For example, in a segmentation task using the IOB2 notation, the k-th local feature in f (x, y, i) can be defined as if x i is the word "boy", and y i is the label "B" 0 otherwise With parameter w, the best output sequenceŷ for an input sequence x can be found by calculating the best score:ŷ 3 Online Training We propose to estimate the parameter w in an online manner.
we use the online passiveaggressive algorithm (Crammer et al., 2006).