239 research outputs found

    Performance Improvement in Passive Backscatter Based RFID System with Low DCR Modulations

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    This paper presents application of the low Duty Cycle Ratio (DCR) modulations: isochronous Digital Pulse Position Modulation (DPPM) and anisochronous Digital Pulse Interval Modulation (DPIM) in backscatter based passive RFID communication system. The proposed modulations are compared to commonly used Amplitude Shift Keying (ASK) modulation. Low DCR modulations are customized for data transmission through inductively coupled link between reader and the tag operating at frequency of 13.56 MHz. The RFID system is mathematically formulated and the performances of the tag are evaluated for each modulation. Observed parameters are modulation depth of backscattered signal, voltage-current characteristics of tag rectifier circuit and ripple of rectifier output voltage. The application of proposed low DCR modulation techniques improves the performance of the RFID system by up to 250%

    Fade Depth Prediction Using Human Presence for Real Life WSN Deployment

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    Current problem in real life WSN deployment is determining fade depth in indoor propagation scenario for link power budget analysis using (fade margin parameter). Due to the fact that human presence impacts the performance of wireless networks, this paper proposes a statistical approach for shadow fading prediction using various real life parameters. Considered parameters within this paper include statistically mapped human presence and the number of people through time compared to the received signal strength. This paper proposes an empirical model fade depth prediction model derived from a comprehensive set of measured data in indoor propagation scenario. It is shown that the measured fade depth has high correlations with the number of people in non-line-of-sight condition, giving a solid foundation for the fade depth prediction model. In line-of-sight conditions this correlations is significantly lower. By using the proposed model in real life deployment scenarios of WSNs, the data loss and power consumption can be reduced by the means of intelligently planning and designing Wireless Sensor Network

    Low-energy electronic structure in Y1-xCaxBa2Cu3O7-y comparison of t ime-resolved optical spectroscopy, NMR, neutron and tunneling data

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    Time-resolved optical measurements give information on the quasiparticle relaxation dynamics in YBCO, from which the evolution of the gap with doping and temperature can be systematically deduced. In this paper these optical charge-channel `pseudogap' data are compared with the `pseudogap' obtained from the NMR Knight shift Ks, spin polarized neutron scattering (SPNS) and single particle tunneling measurements. A simple energy level diagram is proposed to explain the different `gap' magnitudes observed by different spectroscopies in Y1-xCaxBa2Cu3O7-y, whereby the spin gap Delta_s in NMR and SPNS corresponds to a triplet local pair state, while Delta_p in the charge excitation spectrum corresponds to the pair dissociation energy. At optimum doping and in the overdoped state, an additional T-dependent gap becomes evident, which closes at T_c, suggesting a cross-over to a more conventional BCS-like superconductivity scenario.Comment: 9 pages, 4 figures. Presented in HTS99, Miami, January 9

    Similarity in Visual Word Recognition: The Effect of Syllabic Neighborood in French

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    Hypoglycaemic events in patients with type 2 diabetes in the United Kingdom: associations with patient-reported outcomes and self-reported HbA1c

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    BACKGROUND: One possible barrier to effective diabetes self-management is hypoglycaemia associated with diabetes medication. The current study was conducted to characterize hypoglycaemic events among UK patients with type 2 diabetes (T2D) treated with antihyperglycaemic medications, and assess the relationship between experience of hypoglycaemic events and health outcomes, including glycaemic control, health-related quality of life, impairment to work and non-work activities, treatment satisfaction, adherence to treatment, fear of hypoglycaemia, and healthcare resource use. METHODS: An online survey of 1,329 T2D patients in UK drawn from an opt-in survey panel was conducted in February of 2012 with monthly follow-up questionnaires for five months. Measures included self-reported HbA1c, EQ-5D, Work Productivity and Activity Impairment questionnaire, Diabetes Medication Satisfaction Tool, Morisky medication adherence scale, the Hypoglycaemia Fear Survey (revised), and self-reported healthcare resource use. Comparisons were conducted using t-tests and chi-square tests for continuous and categorical variables, respectively. RESULTS: Baseline comparisons showed that worse HbA1c, greater diabetes-related healthcare resource use, greater fear of hypoglycaemia, and impaired health outcomes were associated with experience of hypoglycaemia in the four weeks prior to baseline. Longitudinal results were similar in direction but differences on few measures were significant. CONCLUSIONS: In real-world UK T2D patients, hypoglycaemia is associated with worse self-reported glycaemic control, behaviours that contribute to worse glycaemic control, and impairment in patient-reported outcomes

