For instance, on en → f r, PBSMT tuned on 100 parallel sentences obtains a BLEU score of 26.42 on newstest 2014, compared to 27.09 with default hyper-parameters, and 28.02 when tuned on the 3000 parallel sentences of newstest 2013.
unless otherwise specified, all PBSMT models considered in the paper use default hyperparameter values, and do not use any parallel resource whatsoever.