Summarizing (Moore, 2004), we note that this work improves substancially upon the classical IBM Model 1 by introducing a set of heuristics, among which are to (1) modify the lexical parameter dictionaries (2) introduce an initialization heuristic (3) modify the standard IBM 1 EM algorithm by introducing smoothing (4) tune additional parameters.
we stress that the main concern of this work is not just heuristicbased empirical improvement, but also structured learning.