1,387 research outputs found
Mostly-Unsupervised Statistical Segmentation of Japanese Kanji Sequences
Given the lack of word delimiters in written Japanese, word segmentation is
generally considered a crucial first step in processing Japanese texts. Typical
Japanese segmentation algorithms rely either on a lexicon and syntactic
analysis or on pre-segmented data; but these are labor-intensive, and the
lexico-syntactic techniques are vulnerable to the unknown word problem. In
contrast, we introduce a novel, more robust statistical method utilizing
unsegmented training data. Despite its simplicity, the algorithm yields
performance on long kanji sequences comparable to and sometimes surpassing that
of state-of-the-art morphological analyzers over a variety of error metrics.
The algorithm also outperforms another mostly-unsupervised statistical
algorithm previously proposed for Chinese.
Additionally, we present a two-level annotation scheme for Japanese to
incorporate multiple segmentation granularities, and introduce two novel
evaluation metrics, both based on the notion of a compatible bracket, that can
account for multiple granularities simultaneously.Comment: 22 pages. To appear in Natural Language Engineerin
Neural Word Segmentation with Rich Pretraining
Neural word segmentation research has benefited from large-scale raw texts by
leveraging them for pretraining character and word embeddings. On the other
hand, statistical segmentation research has exploited richer sources of
external information, such as punctuation, automatic segmentation and POS. We
investigate the effectiveness of a range of external training sources for
neural word segmentation by building a modular segmentation model, pretraining
the most important submodule using rich external sources. Results show that
such pretraining significantly improves the model, leading to accuracies
competitive to the best methods on six benchmarks.Comment: Accepted by ACL 201
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