TAILIEUCHUNG - Báo cáo khoa học: "POS Disambiguation and Unknown Word Guessing with Decision Trees"

This paper presents a decision-tree approach to the problems of part-ofspeech disambiguation and unknown word guessing as they appear in Modem Greek, a highly inflectional language. The learning procedure is tag-set independent and reflects the linguistic reasoning on the specific problems. The decision trees induced are combined with a highcoverage lexicon to form a tagger that achieves 93,5% overall disambiguation accuracy. | Proceedings of EACL 99 POS Disambiguation and Unknown Word Guessing with Decision Trees Giorgos s. Orphanos Computer Engineering Informatics Dept and Computer Technology Institute University of Patras 26500 Rion Patras Greece georfan@ Abstract This paper presents a decision-tree approach to the problems of part-of-speech disambiguation and unknown word guessing as they appear in Modem Greek a highly inflectional language. The learning procedure is tag-set independent and reflects the linguistic reasoning on the specific problems. The decision frees induced are combined with a high-coverage lexicon to form a tagger that achieves 93 5 overall disambiguation accuracy. 1 Introduction Part-of-speech POS taggers are software devices that aim to assign unambiguous morphosyntactic tags to words of electronic texts. Although the hardest part of the tagging process is performed by a computational lexicon a POS tagger cannot solely consist of a lexicon due to i morphosyntactic ambiguity . love as verb or noun and ii the existence of unknown words . proper nouns place names compounds etc. . When the lexicon can assure high coverage unknown word guessing can be viewed as a decision taken upon the POS of open-class words . Noun Verb Adjective Adverb or Participle . Towards the disambiguation of POS tags two main approaches have been followed. On one hand according to the linguistic approach experts encode handcrafted rules or constraints based on abstractions derived from language paradigms usually with the aid of corpora Green and Rubin 1971 Voutilainen 1995 . On the other hand according to the data-driven Dimitris N. Christodoulakis Computer Engineering Informatics Dept and Computer Technology Institute University of Patras 26500 Rion Patras Greece dxri@ approach a frequency-based language model is acquired from corpora and has the forms of ngrams Church 1988 Cutting et al. 1992 rules Kindle 1989 Brill 1995 decision frees Cardie 1994 Daelemans et al. 1996

• Báo cáo khoa học
• POS Disambiguation
• Unknown Word Guessing
• Decision Trees
• scientific reports
• model language
• process natural language
• Dialog Control
• Natural Language System
• Dialog Control in a Natural Language System
• Expanding the Horizons
• Natural Language Interfaces
• Phil Hayes
• PROSPECTS OR PRACTICAL
• NATURAL LANGUAGE SYSTEMS
• Workshops
• NATURAL LANGUAGE
• INTERACTION WITH MACHINES
• Long Papers
• COMPUTER INTEBFACE DESIGN MURRAY TUROFF DEPARTMENT OF COMPUTER
• IiVFORMATION SCIENCE IIEW JERSEY INSTITUTE OF TECHNOLOGY
• EVALUATION OF NATURAL LANGUAGE
• INTERFACES TO DATABASE SYSTEMS
• A PANEL DISCUSSION
• database query system
• J
• Norwood Crout
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• Bozena Henisz
• INTERPRETING NATURAL LANGUAGE
• DATABASE UPDATES
• S
• Jermld Kaplan Jim David
• TRANSPORTABLE NATURAL LANGUAGE
• INTERFACES TO DATABASES
• Gary G
• Hendrlx and William H
• Lewis
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• PROBLEMS AND TECHNIQUES
• Barbara J
• Grosz
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• NATURAL LANGUAGE ACCESS TO DATABASES
• R
• Petrick
• Domain Independent
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• A LOGIC PROGRAMMING PERSPECTIVE
• Sharon C
• Salveter David Maier
• PLANNING NATURAL LANGUAGE
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• Douglas E
• Appelt
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• Kathleen R
• M
• MENTING A DATABASE
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• THE KEY TO THE SELECTION PROBLEM
• E
• Jeffrey Conklin David D
• McDonald
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• Stuart C
• Shapiro
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• EVEN COMPLETE
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• Mark H
• Bursteln