However for remedy, many of the current word alignment methods combine the results of both alignment directions, via intersection or grow-diag-final heuristic, to improve the alignment reliability (Koehn et al., 2003;Liang et al., 2006;Ayan et al., 2006;DeNero et al., 2007).
the second method uses the impurity method, which was motivated by the method of decision tree.