4,983,817 research outputs found

    Testing the RPI data for consistency with the theory of the cost-of-living index

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    This paper tests the published section level price and weight data used in the compilation of the UK Retail Prices Index for consistency with the theory of the cost-of-living index. We use a nonparametric test of theoretical consistency and bootstrap statistical methods to estimate the probability of consistency

    Testing the RPI data for consistency with the theory of the cost-of-living index

    Get PDF
    This paper tests the published section level price and weight dataused in the compilation of the UK Retail Prices Index for consistencywith the theory of the cost-of-living index. We use a nonparametric testof theoretical consistency and bootstrap statistical methods to estimatethe probability of consistency.

    Development of a Sun centred sky camera for use in UV measurements

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    Managing uncertainty: a review of food system scenario analysis and modelling

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    Complex socio-ecological systems like the food system are unpredictable, especially to long-term horizons such as 2050. In order to manage this uncertainty, scenario analysis has been used in conjunction with food system models to explore plausible future outcomes. Food system scenarios use a diversity of scenario types and modelling approaches determined by the purpose of the exercise and by technical, methodological and epistemological constraints. Our case studies do not suggest Malthusian futures for a projected global population of 9 billion in 2050; but international trade will be a crucial determinant of outcomes; and the concept of sustainability across the dimensions of the food system has been inadequately explored so far. The impact of scenario analysis at a global scale could be strengthened with participatory processes involving key actors at other geographical scales. Food system models are valuable in managing existing knowledge on system behaviour and ensuring the credibility of qualitative stories but they are limited by current datasets for global crop production and trade, land use and hydrology. Climate change is likely to challenge the adaptive capacity of agricultural production and there are important knowledge gaps for modelling research to address

    Generalized Inpainting Method for Hyperspectral Image Acquisition

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    A recently designed hyperspectral imaging device enables multiplexed acquisition of an entire data volume in a single snapshot thanks to monolithically-integrated spectral filters. Such an agile imaging technique comes at the cost of a reduced spatial resolution and the need for a demosaicing procedure on its interleaved data. In this work, we address both issues and propose an approach inspired by recent developments in compressed sensing and analysis sparse models. We formulate our superresolution and demosaicing task as a 3-D generalized inpainting problem. Interestingly, the target spatial resolution can be adjusted for mitigating the compression level of our sensing. The reconstruction procedure uses a fast greedy method called Pseudo-inverse IHT. We also show on simulations that a random arrangement of the spectral filters on the sensor is preferable to regular mosaic layout as it improves the quality of the reconstruction. The efficiency of our technique is demonstrated through numerical experiments on both synthetic and real data as acquired by the snapshot imager.Comment: Keywords: Hyperspectral, inpainting, iterative hard thresholding, sparse models, CMOS, Fabry-P\'ero

    Image quality and security through nonlinear joint transform encryption

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    Postprint (published version

    The impact of agri-environment schemes on pollination services in England

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    Agri-environment schemes fund landholders to manage land to achieve environmental objectives and other public goods. Previous research has shown that individual scheme interventions can boost wild pollinator populations locally. However, the effect of an entire scheme at a national scale has never previously been assessed. The location of every intervention implemented in England during 2016 was mapped and schemes’ predicted impact on bee abundance and pollination services was modelled using a validated, processbased spatial model (poll4pop), which simulates foraging and population dynamics. The study considered four wild bee guilds (incorporating bumblebees and solitary bees) and their visitation rates to four pollinator-dependent crops (oilseed rape, field beans, orchard fruit and strawberries). The modelling predicted that the scheme significantly increased ground-nesting (but not tree/cavitynesting) bee populations nationally. There were no significant increases in crop visitation at national scale, but some locally significant increases in ground-nesting bumblebee visitation to oilseed rape and field beans were predicted. Linear regression at 10 km scale was used to determine which interventions were driving increased oilseed rape and field bean visitation and found that hedgerow/woodland edge management dominated, due to high resource quality. Floral margins were estimated to provide more limited benefit, due to later resource phenology and low uptake. Fallow also had a strong effect, despite lower relative resource quality, implying effective placement with respect to crops. Finally, the effect of additional tree-planting interventions (hedgerows, agroforestry, and woodland) on bumblebee abundance and crop visitation (oilseed rape, field beans) was studied. This showed that hedgerow planting would deliver the greatest increase in bumblebee abundance, whereas fruit or willow agroforestry would increase crop visitation the most, due to higher co-location. Based on these findings, recommendations are set out for design of future schemes to help deliver greater and more resilient crop pollination services in arable landscapes
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