974 resultados para Formal language


Relevância:

60.00% 60.00%

Publicador:

Resumo:

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.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Modern software systems are often large and complicated. To better understand, develop, and manage large software systems, researchers have studied software architectures that provide the top level overall structural design of software systems for the last decade. One major research focus on software architectures is formal architecture description languages, but most existing research focuses primarily on the descriptive capability and puts less emphasis on software architecture design methods and formal analysis techniques, which are necessary to develop correct software architecture design. ^ Refinement is a general approach of adding details to a software design. A formal refinement method can further ensure certain design properties. This dissertation proposes refinement methods, including a set of formal refinement patterns and complementary verification techniques, for software architecture design using Software Architecture Model (SAM), which was developed at Florida International University. First, a general guideline for software architecture design in SAM is proposed. Second, specification construction through property-preserving refinement patterns is discussed. The refinement patterns are categorized into connector refinement, component refinement and high-level Petri nets refinement. These three levels of refinement patterns are applicable to overall system interaction, architectural components, and underlying formal language, respectively. Third, verification after modeling as a complementary technique to specification refinement is discussed. Two formal verification tools, the Stanford Temporal Prover (STeP) and the Simple Promela Interpreter (SPIN), are adopted into SAM to develop the initial models. Fourth, formalization and refinement of security issues are studied. A method for security enforcement in SAM is proposed. The Role-Based Access Control model is formalized using predicate transition nets and Z notation. The patterns of enforcing access control and auditing are proposed. Finally, modeling and refining a life insurance system is used to demonstrate how to apply the refinement patterns for software architecture design using SAM and how to integrate the access control model. ^ The results of this dissertation demonstrate that a refinement method is an effective way to develop a high assurance system. The method developed in this dissertation extends existing work on modeling software architectures using SAM and makes SAM a more usable and valuable formal tool for software architecture design. ^

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Book review of: J. Liceras, H. Zobl, and H. Goodluck (eds.), 2008, The Role of Formal Features in Second Language Acquisition. London/New York: Lawrence Erlbaum Associates, 577 pages, ISBN: 0-8058-5354-5.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

The goal of this chapter is to lay out the central themes of heritage language acquisition research adopting a formal/theoretical linguistic perspective.  Specifically, we aim to provide a detailed discussion of the nature of heritage language grammars. In doing so, we will address the debates on how to explain heritage speaker competence differences from monolingual baselines and more. This chapter will not be limited to discussions of Spanish as a heritage language, but rather will highlight the important role that Spanish has played and will continue to play in the development of heritage language acquisition studies. Finally, we will offer some comments/insights on how the information covered regarding the formal linguistic properties of heritage speaker knowledge should be considered for and implemented in heritage language pedagogies and thus dealing with heritage speakers in the classroom setting.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Wire is a intermediate language to enable static program analysis on low level objects such as native executables. It has practical benefit in analysing the structure and semantics of malware, or for identifying software defects in closed source software. In this paper we describe how an executable program is disassembled and translated to the Wire intermediate language. We define the formal syntax and operational semantics of Wire and discuss our justifications for its language features. We use Wire in our previous work Malwise, a malware variant detection system. We also examine applications for when a formally defined intermediate language is given. Our results include showing the semantic equivalence between obfuscated and non obfuscated code samples. These examples stem from the obfuscations commonly used by malware.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

BACKGROUND: The role of the language network in the pathophysiology of formal thought disorder has yet to be elucidated. AIMS: To investigate whether specific grey-matter deficits in schizophrenic formal thought disorder correlate with resting perfusion in the left-sided language network. METHOD: We investigated 13 right-handed patients with schizophrenia and formal thought disorder of varying severity and 13 matched healthy controls, using voxel-based morphometry and magnetic resonance imaging perfusion measurement (arterial spin labelling). RESULTS: We found positive correlations between perfusion and the severity of formal thought disorder in the left frontal and left temporoparietal language areas. We also observed bilateral deficits in grey-matter volume, positively correlated with the severity of thought disorder in temporoparietal areas and other brain regions. The results of the voxel-based morphometry and the arterial spin labelling measurements overlapped in the left posterior superior temporal gyrus and left angular gyrus. CONCLUSIONS: Specific grey-matter deficits may be a risk factor for state-related dysfunctions of the left-sided language system, leading to local hyperperfusion and formal thought disorder.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

"Supported in part by Contract AT(11-1)-1018 with the U.S. Atomic Energy Commission and the Advanced Research Projects Agency."

