Optimising chemical named entity recognition with pre-processing analytics, knowledge-rich features and heuristics

Table 15 Sample tokens and their chemical segment composition.

Token initially recognised as non-chemical	Chemical basic segments	Ratio
polycalcium	poly, calcium	1.0
2-methoxyestradiol	meth, oxy, estra, di, ol	0.89
palytoxin	toxin	0.56

ISSN: 1758-2946