tailieunhanh - Báo cáo khoa học: "A PARSING METHOD OR INFLECTIONAL FREE WORD ORDER LAN"

This paper presents a parser of an inflectional free word order language, namely Finnish. Two-way finite automata are used to specify a functional dependency grammar and to actually parse Finnish sentences. Each automaton gives a functional description of a dependency structure within a constituent. Dynamic local control of the parser is realized by augmenting the automata with simple operations to make the automata, associated with the words of an input sentence, activate one another. | TWO-WAY FINITE AUTOMATA AND DEPENDENCY GRAM4AR A PARSING METHOD EUR INFLECTIONAL EREE WORD ORDER IANGUAGESÌ Esa Nelimarkka Harri Jappinen and Aamo Lehtola Helsinki University of Technology Helsinki Finland ABSTRACT This paper presents a parser of an inflectional free word order language namely Finnish. Two-way finite automata are used to specify a functional dependency grairnar and to actually parse Finnish sentences. Each automaton gives a functional description of a dependency structure within a constituent. Dynamic local control of the parser is realized by augmenting the automata with simple operations to make the automata associated with the words of an input sentence activate one another. I INTRODUCTION This paper introduces a computational model for the description and analysis of an inflectional free word order language namely Finnish. We argue that such a language can be conveniently described in the framework of a functional dependency grammar which uses formally defined syntactic functions to specify dependency structures and deep case relations to introduce semantics into syntax. We show how such a functional grarrtnar can be compactly and efficiently modelled with finite two-way automata which recognize the dependants of a word in various syntactic functions on its both sides and build corresponding dependency structures. The automata along with formal descriptions of the functions define the graimar. The functional structure specifications are augmented with simple control instructions so that the automata associated with the words of an input sentence actually parse the sentence. This gives a strategy of local decisions resulting in a strongly data driven left-to-right and bottom-up parse. A parser based on this model is being implemented as a conponent of a Finnish natural language data base interface where it follows a separate morphological analyzer. Hence throughout the paper vre assume that all relevant morphological and lexical information has