257 research outputs found

    Paraunitary oversampled filter bank design for channel coding

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    Oversampled filter banks (OSFBs) have been considered for channel coding, since their redundancy can be utilised to permit the detection and correction of channel errors. In this paper, we propose an OSFB-based channel coder for a correlated additive Gaussian noise channel, of which the noise covariance matrix is assumed to be known. Based on a suitable factorisation of this matrix, we develop a design for the decoder's synthesis filter bank in order to minimise the noise power in the decoded signal, subject to admitting perfect reconstruction through paraunitarity of the filter bank. We demonstrate that this approach can lead to a significant reduction of the noise interference by exploiting both the correlation of the channel and the redundancy of the filter banks. Simulation results providing some insight into these mechanisms are provided

    Il était une fois un match de foot:L'événement sportif comme objet de narration

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    L’analyse des temps de la narration n’est pas chose nouvelle. Souvent, ce sont les narrations orales ‘de tous les jours’ qui ont prĂ©occupĂ© les linguistes (Labov & Waletzky 1967, Bres 1994). Mais qu’en est-il de l’usage des temps dans les narrations Ă©crites telles qu’on les trouve dans la presse sportive? On se fondera ici sur un corpus d’articles du 1er juillet 2002, tirĂ©s de la presse francophone (parisienne, rĂ©gionale, belge et algĂ©rienne) et consacrĂ©s Ă  la finale de la Coupe du Monde de football (Labeau 2002b). A quels temps a-t-on recours pour narrer ces exploits sportifs ? Le passĂ© simple a-t-il toujours sa place dans ce genre « Ă©pique », ou s’est-il vu supplanter par d’autres formes telles le passĂ© composĂ©, le prĂ©sent ou l’imparfait de narration
 ? (Engel 1990) Nous allons nous concentrer sur deux aspects de l’emploi des temps. D’une part, la presse sportive constitue-t-elle un sous-genre distinct ? D’autre part, des diffĂ©rences rĂ©gionales apparaissent-elles ? Nous tenterons de voir si les approches textuelles se reflĂštent dans l’emploi des temps des narrations Ă©tudiĂ©es. Termes clefs Narration - presse sportive – temps - presse rĂ©gionale – presse francophone - genr

    A novel heavy-fermion state in CaCu_3Ru_4O12

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    We have measured susceptibility, specific heat, resistivity, and thermopower of CaCu3_3Ti4−x_{4-x}Rux_xO12_{12} and CaCu3−y_{3-y}Mny_yRu4_4O12_{12}, and have found that CaCu3_3Ru4_4O12_{12} can be regarded as a heavy-fermion oxide in d-electron systems. The Kondo temperature is near 200 K, and the susceptibility (1.4×10−3\times10^{-3} emu/Cu mol) and the electron specific heat coefficient (28 mJ/Cu molK2^2) are moderately enhanced. The resistivity is proportional to T2T^2 at low temperatures, and satisfies the Kadowaki-Woods relation. The heavy-fermion state comes from the interaction between the localized moment of Cu 3d and the conduction electron of Ru 4d. An insulator-metal transition occurs between x=1.5x=1.5 and 4 in CaCu3_3Ti4−x_{4-x}Rux_xO12_{12}, which can be regarded as a transition from magnetic insulator to heavy-fermion metal.Comment: 4 pages, 5 figures, submitted to J. Phys. Soc. Jp

    A model-based extension to HiP-HOPS for dynamic fault propagation studies

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    HiP-HOPS is a model-based approach for assessing the dependability of safety-critical systems. The method combines models, logic, probabilities and nature-inspired algorithms to provide advanced capabilities for design optimisation, requirement allocation and safety argument generation. To deal with dynamic systems, HiP-HOPS has introduced temporal operators and a temporal logic to represent and assess event sequences in component failure modelling. Although this approach has been shown to work, it is not entirely consistent with the way designers tend to express operational dynamics in models which show mode and state sequences. To align HiP-HOPS better with typical design techniques, in this paper, we extend the method with the ability to explicitly consider different modes of operation. With this added capability HiP-HOPS can create and analyse temporal fault trees from architectural models of a system which are augmented with mode information

    Heavy-Mass Behavior of Ordered Perovskites ACu3Ru4O12 (A = Na, Ca, La)

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    We synthesized ACu3Ru4O12 (A = Na, Na0.5Ca0.5, Ca, Ca0.5La0.5, La) and measured their DC magnetization, AC susceptibility, specific heat, and resistivity, in order to investigate the effects of the hetero-valent substitution. A broad peak in the DC magnetization around 200 K was observed only in CaCu3Ru4O12, suggesting the Kondo effect due to localized Cu2+ ions. However, the electronic specific heat coefficients exhibit large values not only for CaCu3Ru4O12 but also for all the other samples. Moreover, the Wilson ratio and the Kadowaki-Woods ratio of our samples are all similar to the values of other heavy-fermion compounds. These results question the Kondo effect as the dominant origin of the mass enhancement, and rather indicate the importance of correlations among itinerant Ru electrons.Comment: 6 pages, 6 figures, to be published in J. Phys. Soc. Jp

    Prevalence of skin pressure injury in critical care patients in the UK: results of a single-day point prevalence evaluation in adult critically ill patients.

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    OBJECTIVES: Hospital-acquired pressure injuries (PIs) are a source of morbidity and mortality, and many are potentially preventable. DESIGN: This study prospectively evaluated the prevalence and the associated factors of PIs in adult critical care patients admitted to intensive care units (ICU) in the UK. SETTING: This service evaluation was part of a larger, international, single-day point prevalence study of PIs in adult ICU patients. Training was provided to healthcare givers using an electronic platform to ensure standardised recognition and staging of PIs across all sites. PARTICIPANTS: The characteristics of the ICUs were recorded before the survey; deidentified patient data were collected using a case report form and uploaded onto a secure online platform. PRIMARY AND SECONDARY OUTCOME MEASURES: Factors associated with ICU-acquired PIs in the UK were analysed descriptively and using mixed multiple logistic regression analysis. RESULTS: Data from 1312 adult patients admitted to 94 UK ICUs were collected. The proportion of individuals with at least one PI was 16% (211 out of 1312 patients), of whom 8.8% (n=115/1312) acquired one or more PIs in the ICU and 7.3% (n=96/1312) prior to ICU admission. The total number of PIs was 311, of which 148 (47.6%) were acquired in the ICU. The location of majority of these PIs was the sacral area, followed by the heels. Braden score and prior length of ICU stay were associated with PI development. CONCLUSIONS: The prevalence and the stage of severity of PIs were generally low in adult critically ill patients admitted to participating UK ICUs during the study period. However, PIs are a problem in an important minority of patients. Lower Braden score and longer length of ICU stay were associated with the development of injuries; most ICUs assess risk using tools which do not account for this. TRIAL REGISTRATION NUMBER: NCT03270345
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