4,289 research outputs found

    The Design of Cruciform Test Specimens for Planar Biaxial Testing of Fabrics for Inflatable Aerodynamic Decelerators

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    A preliminary analytical study was conducted to investigate the effects of cruciform test specimen geometries on strain distribution uniformity in the central gage section under biaxial loads. Three distinct specimen geometries were considered while varying the applied displacements in the two orthogonal directions. Two sets of woven fabric material properties found in literature were used to quantify the influence of specimen geometries on the resulting strain distributions. The uniformity of the strain distribution is quantified by taking the ratio between the two orthogonal strain components and characterizing its gradient across the central area of the gage section. The analysis results show that increasing the specimen s length relative to its width promotes a more uniform strain distribution in the central section of the cruciform test specimen under equibiaxial enforced tensile displacements. However, for the two sets of material properties used in this study, this trend did not necessary hold, when the enforced tensile displacements in the two orthogonal directions were not equal. Therefore, based on the current study, a tail length that is 1.5 times that of the tail width is recommended to be the baseline/initial specimen design

    The eye of Persepolis’ tiger : how melancholy and nostalgia resonate through Satrapi’s animated film

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    Will Eisner coined the term sequential art to refer to comic strips/books and graphic novels, while arguing that this distinct discipline not only has much in common with film-making but it is in fact a forerunner to film-making. Sequential art is a powerful form of popular culture. However, the scholarly community has generally ignored this popular form of art. This article discusses the animated film Persepolis (Paronnaud and Satrapi, 2007) and explores the ways in which animation is used. We analyse this film in terms of the cultural memory discourse and suggest that this film not only creates a melancholic cultural memory of the past it negotiates, but also, paradoxically, it generates a nostalgic one. As we shall argue, the film’s inherent melancholy and nostalgia allegorically communicate a quest for identity in our present-day societies

    Professional Responsibility and Liability Aspects of Vereins, the Swiss Army Knife of Global Law Firm Combinations

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    (Excerpt) Looking ahead, Part II of this Article provides a general overview of the verein model and its governing charter. Part III highlights a variety of ethical considerations for lawyers in verein member firms that are subject to ethics rules based on the Model Rules of Professional Conduct. These include lawyers\u27 obligation to communicate to clients the relationships between the verein and its member firms, the imputation of conflicts of interest between member firms, and fee-splitting among member firms. Part IV discusses previous efforts to hold vereins and their member firms vicariously liable for the misconduct of another member firm. These cases have involved global accounting firms structured as vereins; vicarious liability among verein member law firms has yet to be tested. Part IV also examines whether the reported push by law firms organized as vereins toward full global integration among their members may perhaps lay the groundwork for collective liability

    Professional Responsibility and Liability Aspects of Vereins, the Swiss Army Knife of Global Law Firm Combinations

    Get PDF
    (Excerpt) Looking ahead, Part II of this Article provides a general overview of the verein model and its governing charter. Part III highlights a variety of ethical considerations for lawyers in verein member firms that are subject to ethics rules based on the Model Rules of Professional Conduct. These include lawyers\u27 obligation to communicate to clients the relationships between the verein and its member firms, the imputation of conflicts of interest between member firms, and fee-splitting among member firms. Part IV discusses previous efforts to hold vereins and their member firms vicariously liable for the misconduct of another member firm. These cases have involved global accounting firms structured as vereins; vicarious liability among verein member law firms has yet to be tested. Part IV also examines whether the reported push by law firms organized as vereins toward full global integration among their members may perhaps lay the groundwork for collective liability

    Avoiding Biased Clinical Machine Learning Model Performance Estimates in the Presence of Label Selection

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    When evaluating the performance of clinical machine learning models, one must consider the deployment population. When the population of patients with observed labels is only a subset of the deployment population (label selection), standard model performance estimates on the observed population may be misleading. In this study we describe three classes of label selection and simulate five causally distinct scenarios to assess how particular selection mechanisms bias a suite of commonly reported binary machine learning model performance metrics. Simulations reveal that when selection is affected by observed features, naive estimates of model discrimination may be misleading. When selection is affected by labels, naive estimates of calibration fail to reflect reality. We borrow traditional weighting estimators from causal inference literature and find that when selection probabilities are properly specified, they recover full population estimates. We then tackle the real-world task of monitoring the performance of deployed machine learning models whose interactions with clinicians feed-back and affect the selection mechanism of the labels. We train three machine learning models to flag low-yield laboratory diagnostics, and simulate their intended consequence of reducing wasteful laboratory utilization. We find that naive estimates of AUROC on the observed population undershoot actual performance by up to 20%. Such a disparity could be large enough to lead to the wrongful termination of a successful clinical decision support tool. We propose an altered deployment procedure, one that combines injected randomization with traditional weighted estimates, and find it recovers true model performance

