tailieunhanh - Báo cáo khoa học: "A Symbolic Approach to Near-Deterministic Surface Realisation using Tree Adjoining Grammar"

Surface realisers divide into those used in generation (NLG geared realisers) and those mirroring the parsing process (Reversible realisers). While the first rely on grammars not easily usable for parsing, it is unclear how the second type of realisers could be parameterised to yield from among the set of possible paraphrases, the paraphrase appropriate to a given generation context. In this paper, we present a surface realiser which combines a reversible grammar (used for parsing and doing semantic construction) with a symbolic means of selecting paraphrases. . | A Symbolic Approach to Near-Deterministic Surface Realisation using Tree Adjoining Grammar Claire Gardent CNRS LORIA Nancy France Eric Kow INRIA LORIA UHP Nancy France Abstract Surface realisers divide into those used in generation NLG geared realisers and those mirroring the parsing process Reversible re-alisers . While the first rely on grammars not easily usable for parsing it is unclear how the second type of realisers could be parameterised to yield from among the set of possible paraphrases the paraphrase appropriate to a given generation context. In this paper we present a surface realiser which combines a reversible grammar used for parsing and doing semantic construction with a symbolic means of selecting paraphrases. 1 Introduction In generation the surface realisation task consists in mapping a semantic representation into a grammatical sentence. Depending on their use on their degree of nondeterminism and on the type of grammar they assume existing surface realisers can be divided into two main categories namely NLG Natural Language Generation geared realisers and reversible realisers. NLG geared realisers are meant as modules in a full-blown generation system and as such they are constrained to be deterministic a generation system must output exactly one text no less no more. In order to ensure this determinism NLG geared realisers generally rely on theories of grammar which systematically link form to function such as systemic functional grammar SFG Matthiessen and Bateman 1991 and to a lesser extent Meaning Text 328 Theory MTT Mel cuk 1988 . In these theories a sentence is associated not just with a semantic representation but with a semantic representation enriched with additional syntactic pragmatic and or discourse information. This additional information is then used to constrain the realiser One drawback of these NLG geared realisers however is that the grammar used is not usually reversible .