206 research outputs found

    Sound Recognition of Historical Visibility: The Radio Preservation Task Force of the Library of Congress: Introduction

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    This issue of Journal of Radio & Audio Media serves as a gesture toward increasing attention to many untold cultural sound histories. The “question” of radio preservation, we’re just coming to realize, closely equates to our responsibility to identify gaps within our historical record, as those gaps are delineated along race, class, orientation, and gendered lines. Sound preservation turns out to be one strategy for how to reconcile failures of recognition. It’s widely accepted that a historian must not project a different meaning upon historical materials than its author intended. Yet at the same time historians might now play the role of advocates, by increasing representation through digital preservation. Sound history is one of the last frontiers to build paths of visibility among scattered records. The Radio Preservation Task Force (RPTF) of the National Recording Preservation Board of the Library of Congress represents one such project. National in scope but local in focus, the RPTF is currently in the process of constructing several interconnected initiatives that will culminate in a detailed mapping of the cultural history of radio, so as to reveal previously hidden experiences, events, and perspectives

    Synthetic approach to the Quillen model structure on topological spaces

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    We provide an axiomatic treatment of Quillen's construction of the model structure on topological spaces to make it applicable to a wider range of settings, including Δ\Delta-generated spaces and pseudotopological spaces. We use this axiomatization to construct a model structure on the category of locales.Comment: 31 pages; comments welcom

    Speeding up Permutation Testing in Neuroimaging

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    Multiple hypothesis testing is a significant problem in nearly all neuroimaging studies. In order to correct for this phenomena, we require a reliable estimate of the Family-Wise Error Rate (FWER). The well known Bonferroni correction method, while simple to implement, is quite conservative, and can substantially under-power a study because it ignores dependencies between test statistics. Permutation testing, on the other hand, is an exact, non-parametric method of estimating the FWER for a given α\alpha-threshold, but for acceptably low thresholds the computational burden can be prohibitive. In this paper, we show that permutation testing in fact amounts to populating the columns of a very large matrix P{\bf P}. By analyzing the spectrum of this matrix, under certain conditions, we see that P{\bf P} has a low-rank plus a low-variance residual decomposition which makes it suitable for highly sub--sampled --- on the order of 0.5%0.5\% --- matrix completion methods. Based on this observation, we propose a novel permutation testing methodology which offers a large speedup, without sacrificing the fidelity of the estimated FWER. Our evaluations on four different neuroimaging datasets show that a computational speedup factor of roughly 50×50\times can be achieved while recovering the FWER distribution up to very high accuracy. Further, we show that the estimated α\alpha-threshold is also recovered faithfully, and is stable.Comment: NIPS 1

    Aerodynamic forces on generic buildings subject to transient, downburst-type winds

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    AbstractHaving been identified as the cause of design load winds in many parts of the world, transient winds such as gust fronts and thunderstorm downbursts have been increasingly researched over recent years. The difficulties in simulating the flow structure of downbursts in the laboratory, particularly their rapid radial acceleration and associated ring vortices, have complicated measuring wind loads on structures subject to these conditions. The University of Birmingham Transient Wind Simulator (UoB-TWS, a 1m diameter impinging jet with aperture control) has been used to simulate the transient aspects of downburst-like flow, allowing the pressure distributions they create over cube and portal framed structures to be measured for the first time, at model-scale (1:1600). Analysis of the velocity and pressure fields show that the simulator is capable of creating velocity fields which are similar to those observed in nature. Development of the ring vortex is demonstrated through phase-plot analysis. Two methods of calculating the turbulence intensity of the unsteady flow field have been used, giving mean values of between 3% and 10% depending on the method. Force coefficient time series have been estimated with the buildings angled at 0°, 45° and 90° to the radial wind direction. These are presented along with the instantaneous pressure coefficient distribution at the time of maximum roof suction. This novel research also highlights the difficulties of undertaking transient flow at model scale and drawing conclusions which are applicable to full-scale, i.e., where no two events are the same

