For example, from the sentence in Figure 1 for the labelling of f 24 = de with a 24 = 16 (for e 16 = of ) we might detect the following feature: Note that it is the target word indexed by a t , rather than the index itself, which determines whether the feature is active, and thus the sparsity of the index label set is not an issue.
we trained Model 4 in both directions on the two language pairs.