Modelling the Lexicon in Unsupervised Part of Speech Induction
Table 1: M-1 Accuracy on the WSJ Corpus: Comparison of the accuracy of each of the samplers with and without the language model emission prior on the English WSJ Corpus. The second column reports run time in hours where available*. Note the Lex-HMM+LM model matches the PYP-1HMM+LM approximation despite finishing in half the time. The abbreviations in parentheses indicate that the results were reported in CGS10 [Christodoulopoulos et al.2010] and BBDK10 [Berg-Kirkpatrick et al.2010] *CGS10 reports that the MEMM model takes approximately 40 hours on 16 cores.
['Sampler', 'M-1 Accuracy', 'Time (h)']
Treebank Wall Street Journal corpus. Blunsom and Cohn \shortciteblunsom11acl found that the Local PYP-HMM+LM sampler is unable to mix, achieving accuracy below 50%, therefore it has been left out of this analysis. The Lex-HMM+LM model achieves the same accuracy as the state-of-the-art PYP-1HMM+LM approximation. The Lex-HMM+LM’s focus on only the most likely tags for each word type allows it to finish training in half the time as the PYP-1HMM+LM approximation without any artificial restrictions on the number of tags per type.