Showing papers on "Formal grammar published in 1986"

SNePS considered as a fully intensional propositional semantic network

Abstract: We present a formal syntax and semantics for SNePS considered as the (modeled) mind of a cognitive agent. The semantics is based on a Meinongian theory of the intensional objects of thought that is appropriate for AI considered as "computational philosophy" or "computational psychology".

Grammatical Inference: Introduction and Survey-Part II

Abstract: Inference of high-dimensional grammars is discussed. Specifically, techniques for inferring tree grammars are briefly presented. The problem of inferring a stochastic grammar to model the behavior of an information source is also introduced and techniques for carrying out the inference process are presented for a class of stochastic finite-state and context-free grammars. The possible practical application of these methods is illustrated by examples.

The Structure of Paintings: Formal Grammar and Design

Abstract: Although substantial literature exists on the properties of formal grammars, much less has been written on the use of grammars for describing the languages which they are capable of explaining. Thus we see a well-developed theory concerning the expressive (generative) power of different kinds of formal grammars and powerful algorithmic methods (analytical) for the languages defined by these grammars. For natural spoken and written languages, grammars have been used for explaining their structure but for the two-dimensional generalization to designs, pictures, images, and fine arts, which has been known since 1964, almost no use has been made of grammars.The purpose of this paper is to call attention to the powerful dormant tools that can be used in the design arts. Some of the benefits of using these tools for describing existing (natural) design languages are discussed. How such uses may direct us from the more formal design arts into the fine arts is discussed by reporting progress on building a grammar...

Semigroups and Languages of Dot-Depth 2

Abstract: This paper is a contribution to the problem of effectively determining the dot-depth of a star-free language, a problem in the theory of automata and formal languages with close connections to algebra and formal logic. We conjecture an effective criterion for determining whether a given language has dot-depth 2. The condition is shown to be necessary in general, and sufficient for languages over a two-letter alphabet. The condition involves a novel use of categories in the study of semigroup-theoretic problems.

Copying in natural languages, context-freeness, and queue grammars

Abstract: The documentation of (unbounded-length) copying and cross-serial constructions in a few languages in the recent literature is usually taken to mean that natural languages are slightly context-sensitive. However, this ignores those copying constructions which, while productive, cannot be easily shown to apply to infinite sublanguages. To allow such finite copying constructions to be taken into account in formal modeling, it is necessary to recognize that natural languages cannot be realistically represented by formal languages of the usual sort. Rather, they must be modeled as families of formal languages or as formal languages with indefinite vocabularies. Once this is done, we see copying as a truly pervasive and fundamental process in human language. Furthermore, the absence of mirror-image constructions in human languages means that it is not enough to extend Context-free Grammars in the direction of context-sensitivity. Instead, a class of grammars must be found which handles (context-sensitive) copying but not (context-free) mirror images. This suggests that human linguistic processes use queues rather than stacks, making imperative the development of a hierarchy of Queue Grammars as a counterweight to the Chomsky Grammars. A simple class of Context-free Queue Grammars is introduced and discussed.

Formal specification of natural language syntax using two-level grammar

Abstract: The two-level grammar is investigated as a notation for giving formal specification of the context-free and context-sensitive aspects of natural language syntax. In this paper, a large class of English declarative sentences, including post-noun-modification by relative clauses, is formalized using a two-level grammar. The principal advantages of two-level grammar are: 1) it is very easy to understand and may be used to give a formal description using a structured form of natural language; 2) it is formal with many well-known mathematical properties; and 3) it is directly implementable by interpretation. The significance of the latter fact is that once we have written a two-level grammar for natural language syntax, we can derive a parser automatically without writing any additional specialized computer programs. Because of the ease with which two-level grammars may express logic and their Turing computability we expect that they will also be very suitable for future extensions to semantics and knowledge representation.

On methods for interface specification and design

Abstract: In this paper we analyse a subsystem, MINICON, of the UNICON interface to the UNIX operating system using two well-known formal methods, Reisner's Formal Grammar and Moran's Command Language Grammar. The contribution each technique is able to make towards a complete specification of interface systems is then identified and discussed.

Linguistic bases for machine translation

Abstract: My aim in organizing this panel is to stimulate the discussion between researchers working on MT and linguists interested in formal syntax and semantics. I am convinced that a closer cooperation will be fruitful for both sides. I will be talking about experimental MT or MT as a research project and not as a development project.[1]

Elements for the Formal Description of Systems

Abstract: This paper is an introductory overview of some key concepts that constitute a theoretical basis for the formal description of systems Following a brief discussion of the criteria determining the usefulness of such concepts for system analysis and design, this overview addresses formal languages and automata, language semantics (with illustrations in trace theory and formal logic), abstract data types and functional formalisms For what concerns the latter topic, special attention is given to the transformational style of reasoning and to the suitability for describing various kinds of systems A more complete treatment of the functional approach and its applications is given in two companion papers

A Formal Grammar Approach to Human Factors Research

Abstract: Formal grammars and languages are construcled La describe the actions that human subjects must take in using an interactive system for non-programmers. The interactive system has been constructed for experimentation in attempt to determine some guidelines for system design for maximum productivity. Examination of the formal languages suggest that a form of written documentation will be superior to the online documentation provided to some subjects, that a compact presentation of information by the system will be more difficult for the users to deal with, and that providing users a means of anticipating system questions and answering ahead will not make them any more productive. Results from two separate experiments support these hypotheses.

A non-cognitive formal approach to knowledge representation in artificial intelligence

Abstract: With the entry of Artificial Intelligence (AI) into real-time applications, a rigorous analysis of AI expert systems, is required in order to validate them for operational use. To satisfy this requirement for analysis of the associated knowledge representations, the techniques of formal language theory are used. A combination of theorems, proofs and problem-solving techniques from formal language theory are employed to analyze language equivalents of the more commonly used AI knowledge representations of production rules (excluding working memory or situation data) and semantic networks. Using formal language characteristics, it is shown that no single support-tool or automatic-programming tool can ever be constructed that can handle all possible production-rule or semantic-network variations. Additionally, it is shown that the entire set of finite production-rule languages is able to be stored in and retrieved from finite semantic-network languages. In effect, the semantic-network structure is shown to be a viable candidate for a centralized database of knowledge.

The balance between accuracy and fluency. The communicative approach. The concepts of language functions and notions. New technologies and basic needs

Abstract: This chapter discusses the balance between accuracy and fluency. Scholars using various concepts for accuracy and fluency in language learning have stressed and given evidence of the contrast, and sometimes even the conflict, between accuracy and fluency. Accuracy is associated with those traditional methods that are norm-oriented and based on learning formal grammar. This applies to the grammar-translation method and also to the pattern-drill method under which the structures are learnt in a fixed order, from the least to the most difficult ones. To a certain extent, this norm-orientation and formality with a focus on accuracy prevailed throughout the 1960s, despite the fact that language teaching became audio–lingual with more access to real-life situations. One of the most rewarding results of the shift in emphasis to communicative teaching in the 1970s was the functional/notional approach to language learning that was based on the assumption that communication can be regarded as a set of functions and notions that can be practiced at various levels.