5,099 research outputs found

    Haptic dancing: human performance at haptic decoding with a vocabulary

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    The inspiration for this study is the observation that swing dancing involves coordination of actions between two humans that can be accomplished by pure haptic signaling. This study implements a leader-follower dance to be executed between a human and a PHANToM haptic device. The data demonstrates that the participants' understanding of the motion as a random sequence of known moves informs their following, making this vocabulary-based interaction fundamentally different from closed loop pursuit tracking. This robot leader does not respond to the follower's movement other than to display error from a nominal path. This work is the first step in an investigation of the successful haptic coordination between dancers, which will inform a subsequent design of a truly interactive robot leader

    Human-human haptic collaboration in cyclical Fitts' tasks

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    Understanding how humans assist each other in haptic interaction teams could lead to improved robotic aids to solo human dextrous manipulation. Inspired by experiments reported in Reed et al. (2004), which suggested two-person haptically interacting teams could achieve a lower movement time (MT) than individuals for discrete aiming movements of specified accuracy, we report that two-person teams (dyads) can also achieve lower MT for cyclical, continuous aiming movements. We propose a model, called endpoint compromise, for how the intended endpoints of both subjects' motion combine during haptic interaction; it predicts a ratio of /spl radic/2 between slopes of MT fits for individuals and dyads. This slope ratio prediction is supported by our data

    A qualitative exploration of consumers’ perceived impacts, behavioural reactions, and future reflections of the EU Tobacco Products Directive (2017) as applied to electronic cigarettes

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    Background: Electronic cigarette regulations included in the Tobacco Products Directive (TPD), Article 20, implemented in Europe by May 2017, aimed to improve safety for e-cigarette consumers, and prevent uptake among non-smokers, particularly young people. Before implementation, there were significant concerns from consumers, industry, and some in the scientific community about the potential negative impact of the TPD on people using e-cigarettes to stay stopped from smoking. To date, there is limited evidence on how the TPD has affected consumers. This study aimed to add insight into how consumers perceived and experienced the regulations. Methods: Qualitative data, collected between March 2018 and March 2019, relating to participant views of the TPD were extracted from 160 interviews/extended surveys of e-cigarette consumers as part of a wider study into e-cigarette use trajectories (ECtra study). Data were thematically analysed. Results: Awareness of the TPD amongst consumers was not universal. Participants’ smoking behaviour did not appear to be influenced by the legislation. Participants were reassured by manufacturing regulations and requirements for ingredients labels. Participants responded negatively to changes perceived to cause inconvenience and extra plastic waste. The product restrictions prompted some participants to purchase non-compliant products illegally, potentially putting their safety at risk. Conclusions: E-cigarette regulation should focus on ensuring product safety. Raising awareness of the TPD amongst consumers and smokers could be beneficial

    Optical Detection and Analysis of Pictor A's Jet

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    New images from the Hubble Space Telescope of the FRII radio galaxy Pictor A reveal a number of jet knot candidates which coincide with previously detected radio and x-ray knots. Previous observations in x-ray and radio bands show the entire jet to be 1.9' long, with interesting variability, but an optical component was previously unknown. The discovered optical component is faint, and knot candidates must be teased out from a bright host galaxy. Using three broadband filters, we extract knot fluxes and upper-bounds on the flux for multiple knot candidates at wavelengths of 1600nm, 814nm and 475nm. We find that the data suggest that localized particle re-accleration events followed by synchrotron emission could explain the observed knot candidates, but those electrons could not supply enough x-ray flux to match prior observations. Our data provide key evidence suggesting a second, higher energy electron population which was previously hypothesized, but could not be confirmed.Comment: B.Sc. Thesis, MIT; 78 pages, 20 figure