    DeepCare: A Deep Dynamic Memory Model for Predictive Medicine

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    Personalized predictive medicine necessitates the modeling of patient illness and care processes, which inherently have long-term temporal dependencies. Healthcare observations, recorded in electronic medical records, are episodic and irregular in time. We introduce DeepCare, an end-to-end deep dynamic neural network that reads medical records, stores previous illness history, infers current illness states and predicts future medical outcomes. At the data level, DeepCare represents care episodes as vectors in space, models patient health state trajectories through explicit memory of historical records. Built on Long Short-Term Memory (LSTM), DeepCare introduces time parameterizations to handle irregular timed events by moderating the forgetting and consolidation of memory cells. DeepCare also incorporates medical interventions that change the course of illness and shape future medical risk. Moving up to the health state level, historical and present health states are then aggregated through multiscale temporal pooling, before passing through a neural network that estimates future outcomes. We demonstrate the efficacy of DeepCare for disease progression modeling, intervention recommendation, and future risk prediction. On two important cohorts with heavy social and economic burden -- diabetes and mental health -- the results show improved modeling and risk prediction accuracy.Comment: Accepted at JBI under the new name: "Predicting healthcare trajectories from medical records: A deep learning approach

    Poststroke Trajectories: The Process of Recovery Over the Longer Term Following Stroke

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    We adopted a grounded theory approach to explore the process of recovery experienced by stroke survivors over the longer term who were living in the community in the United Kingdom, and the interacting factors that are understood to have shaped their recovery trajectories. We used a combination of qualitative methods. From the accounts of 22 purposively sampled stroke survivors, four different recovery trajectories were evident: (a) meaningful recovery, (b) cycles of recovery and decline, (c) ongoing disruption, (d) gradual, ongoing decline. Building on the concept of the illness trajectory, our findings demonstrate how multiple, interacting factors shape the process and meaning of recovery over time. Such factors included conception of recovery and meanings given to the changing self, the meanings and consequences of health and illness experiences across the life course, loss, sense of agency, and enacting relationships. Awareness of the process of recovery will help professionals better support stroke survivors

    Detecting the Cosmic Gravitational Wave Background with the Big Bang Observer

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    The detection of the Cosmic Microwave Background Radiation (CMB) was one of the most important cosmological discoveries of the last century. With the development of interferometric gravitational wave detectors, we may be in a position to detect the gravitational equivalent of the CMB in this century. The Cosmic Gravitational Background (CGB) is likely to be isotropic and stochastic, making it difficult to distinguish from instrument noise. The contribution from the CGB can be isolated by cross-correlating the signals from two or more independent detectors. Here we extend previous studies that considered the cross-correlation of two Michelson channels by calculating the optimal signal to noise ratio that can be achieved by combining the full set of interferometry variables that are available with a six link triangular interferometer. In contrast to the two channel case, we find that the relative orientation of a pair of coplanar detectors does not affect the signal to noise ratio. We apply our results to the detector design described in the Big Bang Observer (BBO) mission concept study and find that BBO could detect a background with Ωgw>2.2×10−17\Omega_{gw} > 2.2 \times 10^{-17}.Comment: 15 pages, 12 Figure

    Higher Order Corrections to the Primordial Gravitational Wave Spectrum and its Impact on Parameter Estimates for Inflation

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    We study the impact of the use of the power series expression for the primordial tensor spectrum on parameter estimation from future direct detection gravitational wave experiments. The spectrum approximated by the power series expansion may give large deviation from the true (fiducial) value when it is normalized at CMB scale because of the large separation between CMB and direct detection scales. We derive the coefficients of the higher order terms of the expansion up to the sixth order within the framework of the slow-roll approximation and investigate how well the inclusion of higher order terms improves the analytic prediction of the spectrum amplitude by comparing with numerical results. Using the power series expression, we consider future constraints on inflationary parameters expected from direct detection experiments of the inflationary gravitational wave background and show that the truncation of the higher order terms can lead to incorrect evaluation of the parameters. We present two example models; a quadratic chaotic inflation model and mixed inflaton and curvaton model with a quartic inflaton potential.Comment: 25 pages, 7 figures, revised version accepted by JCA
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