46 research outputs found

    Sensor node localisation using a stereo camera rig

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    In this paper, we use stereo vision processing techniques to detect and localise sensors used for monitoring simulated environmental events within an experimental sensor network testbed. Our sensor nodes communicate to the camera through patterns emitted by light emitting diodes (LEDs). Ultimately, we envisage the use of very low-cost, low-power, compact microcontroller-based sensing nodes that employ LED communication rather than power hungry RF to transmit data that is gathered via existing CCTV infrastructure. To facilitate our research, we have constructed a controlled environment where nodes and cameras can be deployed and potentially hazardous chemical or physical plumes can be introduced to simulate environmental pollution events in a controlled manner. In this paper we show how 3D spatial localisation of sensors becomes a straightforward task when a stereo camera rig is used rather than a more usual 2D CCTV camera

    Inkjet printed conductive polymer-based beam-splitters for terahertz applications

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    Terahertz beam-splitters are fabricated from conductive polymers inkjet printed onto an acetate film substrate. The principle is a significant evolution of the recently proposed ultra-thin beam-splitter realized using silver conductive paint. The splitting ratios of the beam-splitters are dependent on the thickness and conductivity of the conductive polymer layer, allowing for any splitting ratio to be achieved accurately from a controlled printing process. As the processing technology of conductive polymers matures, this approach will allow for low cost and accurate fabrication of THz beam-splitters with a predefined near frequency-independent splitting ratio, in contrast to the commonly used float zone silicon wafers

    The seeds of divergence: the economy of French North America, 1688 to 1760

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    Generally, Canada has been ignored in the literature on the colonial origins of divergence with most of the attention going to the United States. Late nineteenth century estimates of income per capita show that Canada was relatively poorer than the United States and that within Canada, the French and Catholic population of Quebec was considerably poorer. Was this gap long standing? Some evidence has been advanced for earlier periods, but it is quite limited and not well-suited for comparison with other societies. This thesis aims to contribute both to Canadian economic history and to comparative work on inequality across nations during the early modern period. With the use of novel prices and wages from Quebec—which was then the largest settlement in Canada and under French rule—a price index, a series of real wages and a measurement of Gross Domestic Product (GDP) are constructed. They are used to shed light both on the course of economic development until the French were defeated by the British in 1760 and on standards of living in that colony relative to the mother country, France, as well as the American colonies. The work is divided into three components. The first component relates to the construction of a price index. The absence of such an index has been a thorn in the side of Canadian historians as it has limited the ability of historians to obtain real values of wages, output and living standards. This index shows that prices did not follow any trend and remained at a stable level. However, there were episodes of wide swings—mostly due to wars and the monetary experiment of playing card money. The creation of this index lays the foundation of the next component. The second component constructs a standardized real wage series in the form of welfare ratios (a consumption basket divided by nominal wage rate multiplied by length of work year) to compare Canada with France, England and Colonial America. Two measures are derived. The first relies on a “bare bones” definition of consumption with a large share of land-intensive goods. This measure indicates that Canada was poorer than England and Colonial America and not appreciably richer than France. However, this measure overestimates the relative position of Canada to the Old World because of the strong presence of land-intensive goods. A second measure is created using a “respectable” definition of consumption in which the basket includes a larger share of manufactured goods and capital-intensive goods. This second basket better reflects differences in living standards since the abundance of land in Canada (and Colonial America) made it easy to achieve bare subsistence, but the scarcity of capital and skilled labor made the consumption of luxuries and manufactured goods (clothing, lighting, imported goods) highly expensive. With this measure, the advantage of New France over France evaporates and turns slightly negative. In comparison with Britain and Colonial America, the gap widens appreciably. This element is the most important for future research. By showing a reversal because of a shift to a different type of basket, it shows that Old World and New World comparisons are very sensitive to how we measure the cost of living. Furthermore, there are no sustained improvements in living standards over the period regardless of the measure used. Gaps in living standards observed later in the nineteenth century existed as far back as the seventeenth century. In a wider American perspective that includes the Spanish colonies, Canada fares better. The third component computes a new series for Gross Domestic Product (GDP). This is to avoid problems associated with using real wages in the form of welfare ratios which assume a constant labor supply. This assumption is hard to defend in the case of Colonial Canada as there were many signs of increasing industriousness during the eighteenth and nineteenth centuries. The GDP series suggest no long-run trend in living standards (from 1688 to circa 1765). The long peace era of 1713 to 1740 was marked by modest economic growth which offset a steady decline that had started in 1688, but by 1760 (as a result of constant warfare) living standards had sunk below their 1688 levels. These developments are accompanied by observations that suggest that other indicators of living standard declined. The flat-lining of incomes is accompanied by substantial increases in the amount of time worked, rising mortality and rising infant mortality. In addition, comparisons of incomes with the American colonies confirm the results obtained with wages— Canada was considerably poorer. At the end, a long conclusion is provides an exploratory discussion of why Canada would have diverged early on. In structural terms, it is argued that the French colony was plagued by the problem of a small population which prohibited the existence of scale effects. In combination with the fact that it was dispersed throughout the territory, the small population of New France limited the scope for specialization and economies of scale. However, this problem was in part created, and in part aggravated, by institutional factors like seigneurial tenure. The colonial origins of French America’s divergence from the rest of North America are thus partly institutional

