Neural Machine Translation with Reconstruction
Table 4: Evaluation of translation quality. “Oracle” is the best BLEU score that the k-best translation candidates can achieve on all the test sets. “*” indicate statistically significant difference (p<0.01) from the baseline “RNNSearch (Beam=10)”.
['[BOLD] Model', '[BOLD] Beam', '[BOLD] Tuning', '[BOLD] MT05', '[BOLD] MT06', '[BOLD] MT08', '[BOLD] All', '[BOLD] Oracle']
RNNSearch significantly outperforms Moses by 2.2 BLEU points on average, indicating that it is a strong baseline NMT system. This is mainly due to the introduction of two advanced techniques. Increasing beam size leads to decreasing translation performances on test sets, which is consistent with the result on the validation set. We compare our methods with “RNNSearch (Beam=10)” in the following analysis, since it yields the best performance in the baseline systems.