tailieunhanh - Báo cáo khoa học: "Generating referring expressions with a unification grammar"

A simple formalism is proposed to represent the contexts in which pronouns, definite/indefinite descriptions, and ordinal descriptions (. 'the second book') can be used, and the way in which these expressions change the context. It is shown that referring expressions can be generated by a unification grammar provided that some phrase-structure rules are specially tailored to express entities in the current knowledge base. | Proceedings of EACL 99 Generating referring expressions with a unification grammar Richard Power Information Technology Research Institute University of Brighton Lewes Road Brighton BN2 4AT UK Abstract A simple formalism is proposed to represent the contexts in which pronouns def-inite indefinite descriptions and ordinal descriptions . the second book can be used and the way in which these expressions change the context. It is shown that referring expressions can be generated by a unification grammar provided that some phrase-structure rules are specially tailored to express entities in the current knowledge base. 1 Introduction Nominal referring expressions are exceptionally sensitive to linguistic context. If a discourse mentions a book potential referring expressions include it a book the book another book the second book along with an unlimited number of more complex descriptions . the red book that mention the book s properties. The choice among these alternatives depends on features of the preceding text whether the referent has been mentioned before whether it is currently a focus of attention whether different referents of the same type . other books have been introduced as well. Taking account of such factors poses a tricky problem for Natural Language Generation nlg especially in applications in which efficiency . fast generation of texts is a priority. This paper proposes a method that allows efficient generation of referring expressions through a unification grammar at the cost of some initial effort in tailoring the phrase-structure rules to the current knowledge base. The method was invented to meet the needs of applications using WYSIWYM editing Power and Scott 1998 which allow an author to control the content of an automatically generated text without prior training in knowledge engineering. WYSIWYM is based Figure 1 Network representation of an instruction on the idea of a feedback text . a text .