Theory of alignment generators and applications to statistical machine translation

  • Authors:
  • Raghavendra U. Udupa;Hemanta K. Maji

  • Affiliations:
  • IBM India Research Laboratory, New Delhi;IBM India Research Laboratory, New Delhi

  • Venue:
  • IJCAI'05 Proceedings of the 19th international joint conference on Artificial intelligence
  • Year:
  • 2005

Quantified Score

Hi-index 0.00

Visualization

Abstract

Viterbi Alignment and Decoding are two fundamental search problems in Statistical Machine Translation. Both the problems are known to be NP-hard and therefore, it is unlikely that there exists an optimal polynomial time algorithm for either of these search problems. In this paper we characterize exponentially large subspaces in the solution space of Viterbi Alignment and Decoding. Each of these subspaces admits polynomial time optimal search algorithms. We propose a local search heuristic using a neighbourhood relation on these subspaces. Experimental results show that our algorithms produce better solutions taking substantially less time than the previously known algorithms for these problems.