12,540 research outputs found

    On large deviation regimes for random media models

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    The focus of this article is on the different behavior of large deviations of random subadditive functionals above the mean versus large deviations below the mean in two random media models. We consider the point-to-point first passage percolation time ana_n on Zd\mathbb{Z}^d and a last passage percolation time ZnZ_n. For these functionals, we have limnann=ν\lim_{n\to\infty}\frac{a_n}{n}=\nu and limnZnn=μ\lim_{n\to\infty}\frac{Z_n}{n}=\mu. Typically, the large deviations for such functionals exhibits a strong asymmetry, large deviations above the limiting value are radically different from large deviations below this quantity. We develop robust techniques to quantify and explain the differences.Comment: Published in at http://dx.doi.org/10.1214/08-AAP535 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    What are people's responses to thermal discomfort? Sensing clothing and activity levels using senseCam

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    Recent international agreements on reducing energy consumption have led to a series of interventions in residential buildings, from modifying the building fabric to upgrading operating systems. To date, these attempts have met with limited success. One reason for this has been identified as the ‘rebound effect’, where the occupants’ respond to their home thermal environment change in unexpected ways after interventions. Often people decide to turn up the heating, to leave it on for longer, or to increase the average spatial temperature by heating more rooms. Although much of the research on heating patterns in dwellings has focused on identifying methods to predict and to assess thermal sensation, less is understood about the way occupants form their responses. Research presented in this paper focuses on mapping householders thermal discomfort responses. Empirical methods, drawn from the social and cognitive sciences, were used in a several studies, which monitored a small sample of UK households during winter of 2010. One of the tools used, the SenseCam, facilitates an automatic electronic diary collection by logging occupants’ responses in a systematic approach.SenseCam results enabled the mapping of participants’ activities in their home, in particular the estimation of clothing and activity level throughout the record period. The preliminary monitoring results show that different householders are interacting with their home thermal comfort systems in very different ways, and that their responses diverge from the current predictive models. Further analysisexamines the factors influencing responses to thermal discomfort and thereby energy consumption of individual in dwellings

    The role of environmental and personal variables in influencing thermal comfort indices used in building simulation

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    The need to identify variables, which influence human behaviour, has become one of the priorities in the quest to reduce energy demand. Environmental and personal variables, as set out in the thermal comfort models, have long been associated with people’s behaviour by predicting their state of thermal comfort or rather discomfort. The aim of this paper is to explore and to report on the influences of these variables on thermal discomfort indices used in building simulation models. Surprisingly, the results of the sensitivity analysis show that different indices are most sensitive to different variables

    Understanding the dynamics of residential energy consumption in the UK: mapping occupants thermal discomfort responses

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    Attempts to reduce the energy consumed in UK homes have had limited success. One reason for this has been identified as the ‘rebound effect’, where the occupants’ responses to their thermal environment change in unexpected ways after interventions. Although much of the research on heating patterns in dwellings has focused on achieving thermal comfort, less is understood about the way occupants form their responses. Using empirical methods drawn from social and cognitive sciences, this paper proposes a set of tools, implemented in a pilot study, carried out on a small sample of UK households during winter of 2010. One of the tools used, the SenseCam facilitates an electronic diary collection by logging occupants’ responses in a systematic approach. Preliminary monitoring works show that different householders are interacting with their home thermal comfort systems in very different ways, and that their responses diverge from the current predictive models. These results suggest that future samples may be examined to gain further insights about the development of ideas in this field

    Subwavelength position sensing using nonlinear feedback and wave chaos

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    We demonstrate a position-sensing technique that relies on the inherent sensitivity of chaos, where we illuminate a subwavelength object with a complex structured radio-frequency field generated using wave chaos and a nonlinear feedback loop. We operate the system in a quasi-periodic state and analyze changes in the frequency content of the scalar voltage signal in the feedback loop. This allows us to extract the object's position with a one-dimensional resolution of ~\lambda/10,000 and a two-dimensional resolution of ~\lambda/300, where \lambda\ is the shortest wavelength of the illuminating source.Comment: 4 pages, 4 figure

    Narrative desire and historical reparations: Three contemporary British authors

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    British novelists since Walter Scott have exhibited an interest in history, but this discursive affinity has transformed itself into a veritable obsession in the fiction of the last two decades. Indeed, a concern with and distrust of history and historiographic projects is often hailed as a defining characteristic of postmodernism. And while writers of new historical novels cannot be said to form a movement as such, the predominance of such texts reveals the presence of communal concerns, and a readily identifiable strain of literary production that addresses the circulation of mutual symptoms, beliefs, and anxieties as a response to living in this particular moment in history. Adopting and adapting the theories of Hayden White and Peter Brooks, I highlight various types of narrative desire that drive both narrators and readers in their emplotment of history. Examining three representative novels---A. S. Byatt\u27s Possession: A Romance, Ian McEwan\u27s Black Dogs, and Salman Rushdie\u27s Midnight\u27s Children---this study explores the communal logic and impulse that identifies both reading and constructing narratives as purposeful gestures in coming to terms with our present and future. Each novel attempts to control the ambiguities of history and our ability truly to know it by allowing historical fact and fiction to merge, overlap, and create a new whole. These novels also reflect a number of cultural anxieties about the various narratives that have been constructed to explain the past: Byatt contests the postmodern dismissal of Victorian ideologies in the working through of narratives; McEwan requires a reassessment of the Enlightenment narrative in the face of the collective trauma of the twentieth century\u27s violent history; and Rushdie re-narrates recent Indian history in order to find an issue out of the impasse of fundamentalist and monolithic conceptions of national identity. These novelists, in different ways, employ what has become known as postmodern artifice, sometimes as a way to reject the notion of historical construction, sometimes to advocate it, but always to bring us closer to what they believe are significant values and truths
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