Online adaptation strategies for statistical machine translation in post-editing scenarios

One of the most promising approaches to machine translation consists in formulating the problem by means of a pattern recognition approach. By doing so, there are some tasks in which online adaptation is needed in order to adapt the system to changing scenarios. In the present work, we perform an exhaustive comparison of four online learning algorithms when combined with two adaptation strategies for the task of online adaptation in statistical machine translation. Two of these algorithms are already well-known in the pattern recognition community, such as the perceptron and passive-aggressive algorithms, but here they are thoroughly analyzed for their applicability in the statistical machine translation task. In addition, we also compare them with two novel methods, i.e., Bayesian predictive adaptation and discriminative ridge regression. In statistical machine translation, the most successful approach is based on a log-linear approximation to a posteriori distribution. According to experimental results, adapting the scaling factors of this log-linear combination of models using discriminative ridge regression or Bayesian predictive adaptation yields the best performance.

► To analyse online learning algorithms for their applicability in the pattern recognition approach to machine translation. ► To develop new online learning algorithms in the specific task of statistical machine translation. ► To study the different strategies for online adaptation present in statistical machine translation. ► To compare the performance of the algorithms detailed when combined with the different strategies presented. ► To assess the suitability of online adaptation within real-sized tasks.