Relevância:

40.00% 40.00%

Publicador:

Resumo:

This paper presents a formal but practical approach for defining and using design patterns. Initially we formalize the concepts commonly used in defining design patterns using Object-Z. We also formalize consistency constraints that must be satisfied when a pattern is deployed in a design model. Then we implement the pattern modeling language and its consistency constraints using an existing modeling framework, EMF, and incorporate the implementation as plug-ins to the Eclipse modeling environment. While the language is defined formally in terms of Object-Z definitions, the language is implemented in a practical environment. Using the plug-ins, users can develop precise pattern descriptions without knowing the underlying formalism, and can use the tool to check the validity of the pattern descriptions and pattern usage in design models. In this work, formalism brings precision to the pattern language definition and its implementation brings practicability to our pattern-based modeling approach.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Previous research has demonstrated the importance of the qualities of the teacher-child relationship on children’s development. Close teacher-child relationships are especially important for children at risk. Positive relationships have been shown to have beneficial effects on children’s social and academic development (Birch & Ladd, 1997; Pianta & Stuhlman, 2004). Children with language difficulties are likely to face increased risks with regard to long term social and academic outcomes. The purpose of the current research was to gain greater understanding of the qualities of teacher-child relationships for young children with parent reported language concerns. The research analyses completed for this thesis involved the use of data from the public-access database of Growing Up in Australia: The Longitudinal Study of Australian Children (LSAC). LSAC is a longitudinal study involving a nationally representative sample of 10,000 Australian children. Data are being collected biennially from 2004 (Wave 1 data collection) until 2010 (Wave 4 data collection). LSAC has a cross-sequential research design involving two cohorts, an infant cohort (0-1 year at age of recruitment) and a kindergarten cohort (4-5 years at age of recruitment). Two studies are reported in this thesis using data for the LSAC Kindergarten Cohort which had 4983 child participants at recruitment. Study 1 used Wave 1 data to identify the differences between teacher-child relationship qualities for children with parent reported language concerns and their peers. Children identified by parents for whom concerns were held about their receptive and expressive language, as measured by items from the Parents’ Evaluation of Developmental Status (PEDS) (Glascoe, 2000) were the target (at risk) group in the study (n = 210). A matched case control group of peers (n = 210), matched on the child characteristics of sex, age, cultural and linguistic differences (CALD), and socio-economic positioning (SEP), were the comparison group for this analysis. Teacher-child relationship quality was measured by teacher reports on the Closeness and Conflict scales from the short version of the Student-Teacher Relationship Scale (STRS) (Pianta, 2001). There were statistically significant differences in the levels of closeness and conflict between the two groups. The target group had relationships with their teachers that had lower levels of closeness and higher levels of conflict than the control group. Study 2 reports analyses that examined the stability of the qualities of the teacher-child relationships at Wave 1 (4-5 years) and the qualities of the teacher-child relationships at Wave 2 (6-7 years). This time frame crosses the period of the children’s transition to school. The study examined whether early patterns in the qualities of the teacher-child relationship for children with parent reported language concerns at Wave 1 predicted the qualities of the teacher-child relationship outcomes in the early years of formal school. The sample for this study consisted of the group of children identified with PEDS language concerns at Wave 1 who also had teacher report data at Wave 2 (n = 145). Teacher-child relationship quality at Wave 1 and Wave 2 was again measured by the STRS scales of Closeness and Conflict. Results from multiple regression models indicated that teacher-child relationship quality at Wave 1 significantly contributed to the prediction of the quality of the teacher-child relationship at Wave 2, beyond other predictor variables included in the regression models. Specifically, Wave 1 STRS Closeness scores were the most significant predictor for STRS Closeness scores at Wave 2, while Wave 1 STRS Conflict scores were the only significant predictor for Wave 2 STRS Conflict outcomes. These results indicate that the qualities of the teacher-child relationship experienced prior to school by children with parent reported language concerns remained stable across transitions into formal schooling at which time the child had a different teacher. The results of these studies provide valuable insight into the nature of teacher-child relationship quality for young children with parent reported language concerns. These children experienced teacher-child relationships of a lower quality when compared with peers and, additionally, the qualities of these relationships prior to formal schooling were predictive of the qualities of the relationships in the early years of formal schooling. This raises concerns, given the increased risks of poorer social and academic outcomes already faced by children with language difficulties, that these early teacher-child relationships have an impact on future teacher-child relationships. Results of these studies are discussed with these considerations in mind and also discussed in terms of the implications for educational theory, policy and practice.