8 resultados para Formal language

em Aston University Research Archive


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This study aimed firstly to investigate current patterns of language use amongst young bilinguals in Birmingham and secondly to examine the relationship between this language use and educational achievement. The research then focussed on various practices, customs and attitudes which would favour the attrition or survival of minority languages in the British situation. The data necessary to address this question was provided by a sample of three hundred and seventy-four 16-19 year olds, studying in Birmingham schools and colleges during the period 1987-1990 and drawn from the main linguistic minority communities in Birmingham. The research methods chosen were both quantitative and qualitative. The study found evidence of ethnolinguistic vitality amongst many of the linguistic minority communities in Birmingham: a number of practices and a range of attitudes indicate that linguistic diversity may continue and that a stable diglossic situation may develop in some instances, particularly where demographical and religious factors lead to closeness of association. Where language attrition is occurring it is often because of the move from a less prestigious minority language or dialect to a more prestigious minority language in addition to pressures from English. The educational experience of the sample indicates that literacy and formal language study are of key importance if personal bilingualism is to be experienced as an asset; high levels of oral proficiency in the L1 and L2 do not, on their own, necessarily correlate with positive educational benefit. The intervening variable associated with educational achievement appears to be the formal language learning process and literacy. A number of attitudes and practices, including the very close associations maintained with some of the countries of origin of the families, were seen to aid or hinder first language maintenance and second language acquisition.

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Conventional structured methods of software engineering are often based on the use of functional decomposition coupled with the Waterfall development process model. This approach is argued to be inadequate for coping with the evolutionary nature of large software systems. Alternative development paradigms, including the operational paradigm and the transformational paradigm, have been proposed to address the inadequacies of this conventional view of software developement, and these are reviewed. JSD is presented as an example of an operational approach to software engineering, and is contrasted with other well documented examples. The thesis shows how aspects of JSD can be characterised with reference to formal language theory and automata theory. In particular, it is noted that Jackson structure diagrams are equivalent to regular expressions and can be thought of as specifying corresponding finite automata. The thesis discusses the automatic transformation of structure diagrams into finite automata using an algorithm adapted from compiler theory, and then extends the technique to deal with areas of JSD which are not strictly formalisable in terms of regular languages. In particular, an elegant and novel method for dealing with so called recognition (or parsing) difficulties is described,. Various applications of the extended technique are described. They include a new method of automatically implementing the dismemberment transformation; an efficient way of implementing inversion in languages lacking a goto-statement; and a new in-the-large implementation strategy.

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A major application of computers has been to control physical processes in which the computer is embedded within some large physical process and is required to control concurrent physical processes. The main difficulty with these systems is their event-driven characteristics, which complicate their modelling and analysis. Although a number of researchers in the process system community have approached the problems of modelling and analysis of such systems, there is still a lack of standardised software development formalisms for the system (controller) development, particular at early stage of the system design cycle. This research forms part of a larger research programme which is concerned with the development of real-time process-control systems in which software is used to control concurrent physical processes. The general objective of the research in this thesis is to investigate the use of formal techniques in the analysis of such systems at their early stages of development, with a particular bias towards an application to high speed machinery. Specifically, the research aims to generate a standardised software development formalism for real-time process-control systems, particularly for software controller synthesis. In this research, a graphical modelling formalism called Sequential Function Chart (SFC), a variant of Grafcet, is examined. SFC, which is defined in the international standard IEC1131 as a graphical description language, has been used widely in industry and has achieved an acceptable level of maturity and acceptance. A comparative study between SFC and Petri nets is presented in this thesis. To overcome identified inaccuracies in the SFC, a formal definition of the firing rules for SFC is given. To provide a framework in which SFC models can be analysed formally, an extended time-related Petri net model for SFC is proposed and the transformation method is defined. The SFC notation lacks a systematic way of synthesising system models from the real world systems. Thus a standardised approach to the development of real-time process control systems is required such that the system (software) functional requirements can be identified, captured, analysed. A rule-based approach and a method called system behaviour driven method (SBDM) are proposed as a development formalism for real-time process-control systems.

