12,663 research outputs found

    Application of Market Models to Network Equilibrium Problems

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    We present a general two-side market model with divisible commodities and price functions of participants. A general existence result on unbounded sets is obtained from its variational inequality re-formulation. We describe an extension of the network flow equilibrium problem with elastic demands and a new equilibrium type model for resource allocation problems in wireless communication networks, which appear to be particular cases of the general market model. This enables us to obtain new existence results for these models as some adjustments of that for the market model. Under certain additional conditions the general market model can be reduced to a decomposable optimization problem where the goal function is the sum of two functions and one of them is convex separable, whereas the feasible set is the corresponding Cartesian product. We discuss some versions of the partial linearization method, which can be applied to these network equilibrium problems.Comment: 18 pages, 3 table

    How Priming Innocence Influences Public Opinion on Police Misconduct and False Convictions: A Research Note

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    Issues of innocence have become more salient to the public in recent years, including the problem of police misconduct. However, citizens also tend to be supportive of the police, perceiving them as ethical, honest, and trustworthy. Using a survey experiment with a nationally representative sample, we explore the degree to which public opinion toward police misconduct is influenced by priming respondents on the issue of innocence. We find that reminding citizens of these issues increases their willingness to admit police misconduct that contributes to this problem by roughly 7 percentage points overall. Moreover, this effect is driven by conservatives and, to a lesser extent, moderates, presumably because liberals do not need priming. In contrast, the efficacy of the prime was not affected (i.e., moderated) by the race of the respondent. We place these results in the context of the current debate regarding police use of force as well as the ideological divide in rhetoric surrounding the recent string of high-profile police shootings

    Understanding perceptions of citizen demeanour: using an experimental design to understand the impact of encounter and observer characteristics

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    Systematic social observations of police-citizen encounters have revealed that citizen demeanour is an important predictor of outcomes (e.g. arrests and searches). Drawing from research on stereotypes and impression formation, we examine whether characteristics of the encounter and/or observer affect how respondents perceive demeanour. We exposed undergraduates (n = 255) to a randomly rotated series of five between-subjects design, in which characteristics of the encounter (citizen race, gender, or age; officer gender; neighbourhood context) and the level of demeanour displayed were manipulated. OLS regression was used to examine how these manipulations interact to produce our dependent variable – perceptions of demeanour – and whether characteristics of the observer matter for perceptions, independent of the manipulations. We find that some aspects of the encounter, specifically officer gender and the socio-economic context of the neighbourhood, influence perceptions of demeanour. Previous victimisation, observers’ race, and perceptions of the police also impact how demeanour is perceived. These findings suggest that understanding the impact of citizen demeanour on police-citizen encounters requires consideration of encounter and observer characteristics

    Reliability-Based Design of Thermal Protection Systems with Support Vector Machines

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    The primary objective of this work was to develop a computationally efficient and accurate approach to reliability analysis of thermal protection systems using support vector machines. An adaptive sampling approach was introduced informs a iterative support vector machine approximation of the limit state function used for measuring reliability. The proposed sampling approach efficient adds samples along the limit state function until the reliability approximation is converged. This methodology is applied to two samples, mathematical functions to test and demonstrate the applicability. Then, the adaptive sampling-based support vector machine approach is applied to the reliability analysis of a thermal protection system. The results of all three problems highlight the potential capability of the new approach in terms of accuracy and computational saving in determining thermal protection system reliability

    Calibration Probe Uncertainty and Validation for the Hypersonic Material Environmental Test System

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    This paper presents an uncertainty analysis of the stagnation-point calibration probe surface predictions for conditions that span the performance envelope of the Hypersonic Materials Environmental Test System facility located at NASA Langley Research Center. A second-order stochastic expansion was constructed over 47 uncertain parameters to evaluate the sensitivities, identify the most significant uncertain variables, and quantify the uncertainty in the stagnation-point heat flux and pressure predictions of the calibration probe for a low- and high-enthalpy test condition. A sensitivity analysis showed that measurement bias uncertainty is the most significant contributor to the stagnation-point pressure and heat flux variance for the low-enthalpy condition. For the high-enthalpy condition, a paradigm shift in sensitivities revealed the computational fluid dynamics model input uncertainty as the main contributor. A comparison between the prediction and measurement of the stagnation-point conditions under uncertainty showed that there was evidence of statistical disagreement. A validation metric was proposed and applied to the prediction uncertainty to account for the statistical disagreement when compared to the possible stagnation-point heat flux and pressure measurements

    Robert Milton Zollinger, M.D., teacher, surgeon, soldier, and farmer.

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    From Humble roots, Dr. Robert Milton Zollinger worked his way to a position in history among the giants of American surgery. He was born on September 4, 1903, in the central Ohio town of Millersport, the son of Elmira and William Zollinger. Neither of his parents had a high school education, but they supported education and always expressed a confidence that young Robert would be successful at anything he attempted.1 He had aspirations of attending West Point, a dream that was never fulfilled when he decided to be a surgeon. On being informed of his son’s intentions, Zollinger’s father bestowed on him advice that he ostensibly adhered to throughout his career: ‘‘If you are going to be a doctor, be a good one.’
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