2,186 research outputs found

    Software fault characteristics: A synthesis of the literature

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    Faults continue to be a significant problem in software. Understanding the nature of these faults is important for practitioners and researchers. There are many published fault characteristics schemes but no one scheme dominates. Consequently it is difficult for practitioners to effectively evaluate the nature of faults in their software systems, and it is difficult for researchers to compare the types of faults found by different fault detection techniques. In this paper we synthesise previous fault characteristics schemes into one comprehensive scheme. Our scheme provides a richer view of faults than the previous schemes published and presents a comprehensive, unified approach which accommodates the many previous schemes. A characteristics-based view of faults should be considered by future researchers in the analysis of software faults and in the design and evaluation of new fault detection tools. We recommend that our fault characteristics scheme be used as a benchmark scheme

    Voltage and current spectra for matrix power converters

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    Matrix power converters are used for transforming one alternating-current power supply to another, with different peak voltage and frequency. There are three input lines, with sinusoidally varying voltages which are 120◦ out of phase one from another, and the output is to be delivered as a similar three-phase supply. The matrix converter switches rapidly, to connect each output line in sequence to each of the input lines in an attempt to synthesize the prescribed output voltages. The switching is carried out at high frequency and it is of practical importance to know the frequency spectra of the output voltages and of the input and output currents. We determine in this paper these spectra using a new method, which has significant advantages over the prior default method (a multiple Fourier series technique), leading to a considerably more direct calculation. In particular, the determination of the input current spectrum is feasible here, whereas it would be a significantly more daunting procedure using the prior method instead

    How should we measure psychological resilience in sport performers?

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    Psychological resilience is important in sport because athletes must constantly withstand a wide range of pressures to attain and sustain high performance. To advance psychologists’ understanding of this area, there exists an urgent need to develop a sport-specific measure of resilience. The purpose of this paper is to review psychometric issues in resilience research and to discuss the implications for sport psychology. Drawing on the wider general psychology literature to inform the discussion, the narrative is divided into three main sections relating to resilience and its assessment: adversity, positive adaptation, and protective factors. The first section reviews the different ways that adversity has been measured and considers the potential problems of using items with varying degrees of controllability and risk. The second section discusses the different approaches to assessing positive adaptation and examines the issue of circularity pervasive in resilience research. The final section explores the various issues related to the assessment of protective factors drawing directly from current measures of resilience in other psychology sub-disciplines. The commentary concludes with key recommendations for sport psychology researchers seeking to develop a measure of psychological resilience in athletes

    Effective action in DSR1 quantum field theory

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    We present the one-loop effective action of a quantum scalar field with DSR1 space-time symmetry as a sum over field modes. The effective action has real and imaginary parts and manifest charge conjugation asymmetry, which provides an alternative theoretical setting to the study of the particle-antiparticle asymmetry in nature.Comment: 8 page

    Can we use medical examiners' records for suicide surveillance and prevention research in Nova Scotia?

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    Introduction: Medical examiners' records can contribute to our understanding of the extent of suicide in a population, as well as associated sociodemographic and other factors

    Establishing the baseline in groundwater chemistry in connection with shale-gas exploration: Vale of Pickering, UK

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    The baseline chemistry of groundwater from two aquifers in the Vale of Pickering, North Yorkshire, has been investigated ahead of a proposal to explore for shale gas, planning permission for which has recently been granted. Groundwater in a shallow aquifer including Quaternary and/or Jurassic Kimmeridge Clay deposits shows compositions distinct from a Corallian (Jurassic) Limestone aquifer, reflecting different lithologies and hydrogeological conditions. Corallian groundwaters along the margins of the vale are controlled by reaction with carbonate, with redox conditions varying according to degree of aquifer confinement. Superficial aquifer groundwaters are confined and strongly reducing, with some observed high concentrations of dissolved CH4 (up to 37 mg/L; Feb 2016 data). This appears to be of mixed biogenic-thermogenic origin but further work is needed to determine whether the source includes a deeper hydrocarbon reservoir contributing via fractures, or a shallower source in the Quaternary or Kimmeridge sediments. The data show a shallow aquifer with a high-CH4 baseline which pre-dates any shale-gas activity