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The present investigation is based on a linguistic analysis of the 'Housing Act 1980' and attempts to examine the role of qualifications in the structuring of the legislative statement. The introductory chapter isolates legislative writing as a "sub-variety “of legal language and provides an overview of the controversies surrounding the way it is written and the problems it poses to its readers. Chapter two emphasizes the limitations of the available work on the description of language-varieties for the analysis of legislative writing and outlines the approach adopted for the present analysis. This chapter also gives some idea of the information-structuring of legislative provisions and establishes qualification as a key element in their textualisation. The next three chapters offer a detailed account of the ten major qualification-types identified in the corpus, concentrating on the surface form they take, the features of legislative statements they textualize and the syntactic positions to which they are generally assigned in the statement of legislative provisions. The emerging hypotheses in these chapters have often been verified through a specialist reaction from a Parliamentary Counsel, largely responsible for the writing of the ‘Housing Act 1980’• The findings suggest useful correlations between a number of qualificational initiators and the various aspects of the legislative statement. They also reveal that many of these qualifications typically occur in those clause-medial syntactic positions which are sparingly used in other specialist discourse, thus creating syntactic discontinuity in the legislative sentence. Such syntactic discontinuities, on the evidence from psycholinguistic experiments reported in chapter six, create special problems in the processing and comprehension of legislative statements. The final chapter converts the main linguistic findings into a series of pedagogical generalizations, offers indications of how this may be applied in EALP situations and concludes with other considerations of possible applications.

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This study is concerned with one of the most interesting and the least well-researched areas in contemporary research on classroom interaction: that of the discourse variability exhibited by participants. It investigates the way in which the language of native speakers (NSs) as well as that of non-native speakers (NNSs) may vary according to the circumstances under which it is produced. The study, therefore, attempts to characterise the performance of both NSs and NNSs (with particular emphasis placed on the latter) in various types of interaction in and beyond the EFL classroom. These are: Formal Interview (FI), Formal Classroom Interaction (FCI), Informal Classroom Interaction (ICI), Informal Classroom Discussion (ICD), and Informal Conversation (IC). The corpus of the study consisted of four NSs and fifteen NNSs. Both a video and a tape recording was made for each type of interaction, with the exception of the IC which was only audio-recorded so as not to inhibit the natural use of language. Each lasted for 35 minutes. The findings of the study mark clearly the distinction between the `artificiality' of classroom interaction and the `naturalness' or `authenticity' of non-classroom discourse. Amongst the most interesting findings are the following: Unlike both FCI and ICI, in the FI, ICD, and IC, the language of NNSs was characterised by: greater quantity of oral output, a wider range of errors, the use of natural discourse strategies such as holding the floor and self-correction, and a greater number of initiations in both ICD and IC. It is suggested that if `natural' or `authentic' discourse is to be promoted, the incorporation of FI, ICD, and IC into the EFL classroom activities is much needed. The study differs from most studies on classroom interaction in that it attempts to relate work in the EFL classroom to the `real' world as its prime objective.

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Semantic Web Service, one of the most significant research areas within the Semantic Web vision, has attracted increasing attention from both the research community and industry. The Web Service Modelling Ontology (WSMO) has been proposed as an enabling framework for the total/partial automation of the tasks (e.g., discovery, selection, composition, mediation, execution, monitoring, etc.) involved in both intra- and inter-enterprise integration of Web services. To support the standardisation and tool support of WSMO, a formal model of the language is highly desirable. As several variants of WSMO have been proposed by the WSMO community, which are still under development, the syntax and semantics of WSMO should be formally defined to facilitate easy reuse and future development. In this paper, we present a formal Object-Z formal model of WSMO, where different aspects of the language have been precisely defined within one unified framework. This model not only provides a formal unambiguous model which can be used to develop tools and facilitate future development, but as demonstrated in this paper, can be used to identify and eliminate errors present in existing documentation.

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Self-adaptive systems have the capability to autonomously modify their behavior at run-time in response to changes in their environment. Self-adaptation is particularly necessary for applications that must run continuously, even under adverse conditions and changing requirements; sample domains include automotive systems, telecommunications, and environmental monitoring systems. While a few techniques have been developed to support the monitoring and analysis of requirements for adaptive systems, limited attention has been paid to the actual creation and specification of requirements of self-adaptive systems. As a result, self-adaptivity is often constructed in an ad-hoc manner. In order to support the rigorous specification of adaptive systems requirements, this paper introduces RELAX, a new requirements language for self-adaptive systems that explicitly addresses uncertainty inherent in adaptive systems. We present the formal semantics for RELAX in terms of fuzzy logic, thus enabling a rigorous treatment of requirements that include uncertainty. RELAX enables developers to identify uncertainty in the requirements, thereby facilitating the design of systems that are, by definition, more flexible and amenable to adaptation in a systematic fashion. We illustrate the use of RELAX on smart home applications, including an adaptive assisted living system.

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Formulating complex queries is hard, especially when users cannot understand all the data structures of multiple complex knowledge bases. We see a gap between simplistic but user friendly tools and formal query languages. Building on an example comparison search, we propose an approach in which reusable search components take an intermediary role between the user interface and formal query languages.