Analysis Grammar of Japanese in the Mu-project - A Procedural Approach to Analysis Grammar

Analysts Grammar or Japanese tn the Nu-ProJect - A Procedural Approach to Analysts Grammar - Jun-tcht TSUJII. Jun-tcht NAKANURA and Nakoto NAGAO Department of Electrical Engineering Kyoto University Kyoto. JAPAN Abstract Analysts grammar of Japanese tn the Mu-proJect ts presented, It is emphasized that rules expressing constraints on stngle linguistic structures and rules for selecting the most preferable readtngs are completely different In nature, and that rules for selecting preferale readings should be utilized tn analysts grammars of practical HT systems. It ts also clatmed that procedural control ts essential tn integrating such rules tnto a unified grammar. Some sample rules are gtven to make the points of discussion clear and concrete. 1. Introduction The Hu-ProJect ts a Japanese nattonal project supported by grants from the Special Coordination Funds for Promoting Science & Technology of STA(Sctence and Technology Agency). whlch atms to develop Japanese-English and English-Japanese machine translation systems. Ve currently restrict the domain of translation to abstracts of scientific and technological papers. The systems are based on the transfer approach[;], and consist of three phases: analysts, transfer and generation. In thts paper, we focus on the analysts grammar of Japanese tn the Japanese-English system. The grammar has been developed by using GRADE which ts a programming language specially designed for thts project[2]. The grammar now consists of about 900 GRADE rules. The experiments so far show that the grammar works very well and ts comprehensive enough to treat various linguistic phenomena tn abstracts. In thts paper we wtll discuss some of the basic design principles of the grammar together wtth its detatled construction. Some examples of grammar rules and analysts results wtll be shown to make the points of our discussion clear and concrete. 2. Procedural Grammar There has been a prominent tendency tn recent computational linguistics to re-evaluate CFG and use tt dtrectly or augment tt to analyze sentences[3.4.5]. In these systems(frameworks), CFG rules Independently describe constraints on stngle linguistic structures, and a universal rule application mechanism automatically produces a set of posstble structures which satisfy the given constraints. It ts well-known, however, that such sets of posstble structures often become unmanageably large. Because two separate rules such as NP ..... • NP PREP-P VP ..... • VP PREP-P are usually prepared tn CFG grammars tn order to analyze noun and verb phrases modifted by prepositional phrases. CFG grammars provide two syntactic analyses for She was given flowers by her uncle. Furthermore. the ambiguity of the sentence ts doubled by the lexlcal ambiguity of "by". which can be read as etther a locattve or an agenttve preposition. Since the two syntactic structures are recognized by compZetely independent ru]es and the semantic interpretations of "by" are given by independent processes tn the ]ater stages. It ts difficult to compare these four readings during the anaZysts to gtve a preference to one of these four readings. A rule such as "If a sentence ts passlve and there ts a "by"-prepostttonal phrase, tt ts often the case that the prepositional phrase …

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