604 research outputs found

    The lives and legacies of Iona and Peter Opie

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    This article outlines the biographies of Iona (1923 –) and Peter (1918–1982) Opie and describes their aims, methods and theoretical orientation with particular reference to their work on children's play and games in the third quarter of the twentieth century. The account illustrates their separate identities as well as portraying the joint working relationship they built up as a husband-and-wife team. The Opies’ reputation as pioneer researchers into children's folklore in the UK and beyond derives from their publications, which have become classics in the field and widely read by a general audience as well as by academics and professionals. The Opies’ scholarship and its reception and impact are considered here. The article also describes the Opies’ archival collection, especially their ‘working papers’ and sound recordings, and highlights the importance of evaluating the Opies’ contribution in terms of their archival legacy, as well as their published works

    From "Breathless Catalogue' to "Beyond Text': A Hundred Years of Children's Folklore Collecting

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    This lecture draws attention to research into children’s folklore in Britain from the last century, stressing its potential to inform understandings of contemporary childhoods, particularly children’s play. The emphasis is on archival sources, such as the collections of Norman Douglas, James Ritchie, and Iona and Peter Opie. The changing nature of contemporary evidence, such as children’s self-produced films of their play shared on YouTube, is also illustrated, and the importance of a multimodal approach stressed. The author compares the historical sources with the collectors’ published work, and highlights the need for rigour in appraising these differing forms of evidence

    Infection or inflection? Reflecting on constructions of children and play through the prism of the COVID-19 pandemic

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    During crisis times, what children are playing and what grown-ups think their games signify can become a focus of adult anxiety. The Play Observatory, a COVID-19 research project, drew on folklore studies and cultural histories of childhood to collect, document and understand what children were playing and doing during extraordinary times, in ways which were meaningful to children themselves. This article discusses some of the children’s and families’ contributions, juxtaposed with children’s contributions to the archive of childhood folklorists Iona and Peter Opie, to highlight and contest adultist interpretations around children’s play during difficult times. We suggest that these interpretations are rooted in particular social constructions of the child, of childhood and of play that reflect themes of innocence, purity and vulnerability, and the need for adult protection from contamination, both material and symbolic. We introduce the idea of ‘inflection’ to suggest how habitual and perennial forms of play may be made to temporarily accommodate contemporary issues by the players as opposed to the play (and hence the child) being ‘infected’ with troubling or distressing themes which detract from idealised constructs of childhood

    Validation of Ultrahigh Dependability for Software-Based Systems

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    Modern society depends on computers for a number of critical tasks in which failure can have very high costs. As a consequence, high levels of dependability (reliability, safety, etc.) are required from such computers, including their software. Whenever a quantitative approach to risk is adopted, these requirements must be stated in quantitative terms, and a rigorous demonstration of their being attained is necessary. For software used in the most critical roles, such demonstrations are not usually supplied. The fact is that the dependability requirements often lie near the limit of the current state of the art, or beyond, in terms not only of the ability to satisfy them, but also, and more often, of the ability to demonstrate that they are satisfied in the individual operational products (validation). We discuss reasons why such demonstrations cannot usually be provided with the means available: reliability growth models, testing with stable reliability, structural dependability modelling, as well as more informal arguments based on good engineering practice. We state some rigorous arguments about the limits of what can be validated with each of such means. Combining evidence from these different sources would seem to raise the levels that can be validated; yet this improvement is not such as to solve the problem. It appears that engineering practice must take into account the fact that no solution exists, at present, for the validation of ultra-high dependability in systems relying on complex software

    Differential Geometry applied to Acoustics : Non Linear Propagation in Reissner Beams

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    Although acoustics is one of the disciplines of mechanics, its "geometrization" is still limited to a few areas. As shown in the work on nonlinear propagation in Reissner beams, it seems that an interpretation of the theories of acoustics through the concepts of differential geometry can help to address the non-linear phenomena in their intrinsic qualities. This results in a field of research aimed at establishing and solving dynamic models purged of any artificial nonlinearity by taking advantage of symmetry properties underlying the use of Lie groups. The geometric constructions needed for reduction are presented in the context of the "covariant" approach.Comment: Submitted to GSI2013 - Geometric Science of Informatio

    Domain Walls in Two-Component Dynamical Lattices

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    We introduce domain-wall (DW) states in the bimodal discrete nonlinear Schr{\"{o}}dinger equation, in which the modes are coupled by cross phase modulation (XPM). By means of continuation from various initial patterns taken in the anti-continuum (AC) limit, we find a number of different solutions of the DW type, for which different stability scenarios are identified. In the case of strong XPM coupling, DW configurations contain a single mode at each end of the chain. The most fundamental solution of this type is found to be always stable. Another solution, which is generated by a different AC pattern, demonstrates behavior which is unusual for nonlinear dynamical lattices: it is unstable for small values of the coupling constant CC (which measures the ratio of the nonlinearity and coupling lengths), and becomes stable at larger CC. Stable bound states of DWs are also found. DW configurations generated by more sophisticated AC patterns are identified as well, but they are either completely unstable, or are stable only at small values of CC. In the case of weak XPM, a natural DW solution is the one which contains a combination of both polarizations, with the phase difference between them 0 and π\pi at the opposite ends of the lattice. This solution is unstable at all values of CC, but the instability is very weak for large CC, indicating stabilization as the continuum limit is approached. The stability of DWs is also verified by direct simulations, and the evolution of unstable DWs is simulated too; in particular, it is found that, in the weak-XPM system, the instability may give rise to a moving DW.Comment: 14 pages, 14 figures, Phys. Rev. E (in press

    Foreground removal from CMB temperature maps using an MLP neural network

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    One of the main obstacles in extracting the Cosmic Microwave Background (CMB) signal from observations in the mm-submm range is the foreground contamination by emission from galactic components: mainly synchrotron, free-free and thermal dust emission. Due to the statistical nature of the intrinsic CMB signal it is essential to minimize the systematic errors in the CMB temperature determinations. Following the available knowledge of the spectral behavior of the galactic foregrounds simple, power law-like spectra have been assumed. The feasibility of using a simple neural network for extracting the CMB temperature signal from the combined CMB and foreground signals has been investigated. As a specific example, we have analysed simulated data, like that expected from the ESA Planck Surveyor mission. A simple multilayer perceptron neural network with 2 hidden layers can provide temperature estimates, over more than 80 percent of the sky, that are to a high degree uncorrelated with the foreground signals. A single network will be able to cover the dynamic range of the Planck noise level over the entire sky.Comment: Accepted for publication in Astrophysics and Space Scienc

    VFISV: Very Fast Inversion of the Stokes Vector for the Helioseismic and Magnetic Imager

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    In this paper we describe in detail the implementation and main properties of a new inversion code for the polarized radiative transfer equation (VFISV: Very Fast inversion of the Stokes vector). VFISV will routinely analyze pipeline data from the Helioseismic and Magnetic Imager (HMI) on-board of the Solar Dynamics Observatory (SDO). It will provide full-disk maps (4096×\times4096 pixels) of the magnetic field vector on the Solar Photosphere every 10 minutes. For this reason VFISV is optimized to achieve an inversion speed that will allow it to invert 16 million pixels every 10 minutes with a modest number (approx. 50) of CPUs. Here we focus on describing a number of important details, simplifications and tweaks that have allowed us to significantly speed up the inversion process. We also give details on tests performed with data from the spectropolarimeter on-board of the Hinode spacecraft.Comment: 23 pages, 9 figures (2 color). Submitted for publication to Solar Physic
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