We further implement head binarization on the English parse trees and apply the achieved binary trees to another string-to-tree system (abbreviated as s2t-hb) with the same settings of s2t.
just as FIGURE 4(c) shows, there are only 3 frontier nodes in the former case ( [0,1] [ Practically, we need a supervised POS tagger, which impairs the unsupervised property of our tree structure to s y unsup utomatic ome extent.