular expression matching to identify IDENTIFIER entities.

5

Uses a single CRF to identify SYSTEMATIC, TRIVIAL, FAMILY, ABBREVIATION, FORMULA and IDENTIFIER entities and specifically labels each class of entity.