Showing papers on "Rule-based machine translation published in 1979"
Dissertation•
01 Jun 1979
TL;DR: The focussing mechanism is designed to take advantage of syntactic and semantic information encoded as constraints on the choice of anaphora interpretation, and provides a principled means for choosing when to apply the constraints in the comprehension process.
Abstract: : This report investigates the process of focussing as a description and explanation of the comprehension of certain anaphoric expressions in English discourse. The investigation centers on the interpretation of definite anaphora, that is, on the personal pronouns, and noun phrases used with a definite article the, this, or that. Focussing is formalized as a process in which a speaker centers attention on a particular aspect of the discourse. An algorithmic description specifies what the speaker can focus on and how the speaker may change the focus of the discourse as the discourse unfolds. The algorithm allows for a simple focussing mechanism to be constructed: an element in focus, an ordered collection of alternate foci, and a stack of old foci. The data structure for the element in focus is a representation which encodes a limited set of associations between it and other elements from the discourse as well as from general knowledge. This report also establishes other constraints which are needed for the successful comprehension of anaphoric expressions. The focussing mechanism is designed to take advantage of syntactic and semantic information encoded as constraints on the choice of anaphora interpretation. These constraints are due to the work of language researchers; and the focussing mechanism provides a principled means for choosing when to apply the constraints in the comprehension process.
347 citations
01 Jun 1979
TL;DR: This approach attempts to develop a general method for shape recognition by using both semantic and syntactic information, namely, the attributes and production rules.
Abstract: The syntactic method is used to describe the structure of a two-dimensional shape by grammatical rules and the local details by primitives. Four attributes are proposed to describe an open curve segment, and the angle between two consecutive curve segments is used to describe the connection. The properties of the attributes and the recognition capability are studied. Two algorithms are implemented to perform the primitive extraction and syntax analysis at the same step by using both semantic and syntactic information, namely, the attributes and production rules. Also, an automatic inference procedure for the shape grammar is presented. This approach attempts to develop a general method for shape recognition.
134 citations
TL;DR: This paper describes a parser whose input is a piecewise linear encoding of a contour and whose output is a string of high-level descriptions: arcs, corners, protrusions, intrusions, etc.
Abstract: In many cases a picture is described in terms of various plane objects and their shape. This paper describes a parser whose input is a piecewise linear encoding of a contour and whose output is a string of high-level descriptions: arcs, corners, protrusions, intrusions, etc. Such a representation can be used not only for description but also for recognition. Previous syntactic techniques for contour description have often used high-level languages for the description of contours. This has been necessary in order to guarantee contour closure and eliminate the noise. In the present approach the numerical preprocessing of the contour removes most of the noise and also produces the answers to certain simple questions about its shape. Therefore, simpler grammars can be used for the contour description. Examples of descriptions of contours are given for handwritten numerals, white blood cells, and printed wiring circuit boards.
119 citations
101 citations
29 Jun 1979
66 citations
01 Jan 1979
TL;DR: This paper presents techniques for automatically generating interpreters from equations, analagous to well-known techniques for generating parsers from context-free grammars, and believes that the techniques form the beginnings of a useful discipline of interpreting, comparable to the existing discipline of parsing.
Abstract: Equations provide a rich, intuitively understandable notation for describing nonprocedural computing languages such as LISP and Lucid. In this paper, we present techniques for automatically generating interpreters from equations, analagous to well-known techniques for generating parsers from context-free grammars. The interpreters so generated are exactly faithful to the simple traditional mathematical meaning of the equations-no lattice-theoretic or fixpoint ideas are needed to explain the correspondence. The main technical problem involved is the extension of efficient practical string matching algorithms to trees. We present some new efficient table-driven matching techniques for a large class of trees, and point out unsolved problems in extending this class. We believe that the techniques of this paper form the beginnings of a useful discipline of interpreting, comparable to the existing discipline of parsing.
29 citations
TL;DR: A syntactic-semantic approach to information extraction from images is described, which involves the injection of semantic considerations into context-free grammars that carry the numerical, the structural, and the a prior real world knowledge about the pattern the authors want to extract.
Abstract: A syntactic-semantic approach to information extraction from images is described. The methodology involves the injection of semantic considerations into context-free grammars. The semantic considerations include feature vectors, selection restrictions, feature transfer functions, semantic well-formedness, etc. With such injection, we can make a description scheme which carries the numerical, the structural, and the a prior real world knowledge about the pattern we want to extract. From the description we can construct an analytical mechanism, the creation machine, which wil find the desired pattern amid a chaos of noisy primitives.
