Unknown word extraction for Chinese documents

  • Authors:
  • Keh-Jiann Chen;Wei-Yun Ma

  • Affiliations:
  • Institute of Information Science, Academia Sinica;Institute of Information science, Academia Sinica

  • Venue:
  • COLING '02 Proceedings of the 19th international conference on Computational linguistics - Volume 1
  • Year:
  • 2002

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Abstract

There is no blank to mark word boundaries in Chinese text. As a result, identifying words is difficult, because of segmentation ambiguities and occurrences of unknown words. Conventionally unknown words were extracted by statistical methods because statistical methods are simple and efficient. However the statistical methods without using linguistic knowledge suffer the drawbacks of low precision and low recall, since character strings with statistical significance might be phrases or partial phrases instead of words and low frequency new words are hardly identifiable by statistical methods. In addition to statistical information, we try to use as much information as possible, such as morphology, syntax, semantics, and world knowledge. The identification system fully utilizes the context and content information of unknown words in the steps of detection process, extraction process, and verification process. A practical unknown word extraction system was implemented which online identifies new words, including low frequency new words, with high precision and high recall rates.