314 research outputs found

    Updates in a Rule based Language for Objects

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    The integration of object-oriented concepts into deductive databases has been investigated for a certain time now. Various approaches to incorporate updates into deduction have been proposed. The current paper presents an approach which is based on object versioning; different versions of one object may be created and referenced during an update-process. By means of such versions it becomes possible to exert explicit control on the update process during bottom-up evaluation in a rather intuitive way. The units for updates are the result sets of base methods, i.e. methods, whose results are stored in the object-base and are not defined by rules. However, the update itself may be defined by rules. Update-programs have fixpoint semantics; the fixpoint can be computed by a bottom-up evaluation according to a certain stratification

    A grounded theory of software process improvement model adoption

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    This study, using a grounded theory methodology, analyzed data collected from software developers and IT professionals on software process improvement (SPI) adoption. The study is presented within a backdrop of organizational change steps described by John P. Kotter in his 1996 book, Leading Change. Software quality problems and failures have caused many financial losses, injuries, and even deaths. In the mid 1980s, as a means of mitigating these problems, the Department of Defense (DoD) and Carnegie Mellon University (CMU) began work on the Capability Maturity Model (CMMRTM) In 2001, the model was superseded by a more robust model, the Capability Maturity Model Integration (CMMIRTM) These models were designed to provide descriptive, key process improvement areas for organizations to achieve greater maturity in their software and systems development. Organizations could then be appraised at specific maturity levels. According to CMU, SPI improves quality and reliability of software products. The DoD and several organizations now require companies to be appraised at a certain maturity level prior to being awarded a contract. From the onset, there have been difficulties in the adoption of these SPI models. Some of these difficulties can be attributed to organizational change issues. Through grounded theory analysis, a substantive theory was developed, The Theory of Software Process Improvement Model Adoption. This theory contributes to the body of knowledge by providing data and analysis from numerous IT professionals and software developers. This study also provides suggested key organizational change concerns for better SPI adoption practices

    Systems for reuse, repurposing and upcycling of existing building components

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    The construction industry uses natural resources intensively, and causes significant carbon emissions in processing resources to supply useful materials and components. Demolition generates considerable physical waste, accompanied by wastage of the impacts embodied in existing building components. This project explores the failure to capitalise on these embodied impacts, and adopts a mixed methods approach to develop interventions and identify potential mechanisms for change. The main contributions of the thesis are: Firstly, an exploration of the notion of ‘component management’. This challenges the assumption that components removed from the building stock must either be: a) directly reused, which can often be impractical, and is rarely given due attention, or b) sent to waste management, which wastes embodied impacts. Instead, the role and implementation of repurposing and upcycling are described, alongside a procedure for comprehensively checking the practicality of direct reuse; Secondly, the development of an urban-level ‘triage’: a process to separate out components for reuse, repurposing and upcycling, from those for which downcycling or energy recovery are the best option. Key to the triage is an information system; the thesis reviews current means of understanding existing buildings as material banks and presents a new approach to gathering this information; Thirdly, a proposal for an innovative manufacturing enterprise using secondary timber in a new product: cross-laminated secondary timber. This provides an exemplar case study of the potential for industrial-scale upcycling. A proof of concept study is presented, with a preliminary examination of technical feasibility and leading the way for additional investigation of socio-economic and environmental sustainability, and, ideally, future pilot- and commercial-scale implementation. The implications of this product case study are synthesised with the other parts of the thesis in a discussion of areas for future research, policy and practical action to evolve a more nuanced and sustainable management of existing building components

    MATrA: meta-modelling approach to traceability for avionics

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    PhD ThesisTraceability is the common term for mechanisms to record and navigate relationships between artifacts produced by development and assessment processes. Effective management of these relationships is critical to the success of projects involving the development of complex aerospace products. Practitioners use a range of notations to model aerospace products (often as part of a defined technique or methodology). Those appropriate to electrical and electronic systems (avionics) include Use Cases for requirements, Ada for development and Fault Trees for assessment (others such as PERT networks support product management). Most notations used within the industry have tool support, although a lack of well-defined approaches to integration leads to inconsistencies and limits traceability between their respective data sets (internal models). Conceptually, the artifacts produced using such notations populate four traceability dimensions. Of these, three record links between project artifacts (describing the same product), while the fourth relates artifacts across different projects (and hence products), and across product families within the same project. The scope of this thesis is to define a meta-framework that characterises traceability dimensions for aerospace projects, and then to propose a concrete framework capturing the syntax and semantics of notations used in developing avionics for such projects which enables traceability across the four dimensions. The concrete framework is achieved by exporting information from the internal models of tools supporting these notations to an integrated environment consisting of. i) a Workspace comprising a set of structures or meta-models (models describing models) expressed in a common modelling language representing selected notations (including appropriate extensions reflecting the application domain); ii) well-formedness constraints over these structures capturing properties of the notations (and again, reflecting the domain); and iii) associations between the structures. To maintain consistency and identify conflicts, elements of the structures are verified against a system model that defines common building blocks underlying the various notations. The approach is evaluated by (partial) tool implementation of the structures which are populated using case study material derived from actual commercial specifications and industry standards

    An Evaluation of the ‘Philosophy for Children’ programme: The impact on Cognitive and Non-Cognitive Skills

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    Philosophy for Children (P4C) is a school-based intervention currently implemented in more than 60 countries. This thesis examines the evidence regarding the effectiveness of Philosophy for Children for developing pupils’ cognitive and non-cognitive skills. Three different approaches were used. A systematic literature review was conducted of the evidence published in the last 40 years. A new comparative evaluation study was conducted with Year 5 pupils in 17 primary schools in England (N = 547 pupils in the intervention group, N= 270 in the comparison group). The intervention lasted for an academic year, and a pre-test and a post-test were given at the beginning and end of the school year to evaluate students’ critical thinking and creativity. Secondary data analysis of the National Pupil Database (NPD) from the Department of Education was used to examine the long-term effect of P4C implementation on attainment (reading, writing, maths). The results of 34 schools which implemented P4C during Key Stage 2 (2011-2015) were compared with 14,791 mainstream schools in England which did not, and the same analysis was repeated based only on these pupils in both groups known to be eligible for Free School Meals during the last six years (as an assessment of the impact of the P4C on narrowing the poverty attainment gap). The review results suggested that P4C generally has a positive impact on reasoning skills. In most studies, P4C also has a positive impact on literacy and some non-cognitive skills. However, the new comparative evaluation study found no evidence that P4C has a positive impact on Year 5 students’ critical thinking or creativity. This comparative study has some limitations in terms of design and inevitable attrition. The more robust secondary data analysis showed that students eligible for Free School Meals develop their reading and writing more after long-term P4C implementation than in non-P4C schools, during Key Stage 2. By combining all of the evidence from the review, comparative evaluation study and secondary data analysis, this study suggests that the implementation of P4C in primary schools is still worthwhile, both in its own terms and for its added benefits in terms of cognitive and perhaps non-cognitive outcomes. The programme is likely to help improve students’ reasoning skills. P4C can improve the literacy of disadvantaged students in the classrooms, relative to their peers, and so contribute towards closing the attainment gap between advantaged and disadvantaged students. However, the new evaluation creates a caution about what can be expected from P4C and, if it used, the programme may need adjusting in order to provide opportunities for practicing a wider range of thinking skills
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