    Electric charge quantization and the muon anomalous magnetic moment

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    We investigate some proposals to solve the electric charge quantization puzzle, which simultaneously explain the recent measured deviation on the muon anomalous magnetic moment. For this we assess extensions of the Electro-Weak Standard Model spanning modifications on the scalar sector only. It is interesting to verify that one can have modest extensions which easily account for the solution for both problems.Comment: 20 pages, 1 figures, needs macro axodraw.st

    Furthering alternative cultures of valuation in higher education research

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    The value of higher education is often implicit or assumed in educational research. The underlying and antecedent premises that shape and influence debates about value remain unchallenged which perpetuates the dominant, but limiting, terms of the debate and fosters reductionism. I proceed on the premise that analyses of value are not self–supporting or self-referential but are embedded within prevailing cultures of valuation. I contend that challenging, and providing alternatives to, dominant narratives of higher education requires an appreciation of those cultures. I therefore highlight some of the existing cultures of valuation and their influence. I then propose Sayer’s concept of lay normativity as a culture of valuation and discuss how it translates into the practices of research into higher education, specifically the practice of analysis. I animate the discussion by detecting the presence of lay normativity in the evaluative space of the capability approach

    Sterile Neutrinos in E_6 and a Natural Understanding of Vacuum Oscillation Solution to the Solar Neutrino Puzzle

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    If Nature has chosen the vacuum oscillation solution to the Solar neutrino puzzle, a key theoretical challenge is to understand the extreme smallness of the ΔmνeνX2\Delta m^2_{\nu_e-\nu_X} (1010eV2\sim 10^{-10} eV^2) required for the purpose. We find that in a class of models such as [SU(3)]^3 or its parent group E_6, which contain one sterile neutrino, νis\nu_{is} for each family, the Δmνiνis2\Delta m^2_{\nu_i-\nu_{is}} is proportional to the cube of the lepton Yukawa coupling. Therefore fitting the atmospheric neutrino data then predicts the νeνes\nu_e-\nu_{es} mass difference square to be (memμ)3Δmatmos2\sim (\frac{m_e}{m_{\mu}})^3 \Delta m^2_{atmos}, where the atmospheric neutrino data is assumed to be solved via the νμνμs\nu_{\mu}-\nu_{\mu s} oscillation. This provides a natural explanation of the vacuum oscillation solution to the solar neutrino problem.Comment: 7 pages, UMD-PP-99-109; new references added; no other chang

    Catchment-scale biogeography of riverine bacterioplankton

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    Lotic ecosystems such as rivers and streams are unique in that they represent a continuum of both space and time during the transition from headwaters to the river mouth. As microbes have very different controls over their ecology, distribution and dispersion compared with macrobiota, we wished to explore biogeographical patterns within a river catchment and uncover the major drivers structuring bacterioplankton communities. Water samples collected across the River Thames Basin, UK, covering the transition from headwater tributaries to the lower reaches of the main river channel were characterised using 16S rRNA gene pyrosequencing. This approach revealed an ecological succession in the bacterial community composition along the river continuum, moving from a community dominated by Bacteroidetes in the headwaters to Actinobacteria-dominated downstream. Location of the sampling point in the river network (measured as the cumulative water channel distance upstream) was found to be the most predictive spatial feature; inferring that ecological processes pertaining to temporal community succession are of prime importance in driving the assemblages of riverine bacterioplankton communities. A decrease in bacterial activity rates and an increase in the abundance of low nucleic acid bacteria relative to high nucleic acid bacteria were found to correspond with these downstream changes in community structure, suggesting corresponding functional changes. Our findings show that bacterial communities across the Thames basin exhibit an ecological succession along the river continuum, and that this is primarily driven by water residence time rather than the physiochemical status of the river
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