    26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

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    This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

    The Seeds of Divergence: The Economy of French North America, 1688 to 1760

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    Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

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    Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

    The use of conducting polymer sensors for environmental monitoring

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    This thesis details the development of conducting polymer (CP) sensors, and associated devices for monitoring chemical species of environmental significance. A key aspect of this work was the fabrication and testing of novel CP gas sensors, based on inexpensive polymer substrates with screen-printed carbon electrodes. These devices were used in electronic nose systems for the identification and discrimination of organic vapours, and on a small autonomous robot to detect, track and locate the source of ammonia vapour plumes. The possibility of modifying chemically deposited Polypyrrole (PPy) thin films post-polymerisation using solution based anion exchange methods was evaluated, in an attempt to alter chemical selectivity whilst retaining the sensitivity of such devices. Approaches to reducing the humidity response of PPy gas sensors, a significant interferant when sensing many sample matrices, were also examined with the view to developing vapour detection systems for organic volatiles in water. A comprehensive study of the electrochemistry and spectral properties of a water soluble conducting polymer, Polymethoxyaniline sulfonate (PMAS), and the effect of molecular weight on these properties was undertaken. This work was carried out in order to better understand the mechanism of interaction between PMAS and the microorganism Listeria Monocytogenes, which is under development at IPRI as a detection system for this species

    The use of conducting polymer sensors for environmental monitoring

    Get PDF
    This thesis details the development of conducting polymer (CP) sensors, and associated devices for monitoring chemical species of environmental significance. A key aspect of this work was the fabrication and testing of novel CP gas sensors, based on inexpensive polymer substrates with screen-printed carbon electrodes. These devices were used in electronic nose systems for the identification and discrimination of organic vapours, and on a small autonomous robot to detect, track and locate the source of ammonia vapour plumes. The possibility of modifying chemically deposited Polypyrrole (PPy) thin films post-polymerisation using solution based anion exchange methods was evaluated, in an attempt to alter chemical selectivity whilst retaining the sensitivity of such devices. Approaches to reducing the humidity response of PPy gas sensors, a significant interferant when sensing many sample matrices, were also examined with the view to developing vapour detection systems for organic volatiles in water. A comprehensive study of the electrochemistry and spectral properties of a water soluble conducting polymer, Polymethoxyaniline sulfonate (PMAS), and the effect of molecular weight on these properties was undertaken. This work was carried out in order to better understand the mechanism of interaction between PMAS and the microorganism Listeria Monocytogenes, which is under development at IPRI as a detection system for this species
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