26 citations
01 Aug 1979
TL;DR: Attribute grammars have proved useful as the basis of input languages for compiler-compilers and many algorithms have evolved which can be used to automatically produce an evaluator for a given attribute grammar.
Abstract: Attribute grammars [14] have proved useful as the basis of input languages for compiler-compilers. Many algorithms have evolved which can be used to automatically produce an evaluator for a given attribute grammar. The task of an evaluator is to compute the values of the attribute instances attached to a parse tree. From the compiler point of view, the evaluator takes care of the semantic analysis and in some cases also the code generation of the compiler. An overview of various evaluation algorithms is given in [6]. A bibliography can be found in [21].
22 citations
TL;DR: This paper argues that the knowledge of such rules should be viewed as a part of the speaker's linguistic competence, and surveys the various types of rules necessary in a genre theory, examines the problems of their formulation in the framework of a semantically based transformational text grammar, and offers a discussion of their hermeneutic function.
22 citations
TL;DR: Two noncanonical extensions of the simple LR(1) (SLR(1)) method are presented, which reduce not only handles but also other phrases of sentential forms, to improve the parsing and translation of programming languages.
Abstract: Two noncanonical extensions of the simple LR(1) (SLR(1)) method are presented, which reduce not only handles but also other phrases of sentential forms. A class of context-free grammars called leftmost SLR(1) (LSLR(1)) is defined by using lookahead symbols which appear in leftmost derivations. This class includes the SLR(1), reflected SMSP, and total precedence grammars as proper subclasses. The class of LSLR(1) languages properly includes the deterministic context-free languages, their reflections, and total precedence languages. By requiring that phrases which have been scanned be reduced as early as possible, a larger class of context-free grammars called noncanonical SLR(1) (NSLR(1)) is defined. The NSLR(1) languages can be recognized deterministically in linear time using a two-stack pushdown automaton. An NSLR(1) parser generator has been implemented. Empirical results show that efficient NSLR(1) parsers can be constructed for some non-LR grammars which generate nondeterministic languages. Applications of the NSLR(1) method to improve the parsing and translation of programming languages are discussed.
22 citations
TL;DR: It is concluded that there are at present no compelling theoretical grounds for requiring that transformational grammars enumerate only recursive sets.
Abstract: Many believe that the grammatical sentences of a natural language are a recursive set. In this paper I argue that the commonly adduced grounds for this belief are inconclusive, if not simply unsound. Neither the native speaker's ability to classify sentences nor his ability to comprehend them requires it. Nor is there at present any reason to think that decidability has any bearing on first-language acquisition. I conclude that there are at present no compelling theoretical grounds for requiring that transformational grammars enumerate only recursive sets. Hence, the fact that proposed transformational grammars do not satisfy this requirement does not, as some have claimed, represent a shortcoming in current theory.
29 Oct 1979
TL;DR: It is observed that the same important ideas emerged independently for the automatic analysis and translation of both natural and artificial languages in the 1950s and early 1960s.
Abstract: Origins of the theory of formal languages and automata are surveyed starting from 1936 with the work of Turing and Post. Special attention is given to the machine translation projects of the 1950s and early 1960s and associated work in mathematical linguistics. The development of the Chomsky hierarchy of grammars, machines, and languages from 1956 to 1964 is traced. It is observed that the same important ideas emerged independently for the automatic analysis and translation of both natural and artificial languages. Since 1964, formal language theory is part of theoretical computer science. A few of the directions since 1964 are considered: restrictions and extensions of context-free grammars and pushdown store automata, unifying frameworks, and complexity questions.
TL;DR: It is shown how the formalism can be translated into languages for data definition and data manipulation, of the type associated with data-base systems, and provides a method of incorporating consistency preconditions to structural operations and proving the correctness of the data structures that arise in using such languages.
Abstract: Rooted, labeled, directed graphs (RLDs) are taken as the basis for describing data structures. A constructive formalism is set up to describe RLDs, generate them by means of grammars, and carry out operations such as accessing nodes, inserting and deleting data items, and recognizing graph patterns. It is shown how the formalism can be translated into languages for data definition and data manipulation, of the type associated with data-base systems. The availability of the formalism allows a systematic development of such languages, and provides a method of incorporating consistency preconditions to structural operations and proving the correctness of the data structures that arise in using such languages.