    Practical reasoning in political discourse: The UK government's response to the economic crisis in the 2008 Pre-Budget Report

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    This article focuses on practical reasoning in political discourse and argues for a better integration of argumentation theory with critical discourse analysis (CDA). Political discourse and its specific genres (for example, deliberation) primarily involve forms of practical reasoning, typically oriented towards finding solutions to problems and deciding on future courses of action. Practical reasoning is a form of inference from cognitive and motivational premises: from what we believe (about the situation or about means—end relations) and what we want or desire (our goals and values), leading to a normative judgement (and often a decision) concerning action. We offer an analysis of the main argument in the UK government’s 2008 Pre-Budget Report (HM Treasury, 2008) and suggest how a critical evaluation of the argument from the perspective of a normative theory of argumentation (particularly the informal logic developed by Douglas Walton) can provide the basis for an evaluation in terms of characteristic CDA concerns. We are advancing this analysis as a contribution to CDA, aimed at increasing the rigour and systematicity of its analyses of political discourse, and as a contribution to the normative concerns of critical social science

    An exploration of the current knowledge on young people who kill: a systematic review

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    This exploratory systematic review assessed the quality of primary studies on young people who kill and synthesised the findings regarding the characteristics of these offenders. An electronic search yielded 12,717 hits of papers published between 1989 and 2012. Of these, 8,395 duplicates, 3,787 irrelevant hits, and 527 publications not meeting the inclusion criteria of the review were excluded (15 publications were added after searching the grey literature), leaving 23 good quality studies. From these, a further seven were removed due to their small sample size (i.e., n < 30), leaving a total of 16 studies reviewed in detail. A search update was carried out on 2 February 2014 and no further studies meeting the inclusion criteria were found. The results indicate that juvenile homicide offenders are a heterogeneous group and the risk factors for juvenile homicide are cumulative and evolve through life. The findings are mixed, but ten risk factors are identified which appear to be consistent for offenders across the studies reviewed. The limitations of the current review are highlighted and recommendations for future research are outlined, with particular consideration given to improving the quality of the literature in this field

    A Study of the Day - Night Effect for the Super - Kamiokande Detector: I. Time Averaged Solar Neutrino Survival Probability

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    This is the first of two articles aimed at providing comprehensive predictions for the day-night (D-N) effect for the Super-Kamiokande detector in the case of the MSW \nu_e \to \numt transition solution of the solar neutrino problem. The one-year averaged probability of survival of the solar \nue crossing the Earth mantle, the core, the inner 2/3 of the core, and the (core + mantle) is calculated with high precision (better than 1%) using the elliptical orbit approximation (EOA) to describe the Earth motion around the Sun. Results for the survival probability in the indicated cases are obtained for a large set of values of the MSW transition parameters Δm2\Delta m^2 and sin22θVsin^22\theta_{V} from the ``conservative'' regions of the MSW solution, derived by taking into account possible relatively large uncertainties in the values of the 8^{8}B and 7^{7}Be neutrino fluxes. Our results show that the one-year averaged D-N asymmetry in the νe\nu_e survival probability for neutrinos crossing the Earth core can be, in the case of sin22θV≤0.13sin^22 \theta_{V} \leq 0.13, larger than the asymmetry in the probability for (only mantle crossing + core crossing) neutrinos by a factor of up to six. The enhancement is larger in the case of neutrinos crossing the inner 2/3 of the core. This indicates that the Super-Kamiokande experiment might be able to test the sin22θV≤0.01sin^22\theta_{V} \leq 0.01 region of the MSW solution of the solar neutrino problem by performing selective D-N asymmetry measurements.Comment: LaTeX2e - 18 Text Pages + 21 figures = 39 Pages. - Figures in PS + text file sk1b14.tex requires two auxiliary files (included
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