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Concerns raised in educational reports about school science in terms of students. outcomes and attitudes, as well as science teaching practices prompted investigation into science learning and teaching practices at the foundational level of school science. Without science content and process knowledge, understanding issues of modern society and active participation in decision-making is difficult. This study contended that a focus on the development of the language of science could enable learners to engage more effectively in learning science and enhance their interest and attitudes towards science. Furthermore, it argued that explicit teaching practices where science language is modelled and scaffolded would facilitate the learning of science by young children at the beginning of their formal schooling. This study aimed to investigate science language development at the foundational level of school science learning in the preparatory-school with students aged five and six years. It focussed on the language of science and science teaching practices in early childhood. In particular, the study focussed on the capacity for young students to engage with and understand science language. Previous research suggests that students have difficulty with the language of science most likely because of the complexities and ambiguities of science language. Furthermore, literature indicates that tensions transpire between traditional science teaching practices and accepted early childhood teaching practices. This contention prompted investigation into means and models of pedagogy for learning foundational science language, knowledge and processes in early childhood. This study was positioned within qualitative assumptions of research and reported via descriptive case study. It was located in a preparatory-school classroom with the class teacher, teacher-aide, and nineteen students aged four and five years who participated with the researcher in the study. Basil Bernstein.s pedagogical theory coupled with Halliday.s Systemic Functional Linguistics (SFL) framed an examination of science pedagogical practices for early childhood science learning. Students. science learning outcomes were gauged by focussing a Hallydayan lens on their oral and reflective language during 12 science-focussed episodes of teaching. Data were collected throughout the 12 episodes. Data included video and audio-taped science activities, student artefacts, journal and anecdotal records, semi-structured interviews and photographs. Data were analysed according to Bernstein.s visible and invisible pedagogies and performance and competence models. Additionally, Halliday.s SFL provided the resource to examine teacher and student language to determine teacher/student interpersonal relationships as well as specialised science and everyday language used in teacher and student science talk. Their analysis established the socio-linguistic characteristics that promoted science competencies in young children. An analysis of the data identified those teaching practices that facilitate young children.s acquisition of science meanings. Positive indications for modelling science language and science text types to young children have emerged. Teaching within the studied setting diverged from perceived notions of common early childhood practices and the benefits of dynamic shifting pedagogies were validated. Significantly, young students demonstrated use of particular specialised components of school-science language in terms of science language features and vocabulary. As well, their use of language demonstrated the students. knowledge of science concepts, processes and text types. The young students made sense of science phenomena through their incorporation of a variety of science language and text-types in explanations during both teacher-directed and independent situations. The study informs early childhood science practices as well as practices for foundational school science teaching and learning. It has exposed implications for science education policy, curriculum and practices. It supports other findings in relation to the capabilities of young students. The study contributes to Systemic Functional Linguistic theory through the development of a specific resource to determine the technicality of teacher language used in teaching young students. Furthermore, the study contributes to methodology practices relating to Bernsteinian theoretical perspectives and has demonstrated new ways of depicting and reporting teaching practices. It provides an analytical tool which couples Bernsteinian and Hallidayan theoretical perspectives. Ultimately, it defines directions for further research in terms of foundation science language learning, ongoing learning of the language of science and learning science, science teaching and learning practices, specifically in foundational school science, and relationships between home and school science language experiences.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The official need for content teachers to teach the language features of their fields has never been greater in Australia than now. In 2012, the recently formed national curriculum board announced that all teachers are responsible for the English language development of students whose first language or dialect is not Standard Australian English (SAE). This formal endorsement is an important juncture regarding the way expertise might be developed, perceived and exchanged between content and language teachers through collaboration, in order for the goals of English language learners in content areas to be realised. To that end, we conducted an action research project to explore and extend the reading strategies pedagogy of one English language teacher who teaches English language learners in a parallel junior high school Geography program. Such pedagogy will be valuable for all teachers as they seek to contribute to English language development goals as outlined in national curricula.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Parents are encouraged to read with their children from an early age because shared book reading helps children to develop their language and early literacy skills. A pragmatic Randomised Controlled Trial (RCT) research design was adopted to investigate the influence of two forms of a shared reading intervention (Dialogic Reading and Dialogic Reading with the addition of Print Referencing) on children’s language and literacy skills. Dialogic reading is a validated shared reading intervention that has been shown to improve children’s oral language skills prior to formal schooling (Whitehurst & Lonigan, 1998). Print referencing is another form of shared reading intervention that has the potential to have effects on children’s print knowledge as they begin school (Justice & Ezell, 2002). However, training parents to use print referencing strategies at home has not been researched extensively although research findings indicate its effectiveness when used by teachers in the early years of school. Eighty parents of Preparatory year children from three Catholic schools in low income areas in the outer suburbs of a metropolitan city were trained to