baseNP: doesn’t contain any recursive parts.
chunking: build the tree for the sentence
Level of representation:
* Brown Corpus (level1: pos)
* Penn Trecbank (level2: sys)
* PropBank (level3: sen)
* Framenet (level4: )
All of these need lots of human labor.
h(x) = argmin(y in Y) E_(y~p(Y|X))[l(y,x,Y)]
l (y*,x,y) = 1 – delta(y,y*)
H(x) = argmax_(y in Y) Pr(y|x)
min_(h in H) E_{p}[loss(X;Y;h)] + model complexity(h)
Empirical risk = 1/N SUM_{I = 1}^{N}loss(x,y*,h)
recognize speech
wreak a nice beach
an ice beach
conditional random fields