tailieunhanh - Báo cáo khoa học: "Formal Constraints on Metarules"

Metagrammaticai formalisms that combine context-free phrase structure rules and metarules (MPS grammars) allow concise statement of generalizations about the syntax of natural languages. Unconstrained MPS grammars, tmfortunately, are not cornputationally "safe." We evaluate several proposals for constraining them, basing our amae~ment on computational tractability and explanatory adequacy. We show that none of them satisfies both criteria, and suggest new directions for research on alternative metagrammatical formalisms. . | Formal Constraints on Metarules Stuart M. Shieber Susan u. Stucky Hans Uszkoreit and Jane J. Robinson SRI International 333 Ravenswood Avenue Menlo Park California Abstract Metagrammatical formalisms that combine context-free phrase structure rules and metarules MPS grammars allow concise statement of generalizations about the syntax of natural languages. Unconstrained MPS grammars unfortunately are not computationally safe. We evaluate several proposals for constraining them basing our assessment on computational tractability and explanatory adequacy. We show that none of them satisfies both criteria and suggest new dữections for research on alternative metagrammatical formalisms. 1. Introduction The computational-linguistics community has recently shown interest in a variety of metagrammatical formalisms for encoding grammars of natural language. A common technique found in these formalisms involves the notion of a metarule which in its most common conception is a device used to generate grammar rules from other given grammar A metarule is essentially a statement declaring that if a grammar contains rules that match one specified pattern it also contains rules that match some other specified pattern. For example the following metarule 1 VP V VP VP V ADVP VP aux states that if there is a rule that expands a finite VP into a finite auxiliary and a nonfinite VP there will also be a rule that expands the VP as before except for an additional adverb between the auxiliary and the nonfinite The patterns may contain variables in which case they characterize families of related rules rather than individual pairs. This research was supported by Che National Science Foundation grant No. IST-8103S50. The views and conclusions expressed in this document are those or the authors and should not be interpreted as representative of the views of the National Science Foundation or the United States government. We are indebted to Fernando Pereira Stanley Peters and .

• Báo cáo khoa học
• Formal Constraints on Metarules
• Stuart M
• Shieber
• Susan U
• Stucky
• 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
• INTERFACES TO DATA BASE SYSTEMS
• 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
• DATABASES THEORETICAL
• TECHNICAL ISSUES
• TRANSPORTABLE NATURAL LANGUAGE INTERFACES
• PROBLEMS AND TECHNIQUES
• Barbara J
• Grosz
• THEORETICAL TECHNICAL ISSUES
• NATURAL LANGUAGE ACCESS TO DATABASES
• R
• Petrick
• Domain Independent
• Database Access Systems
• ISSUES IN NATURAL LANGUAGE
• ACCESS TO DATABASES
• A LOGIC PROGRAMMING PERSPECTIVE
• Sharon C
• Salveter David Maier
• PLANNING NATURAL LANGUAGE
• EXPRESSIONS REFERRING
• Douglas E
• Appelt
• THE TEXT SYSTEM
• NATURAL LANGUAGE GENERATION
• Kathleen R
• M
• MENTING A DATABASE
• KNOWLEDGE REPRESENTATION
• THE KEY TO THE SELECTION PROBLEM
• E
• Jeffrey Conklin David D
• McDonald
• A KNOWLEDGE ENGINEERING
• NATURAL LANGUAGE UNDERSTANDING
• Stuart C
• Shapiro
• NATURAL LANGUAGE TEXTS
• NECESSARILY GRAMMATICAL
• EVEN COMPLETE
• UNGRAMHATICALITY
• EXTRA GRAMMATICALITY
• NATURAL LANGUAGE UNDERSTANDING SYSTEMS
• Taxonomy
• Descriptions
• Individuals in Natural
• Language Understanding
• The Use of Ooject Special Knowledge
• Natural Language Processing
• Mark H
• Bursteln