SAGE - a Sentence Parsing and Generation System

SAGE : a Sentence Parsing and Generation System Jean-Marie Lancel, Miyo Otani, Nathalie Shnonin Usp Sogeti Innoestion 118 rue de Tocque~ille, 75017 Pads, France E-mail: lancelOcsinn.uucp, otaniOc~inn.uucp, ~imon~tOcsin~t.eu~p Laurence Danlos LADL - UNRS Tour Ueatrale, Uni~er~itg Pads VII, ,[ piac~ Ju~i~u, 75005 Pariz, France Abstracts: SAG~ (Sentence Analysis and GEneration system) is an operational parsing and generating system. It is used as a Natural Language Frontend for Esprit project Eeteam-316, whose purpose is to advise a novice user through a cooperative dialogue. The aim of our system is to validate the use of a Lexice)n-Grammar (drawn from the LADL studies) ior sentence-parsing and generation, and to imple~ ~aent )~nguistic knowledge in a declarative way u~- ing a formMism based upon Functional Descrip- tions (FD). We have ales devvloped the parser and the g~ueratio~ module so that they share informa~ tion~ and knowledge bases as much as possible: they work on the same semazLtic dictionary and the same linguistic knowledge bases, except th~ they kave their own graznmar. We have also ires p|emented a tracking of semantic objects that have been f~istantiated during a dialogue session: the so- called Token History is provided for semantic ref- vrence and anaphor resolution during parsing and for pronoun production during generation. After introducing to Esteam-316, this paper de- ,cribelJ the ~nguistic knowledge bases required by SAGE, and then foctmes on the Generation Mod- nleo Sv.ctlon 4 explains how pronouns are handled. The last section is a brief evaluation of our present WO1"k o :t ~introduction to the appli- catioli of SAGE _ ne pro'sing and generating system described here ~ used as a Natural Language Frontend for F~., prlt project Esteam-316, which is an Advice-Gi~ ring system [Decitre 871 [Bruffaerts 86]0 A coopera- tive interactive Man-Machine Interface carries out dialogue functionalities such as recognition of user queries, explanation of domaln~concepts, explana- tion of solutions proposed by the Problem Solver, etc. To describe it briefly, this Dialogue Manager handles the pragmatic level of a dialogue, wherea~ the Natural Language Frontend SAGE deals with linguistic inferences° The chosen l~guage is }~n- glish. The Dialogue Manager and SAGS ~h~re the same lemantic objects, using a formalism b~ed upon Functional Descriptions (FD~) [Kay 81]. The Parser of SAGE extracts the met~uing of the user's query mad represents it with nested FDs. Ox~ the other hand, the Dialogue Manager sends the Generator FDs which describe the semantic conte, nts of the answer. Our previous work [Lancel 86] was based on a uni- que dictionary and a granunar shared by both a parser and a generation module. The grammar formalism required the mixing of syntactic and se- mantic informations in the same structure, which implied the complete rewriting of grautmar when changing from one application domain to another. It could not handle transformational processes such as interrogative and imperative transformations° The system presented here fulfills the four follow- ing requirements: 1. definition of linguistic knowledge bases quit° able for both parsing and generation; 2. integration of lexicon-grammar theory into the …

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