Lattice Transformer for Speech Translation
Table 5: Ablation Experiment BLEU Results. The rows of the Lattice LSTM and the Lattice Transformer represent the 1-best hypothesis fine-tuning, and the BLEUs are evaluated on 1-best inputs and on lattice inputs for the others. The colored BLEU values come from Table 2 and 3.
['Model', 'Fisher dev2', 'Fisher test', 'Callhome evltest']
Model Ablation Study We conduct an ablation study to examine the effectiveness of every module in the lattice transformer. We gradually add one module from a standard transformer model to our most complicated lattice transformer. Furthermore, the superimposed application of marginal scores in both encoder and decoder can gain an additional promotion, compared to individual applications. However, the use of forward and backward scores has no significantly extra rewards in this situation. Perhaps due to overfitting, the most complicated lattice transformer on the Callhome of smaller data size cannot achieve better BLEUs than simpler models.