deliver specific shared reading strategies in an eight-week home intervention. Parents read eight books to their children across the period of the intervention. Each book was requested to be read at least three times a week. There were 42 boys and 38 girls ranging in age from 4.92 years to 6.25 years (M=5.53, SD=0.33) in the sample. The families were randomly assigned to three groups: Dialogic Reading (DR); Dialogic Reading with the addition of Print Referencing (DR + PR); and a Control group. Six measures were used to assess children’s language skills at pre and post, and follow-up (three months after the intervention). These measures assessed oral language (receptive and expressive vocabulary), phonological awareness skills (rhyme, word completion), alphabet knowledge, and concepts about print. Results of the intervention showed that there were significant differences from pre to post between the two intervention groups and the control group on three measures: expressive vocabulary, rhyme, and concepts about print. The shared reading strategies delivered by parents of the dialogic reading, and dialogic reading with the addition of print referencing, showed promising results to develop children’s oral language skills in terms of expressive vocabulary and rhyme, as well as understanding of the concepts about print. At follow-up, when the children entered Year 1, the two intervention groups (DR and DR + PR) group had significantly maintained their knowledge of concepts about prints when compared with the control group. Overall, the findings from this intervention study did not show that dialogic reading with the addition of print referencing had stronger effects on children’s early literacy skills than dialogic reading alone. The research also explored if pre-existing family factors impacted on the outcomes of the intervention from pre to post. The relationships between maternal education and home reading practices prior to intervention and child outcomes at post were considered. However, there were no significant effects of maternal education and home literacy activities on child outcomes at post. Additionally, there were no significant effects for the level of compliance of parents with the intervention program in terms of regular weekly reading to children during the intervention period on child outcomes at post. These non-significant findings are attributed to the lack of variability in the recruited sample. Parents participating in the intervention had high levels of education, although they were recruited from schools in low socio-economic areas; parents were already highly engaged in home literacy activities at recruitment; and the parents were highly compliant in reading regularly to their child during the intervention. Findings of the current study did show that training in shared reading strategies enhanced children’s early language and literacy skills. Both dialogic reading and dialogic reading with the addition of print referencing improved children’s expressive vocabulary, rhyme, and concepts about print at post intervention. Further research is needed to identify how, and if, print referencing strategies used by parents at home can be effective over and above the use of dialogic reading strategies. In this research, limitations of sample size and the nature of the intervention to use print referencing strategies at home may have restricted the opportunities for this research study to find more effects on children’s emergent literacy skills or for the effectiveness of combining dialogic reading with print referencing strategies. However, these results did indicate that there was value in teaching parents to implement shared reading strategies at home in order to improve early literacy skills as children begin formal schooling.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The aim was to analyse the growth and compositional development of the receptive and expressive lexicons between the ages 0,9 and 2;0 in the full-term (FT) and the very-low-birth-weight (VLBW) children who are acquiring Finnish. The associations between the expressive lexicon and grammar at 1;6 and 2;0 in the FT children were also studied. In addition, the language skills of the VLBW children at 2;0 were analysed, as well as the predictive value of early lexicon to the later language performance. Four groups took part in the studies: the longitudinal (N = 35) and cross-sectional (N = 146) samples of the FT children, and the longitudinal (N = 32) and cross-sectional (N = 66) samples of VLBW children. The data was gathered by applying of the structured parental rating method (the Finnish version of the Communicative Development Inventory), through analysis of the children´s spontaneous speech and by administering a a formal test (Reynell Developmental Language Scales). The FT children acquired their receptive lexicons earlier, at a faster rate and with larger individual variation than their expressive lexicons. The acquisition rate of the expressive lexicon increased from slow to faster in most children (91%). Highly parallel developmental paths for lexical semantic categories were detected in the receptive and expressive lexicons of the Finnish children when they were analysed in relation to the growth of the lexicon size, as described in the literature for children acquiring other languages. The emergence of grammar was closely associated with expressive lexical growth. The VLBW children acquired their receptive lexicons at a slower rate and had weaker language skills at 2;0 than the full-term children. The compositional development of both lexicons happened at a slower rate in the VLBW children when compared to the FT controls. However, when the compositional development was analysed in relation to the growth of lexicon size, this development occurred qualitatively in a nearly parallel manner in the VLBW children as in the FT children. Early receptive and expressive lexicon sizes were significantly associated with later language skills in both groups. The effect of the background variables (gender, length of the mother s basic education, birth weight) on the language development in the FT and the VLBW children differed. The results provide new information of early language acquisition by the Finnish FT and VLBW children. The results support the view that the early acquisition of the semantic lexical categories is related to lexicon growth. The current findings also propose that the early grammatical acquisition is closely related to the growth of expressive vocabulary size. The language development of the VLBW children should be followed in clinical work.