In addition to the traditional hiero system, we also compare with the topic-specific lexicon translation method in Zhao and Xing (2007).
the lexicon translation probability is adapted by: we simplify the estimation of p(e|f, z = k) by directly using the word alignment corpus with  table 3: Percentage of topic-sensitive rules of various types of rule according to source-side ("Src") and targetside ("tgt") topic distributions.