TL;DR: It is proved that a stochastic pushdown transducer can be constructed to define the same translations as a simple schema, and that the simple schema are characterized by stoChastic contextfree grammars and automata.
Abstract: Stochastic syntax-directed translation schemata describe both the syntactic structure and the probability distribution of stochastic mappings between contextfree languages. The relationship between stochastic syntax-directed translation schemata and stochastic grammars and automata are presented by proving that a stochastic pushdown transducer can be constructed to define the same translations as a simple schema, and that the simple schema are characterized by stochastic contextfree grammars. Asymptotic properties of linear schemata are established by the theory of Markov chains. Since stochastic translations contain both input and output strings, their information content can be described. Equations are developed for both the information content and the rate of stochastic translations.
TL;DR: Attribute grammars have proved useful as the basis of input languages for compiler-compilers as discussed by the authors, and many algorithms have evolved which can be used to automatically produce an evaluator for a given a...
Abstract: Attribute grammars [14] have proved useful as the basis of input languages for compiler-compilers. Many algorithms have evolved which can be used to automatically produce an evaluator for a given a...
01 Jan 1979
TL;DR: This paper is to show how some semantic problems are handled in the machine translation system S A L A T (= System for Automatic Language Analysis and Translation)1.
Abstract: This paper is to show how some semantic problems are handled in the machine translation system S A L A T (= System for Automatic Language Analysis and Translation)1. Therefore it will be necessary to give a rather comprehensive introduction into the system. Otherwise the topic could not be treated in a satisfactory way, and it would be impossible for the reader to get a sufficiently detailed and concrete idea of the involved problems and proposed solutions.
03 Sep 1979
TL;DR: An algorithm is developed to decide equivalence of an operator-precedence grammar and the underlying Floyd's operator- Precedence parsing algorithm, a result of possible practical significance.
Abstract: The classes of languages definable by operator-precedence grammars and by Floyd's operator-precedence algorithms are studied. Operator-precedence languages are shown to be a proper superclass of languages accepted by Floyd's operator-precedence parsing algorithms. An algorithm is developed to decide equivalence of an operator-precedence grammar and the underlying Floyd's operator-precedence parsing algorithm, a result of possible practical significance. As a consequence a necessary and sufficient condition for an operator-precedence grammar to be valid grammatical characterization for the underlying Floyd's operator-precedence parsing algorithm is obtained.
TL;DR: It is shown that SVMT-bounded Grammars generate only context free languages, and that all context free grammars can be converted to equivalent SVMT -boundedgrammars.
Abstract: The concept of SVMT-bounded grammars is introduced. It is shown that SVMT-bounded grammars generate only context free languages, and that all context free grammars can be converted to equivalent SVMT-bounded grammars. It is also shown that the property of SVMT-boundedness can sometimes be used to conclude that a given language is context free while certain previous results cannot be used for this purpose.
01 Jan 1979
TL;DR: It is proved that every grammar is topologically equivalent to one in normal form, that the discrete topology can be realizing on every context-free language, and that a language is finite if and only if every topology on it can be realized as one of the topologies proposed by Walter.
Abstract: This paper places the work of H. Walter on classification of grammars and languages via topology in a more general framework and provides short proofs of his main results. Also, it is proved that every grammar is topologically equivalent to one in normal form, that the discrete topology can be realized on every context-free language, and that a language is finite if and only if every topology on it can be realized as one of the topologies proposed by Walter. In addition, a new and straightforward approach is provided to yield the necessary background results, on divisibility and cancellation in categories of derivations, due to D. Benson and G. Hotz.
TL;DR: The ACD, being a collection of algorithms, is based on certain grammars of English and Russian and presupposes some special features of the general and auxiliary algorithms with which that dictionary works.
