tailieunhanh - Báo cáo khoa học: "A rich environment for experimentation unification grammars"

The d e v e l o p m e n t of ud arose out of the need to have a v a i l able a full set of p r o t o t y p i n g and development tools for a n u m b e r of different research projects in computational linguistics, all involving extensive text coverage inIn many respects relational abstractions resemble Prolog proc e d u r e s. | A rich environment for experimentation with unification grammars R. Johnson M. Rosner IDSIA Lugano ABSTRACT This paper describes some of the features of a sophisticated language and environment designed for experimentation with unification-oriented linguistic descriptions. The system which is called ud has to date been used successfully as a development and prototyping tool in a research project on the application of situation schemata to the representation of real text and in extensive experimentation in machine translation. While the ud language bears close resemblances to all the well-known unification grammar formalisms it offers a wider range of features than any single alternative plus powerful facilities for notational abstraction which allow users to simulate different theoretical approaches in a natural way. After a brief discussion of the motivation for implementing yet another unification device the main body of the paper is devoted to a description of the most important novel features of ud. The paper concludes with a discussion of some questions of implementation and completeness . 1. Introduction. The development of ud arose out of the need to have available a full set of prototyping and development tools for a number of different research projects in computational linguistics all involving extensive text coverage in several languages principally a demanding machine translation exercise and a substantial investigation into some practical applications of situation semantics Johnson Rosner and Rupp forthcoming . The interaction between users and implementers has figured largely in the development of the system and a major reason for the richness of its language and environment has been the pressure to accommodate the needs of a group of linguists working on three or four languages simultaneously and importing ideas from a variety of different theoretical backgrounds. Historically ud evolved out of a near relative of PATR-II shieber 1984 and its origins