    Enhanced Momentum Feedback from Clustered Supernovae

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    Young stars typically form in star clusters, so the supernovae (SNe) they produce are clustered in space and time. This clustering of SNe may alter the momentum per SN deposited in the interstellar medium (ISM) by affecting the local ISM density, which in turn affects the cooling rate. We study the effect of multiple SNe using idealized 1D hydrodynamic simulations which explore a large parameter space of the number of SNe, and the background gas density and metallicity. The results are provided as a table and an analytic fitting formula. We find that for clusters with up to ~100 SNe the asymptotic momentum scales super-linearly with the number of SNe, resulting in a momentum per SN that can be an order of magnitude larger than for a single SN, with a maximum efficiency for clusters with 10-100 SNe. We argue that additional physical processes not included in our simulations -- self-gravity, breakout from a galactic disk, and galactic shear -- can slightly reduce the momentum enhancement from clustering, but the average momentum per SN still remains a factor of 4 larger than the isolated SN value when averaged over a realistic cluster mass function for a star-forming galaxy. We conclude with a discussion of the possible role of mixing between hot and cold gas, induced by multi-dimensional instabilities or preexisting density variations, as a limiting factor in the buildup of momentum by clustered SNe, and suggest future numerical experiments to explore these effects.Comment: 19 pages, 26 figures, revised to reflect accepted version. Discussion regarding resolution effects has changed; additional analysis into galactic and gravitational effects has been adde

    How Can Conservation Help? Using Land Conservation to Address Other Economic and Social Issues

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    2007 Berkely Workshop Summary and Background Materials Pocantico Conference Center, Tarrytown, New York, June 8-10, 2007 Hosted by the Land Trust Alliance and the Yale School of Forestry & Environmental Studie

    The Vehiculatio in Roman Imperial Regulation: Particular Solutions to a Systematic Problem

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    Category: World History As the Roman Empire pushed its frontiers beyond the Mediterranean world, imperial authorities from Augustus onward faced a serious challenge: information transfer. The government of the early Roman Empire was famously lean in its bureaucracy and relied on small teams of imperial specialists (hated as spies) and military officers selected by governors to carry official documents great distances. These individuals traveled using an ad hoc system designed to take advantage of whatever hospitality existed along the Roman roadways. Messengers commandeered food, buildings, animals, and even guides for most legs of their journey. Official travel passes issued with imperial and gubernatorial authority granted the messengers the power to conduct these impromptu seizures of valuable resources, but this led to a problem: forged travel documents and abuses of the system. Such abuses placed onerous burdens on the citizens living under Roman rule, whose only recourse was to appeal to the emperors and governors for recompense. Literary sources from the Roman Empire lay out basic information about the imperial transport system, known as the vehiculatio, and other primary documents, including regulatory inscriptions and papyri, provide glimpses into how this system functioned (or failed) on the ground. The pleas of Roman provincials seeking restitution for excessive and unlawful vehiculatio requisitions continued throughout the early Roman Empire, as attested by fifteen documents selected for this analysis. A look at these primary documents reveals two serious flaws in the imperial government of the ancient vehiculatio: 1) Roman emperors found fault with morally corrupt individuals and sought to punish these persons rather than investigate problems with the ad hoc transportation itself; 2) Roman emperors issued orders and proscribed punishments without properly considering the provincial governors’ practical ability to deal with problems on the ground. The mistake of the emperors was to adopt particular solutions to what was a systematic problem—a failure of leadership with broader implications about systematic problems in government throughout world history

    Environmental Regulation in Europe: Hazardous Waste and Contaminated Sites

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    The purpose of this Article is to describe the general system of environmental regulation in the European Community ( EC ) and to offer a practical perspective on that system. In order to do so, the Article has several parts. Following this introduction, Section II provides a brief overview of the European Community, its institutions and its basic approach to environmental regulation. Section III offers observations as to some of the major differences in approach to environmental regulation between the EC and the United States. By way of example of how the system works in practice, Sections IV and V provide more detailed reviews of the EC\u27s efforts to address the problems of safely managing hazardous wastes and responding to contaminated sites. Finally, in Section VI, some conclusions are drawn as to the implications of recent developments in EC environmental regulation for companies operating or investing in Europe
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