Abstract: According to the theory of determinants put forward by the present author and described first in , every meaning (translation) of a polysemantic word differing from the most general one (the general procedure of the translation algorithm) is determined in the context by other words with which it forms combinations, or by some grammatical distinguishers. In other words, it is believed that in most cases the differentiation of meanings is possible on the basis of formal characteristics of the word itself and its context; the cases when such differentiation is impossible are rare enough. The ACD, being a collection of algorithms, is based on certain grammars of English and Russian and presupposes some special features of the general and auxiliary algorithms with which that dictionary works. The grammar of English is defined mainly as follows: -all English words have been divided into grammatical classes (corresponding in general to traditional parts of speech: noun, adjective, verb, adverb, preposition, conjunction, punctuation mark; the last is considered as forming a grammatical class because of the role it plays in syntactic analysis-for example, a comma-and besides, a punctuation mark also receives a translation equivalent). In the automatic language processing, pronouns and numerals are divided according to their functions, into subclasses of nouns and adjectives. Figures form a special subclass.4 In the classes of nouns and adjectives, special distributional semantic subclasses are singled out. These consist of nouns: conjunctive (which, who), pronominal (I, he, it), numerals (one, two), nouns of time and duration, geographical names, periodicals, names of organizations
TL;DR: An algorithm for syntactical analysis with linear average cost is developed in this paper and a worst case quadratic upper bound is derived.
Abstract: This paper is concerned with an extension of context-free LL(k) grammars, called RLL(k) grammars. RLL(k) grammars are powerful enough to generate non-context-free languages. In particular context-sensitive constructs of programming languages can be formalized conveniently. RLL(k) grammars have the pleasant property that fast syntactical check procedures exist. An algorithm for syntactical analysis with linear average cost is developed in this paper. A worst case quadratic upper bound is derived.
TL;DR: It is shown that all quasi-realtime one-way multi-counter languages can be generated by a context-free ɛ-free programmed grammar (even under the free interpretation) and can be used to obtain a new and almost trivial proof of the fundamental theorem that arbitrary context- free programmed grammars can generate all recursively enumerable languages.
Abstract: We show that all quasi-realtime one-way multi-counter languages can be generated by a context-free ?-free programmed grammar (even under the free interpretation). The result can be used to obtain a new and almost trivial proof of the fundamental theorem that arbitrary context-free programmed grammars can generate all recursively enumerable languages. The proof of our result also yields the following, interesting characterization: the quasi-realtime one-way multi-counter languages are precisely the ?-limited homomorphic images of (free) context-free programmed production languages. It follows that the (free) derivation languages of context-free or even context-free programmed grammars, which were known to be context-sensitive, are in fact contained in the family of context-free ?-free programmed languages.
01 Apr 1979
TL;DR: A formulation of an abstract model of probabilistic machines that is general enough to encompass all existing types of probablistic machines is presented and includes many of the known results as special cases.
Abstract: In the past several years, there has been an increasing interest in the study of probabilistic machines, grammars, and families of languages associated with these machines and/or grammars. However, until now, the emphasis has been placed on the study of the structures of the particular probabilistic machines, grammars, and/or families of languages. The main objective of the present paper is to develop a general treatment for probabilistic machines and languages. A formulation of an abstract model of probabilistic machines is presented. Various families of random languages associated with this model of probabilistic machines are studied and characterized. Since the model is general enough to encompass all existing types of probabilistic machines, the results obtained in this paper includes many of the known results as special cases. They also provide insights to the underlying structures of probabilistic machines and languages.
01 Jan 1979
TL;DR: In this article, the authors introduce Syntax Directed Translations (SDT) and illustrate its use in a sample translation of ASPLE, a programming language example by Cleaveland and Uzgalis, and advocate a method of designing a translation top-down by means of context-free skeleton translations.
Abstract: Similar to the Attributed Translations of Lewis, Rosenkrantz, and Sterns, pairs of Two-level Grammars (G,G’) may be specified which allow a translation of a word x ∈ L (G) into a word y ∈ L(G’) using the well-known method of Syntax Directed Translations. Here we concentrate on introducing the idea and illustrating its use in a sample translation of ASPLE, a programming language example by Cleaveland and Uzgalis. In addition, we advocate a method of designing such a translation top-down by means of context-free skeleton translations.
01 Jan 1979
TL;DR: This work introduces the idea of pairs of Two-level Grammars (G,G') and advocates a method of designing such a translation top-down by means of context-free skeleton translations.
Abstract: Similar to the Attributed Translations of Lewis, Rosenkrantz, and Sterns, pairs of Two-level Grammars (G,G') may be specified which allow a translation of a word x E L (G) into a word y E L (G') using the well-known method of Syntax Directed Translations. Here we concentrate on introducing the idea and illustrating its use in a sample translation of ASPLE, a programming language example by Cleaveland and Uzgalis. In addition, we advocate a method of designing such a translation top-down by means of context-free skeleton translations.