    EV’s Leading in China, Ford is a Few Cars Behind

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    As the world is looking at sustainable energy sources, electric vehicles are likely to be a big part of the perceived future. China has 18.47% of the world’s population, is one of the highest emitters of carbon dioxide, and is the world’s largest market for electric vehicles (Country Meters). China’s GDP was USD 13.608 trillion in 2018 and is expected to increase substantially in coming years (Wang, 2019). With 25 million vehicles sold in 2019, China’s automobile market is the biggest in the world. With that, China accounts for 27.52% of the world’s CO2 emissions (Statista). To decrease that number, China stated in 2019 their goal was to have 60% of all automobiles sold in 2035 to run on electric motors (Tian, 2019). With car sales in China declining rapidly over the past 3 years, automobile companies are looking for a way to develop a sustainable competitive advantage. Ford Motor Company, a 156billiongloballeader,hasbeenstrugglingtocompeteinChinaandisnowlookingtotheelectricvehiclemarketasawaytoexpand.However,China’sEVmarketishypercompetitivewithover400domesticEVmanufacturers,includingsomemultinationalslikeGeneralMotors.Todifferentiatethemselvesfromthecompetition,FordannouncedplansofbuildingfacilitiesthatwillspecializeincreatingtechnologyfortheirEV’s.SYNC+isapopulartechnologicaloptionavailabletoenhancetheconsumersexperience(MediaFord,2019).However,investmentintechnologycouldraisethepricesoftheirvehicles.WithannualincomeinChinaatabout82,413yuan(156 billion global leader, has been struggling to compete in China and is now looking to the electric vehicle market as a way to expand. However, China’s EV market is hypercompetitive with over 400 domestic EV manufacturers, including some multinationals like General Motors. To differentiate themselves from the competition, Ford announced plans of building facilities that will specialize in creating technology for their EV’s. SYNC+ is a popular technological option available to enhance the consumers experience (Media Ford, 2019). However, investment in technology could raise the prices of their vehicles. With annual income in China at about 82,413 yuan (11,727 USD), raising prices may not be an option for Ford (Statista). This case study discusses the many challenges that Ford faces in China and how it needs to change its marketing mix in order to succeed there. Keywords: Ford, China, Electric Vehicles, Pollution, Environment, Automobiles, Case Study, Emerging Markets, International marketin

    A epidemiologia dos "edifĂ­cios doentes"

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    O meio ambiente interno dos edifícios modernos, especialmente aqueles designados para uso comercial e administrativo, constitui nicho ecológico com seu próprio meio bioquímico, fauna e flora. Sofisticados métodos de construção e os novos materiais e equipamentos necessários para manter o meio ambiente interno destas estruturas fechadas produzem grande número de sub-produtos químicos e permitem o desenvolvimento de diversos microorganismos. Estes edifícios, por serem hermeticamente fechados, apresentam um dilema quanto a regulagem da umidade e temperatura do ar que circula pelos duetos, uma vez que diferentes espécies de microoganismos se desenvolvem em diferentes combinações de umidade e temperatura. Se o meio ambiente interno dos edifícios fechados não for mantido de forma adequada, pode se tornar nocivo para a saúde dos seus ocupantes. Nessas condições, edifícios fechados, são chamados de "Edifícios Doentes". Apresenta-se uma revisão da epidemiologia das doenças ocasionadas por esses edifícios fechados, etiologia das doenças dos ocupantes, origens das substâncias tóxicas e métodos possíveis para manter um ambiente interno seguro.The indoor environment of modern buildings, especially those designed for commercial and administrative purposes, constitutes a unique ecological niche with its own biochemical environment, fauna and flora. Sophisticated construction methods and the new materials and machinery required to maintain the indoor environment of these enclosed structures produce a large number of chemical by-products and permit the growth of many different microorganisms. Because modern office buildings are sealed, the regulation of humidification and temperature of ducted air presents a dilemma, since difference species of microorganisms flourish at different combinations of humidity and temperature. If the indoor environment of modern office buildings is not properly maintened, the environment may become harmful to its occupants' health. Such buildings are classified as "Sick Buildings". A review of the epidemiology of building illness is presented. The etiology of occupant illnesses, sources of toxic substances, and possible methods of maintaining a safe indoor environment are described

    Aerodynamic forces on the roofs of low-, mid- and high-rise buildings subject to transient winds

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    AbstractTransient winds, such as thunderstorm downbursts, are the cause of design-load wind speeds in many countries. An understanding of the loading experienced by buildings during a downburst is therefore important to allow well designed and engineered buildings to be constructed. In contrast to boundary layer winds, the maximum wind speed in thunderstorm downbursts occurs as low as zm=30m above the ground, within the range of heights of man-made structures, suggesting that the wind loading will be dependent on the building eaves height relative to zm. In a novel set of experiments, the University of Birmingham Transient Wind Simulator (a 1m diameter impinging jet with aperture control) has been used to simulate a downburst striking buildings of different heights, ranging from below to above zm. Two forms of building have been used – a square-plan, flat-roofed structure, and a rectangular, portal-frame – at three angles (0°, 45° and 90°) relative to the radial wind direction. Pressure coefficients have been calculated (using eaves height velocity) over the roofs of these buildings, and are shown to be of greatest magnitude when the roof is above the region of maximum outflow velocity, with the exception of windward edges perpendicular to the flow, when they are generally greatest for the lowest building heights

    A randomised clinical trial of a comprehensive exercise program for chronic whiplash: trial protocol

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    Background: Whiplash is the most common injury following a motor vehicle accident. Approximately 60% of people suffer persistent pain and disability six months post injury. Two forms of exercise; specific motor relearning exercises and graded activity, have been found to be effective treatments for this condition. Although the effect sizes for these exercise programs, individually, are modest, pilot data suggest much larger effects on pain and disability are achieved when these two treatments are combined. The aim of this study is to investigate the effectiveness and cost-effectiveness of this comprehensive exercise approach for chronic whiplash
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