Conditional Random Fields
		• Supervised graphical model that blends sequence labeling with maximum entropy classification –  A reasonable first baseline to improve upon. –  SVMs also a reasonable approach but CRFs do sequence labeling, not classification. –  Classification done per token, over sentences. –  A “Not applicable” tag applies to all tokens not of interest. • We use the implementation from CRF++ (Kudo, 05) –  Easy to use interface. –  No feature selection* (still can be improved).