Previous attempts have dealt with the overfitting problem by limiting the maximum phrase length (DeNero et al., 2006;Marcu and Wong, 2002) and by smoothing the phrase probabilities by lexical models on the phrase level (Ferrer and Juan, 2009).
the produced phrase alignment can be given as a single best alignment, as the n-best alignments or as an alignment graph representing all alignments considered by the decoder.