Adaptation of Long-Unit-Word Analysis System to Different Part-Of-Speech Tagset
Paper · 2014 · Shunsuke Kozawa, Kiyotaka Uchimoto and Yasuharu Den
Summary
The paper examines how to reuse an existing analyzer for Japanese long-unit words (LUWs) on a corpus with a different part-of-speech scheme. The authors take an LUW analyzer originally built for the Corpus of Spontaneous Japanese (CSJ), which uses a flat school-grammar tagset, and adapt it to the Balanced Corpus of Contemporary Written Japanese (BCCWJ), which uses the hierarchical UniDic tagset. Assuming correct short-unit-word (SUW) input, they make four changes. First, they add hierarchical features generalized to higher POS levels. Second, they replace rule-based rewriting with SVM-based models that predict POS, conjugation type and conjugation form. Third, they add BCCWJ-specific cues, namely word origin and circled-character markers. Fourth, they redefine the chunking labels so that category information is tied to the last SUW of each LUW. In experiments, the improved method beat the original approach on BCCWJ and also helped on CSJ. The work matters because it identifies what must change in an analyzer when the tagset changes. The authors also release the open-source tool Comainu.
Key points
- Tagset differences:
- CSJ has 15 POS, 59 conjugation types and 8 conjugation forms, all in a flat scheme.
- BCCWJ/UniDic uses a 4-level POS hierarchy with 54 tags at the finest level, 115 conjugation types and 36 conjugation forms.
- Original method: Uchimoto & Isahara's approach treats LUW identification as sequence chunking over SUWs. It uses the labels Ba/Ia/B/I and applies rewrite rules as post-processing.
- Tools: The chunker was trained with CRF++, and the category-estimation models with YamCha (SVM, polynomial kernel of degree 3, one-versus-rest).
- Comainu:
- It is trained on the BCCWJ core data: 45,342 sentences, 828,133 LUWs and 1,047,069 SUWs.
- It accepts plain text, which it pre-processes with MeCab and UniDic, or SUW sequences as input.
- The chunking model can use either CRF or SVM.
- Missing results: The exact accuracy scores were in the part of the paper omitted from the provided text, so they are not reported here.
Institutions
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 works
🧭 Topics 1Research subjects and languages the work is about.Part-of-speech tagging · 126 works
Cite
Cite as Shunsuke Kozawa, Kiyotaka Uchimoto and Yasuharu Den. 2014. Adaptation of Long-Unit-Word Analysis System to Different Part-Of-Speech Tagset. Journal of Natural Language Processing.
@article{kozawa2014adaptation,
title = {{Adaptation of Long-Unit-Word Analysis System to Different Part-Of-Speech Tagset}},
author = {Shunsuke Kozawa, Kiyotaka Uchimoto and Yasuharu Den},
journal = {Journal of Natural Language Processing},
year = {2014},
doi = {10.5715/jnlp.21.379},
url = {https://doi.org/10.5715/jnlp.21.379}
}References
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