656 research outputs found

    Effects of impact noise on the hearing of military personnel

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    Shooting is an activity that exposes military personnel to noise impact, which may cause irreversible effects on hearing. Objective: To evaluate impact noise on the hearing of military personnel that practice shooting. Study design: A case-control retrospective study. Methods: 115 military personnel were enrolled; 65 had been exposed to impact noise and 50 were non-exposed. Firearm noise levels were evaluated, subjects answered a questionnaire and underwent threshold tonal audiometry and otoacoustic emissions testing. Results: The average noise level was 125dB(C). Most subjects (78%) believe that noise may cause hearing loss; nearly all (92.3%) used ear noise protectors while shooting, but most (32.3%) had never received guidance for using this equipment. There were significant differences between the two groups in relation to changes suggesting impact noise-induced hearing loss. Conclusion: The differences between groups show that noise-exposed military personnel are more likely to develop hearing loss. The goal of a hearing conservation program for this population should be to preserve hearing and educate these individuals about the importance of using hearing protection correctly.77674775

    Diffusion methods for wind power ramp detection

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    The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-38679-4_9Proceedings of 12th International Work-Conference on Artificial Neural Networks, IWANN 2013, Puerto de la Cruz, Tenerife, Spain, June 12-14, 2013, Part IThe prediction and management of wind power ramps is currently receiving large attention as it is a crucial issue for both system operators and wind farm managers. However, this is still an issue far from being solved and in this work we will address it as a classification problem working with delay vectors of the wind power time series and applying local Mahalanobis K-NN search with metrics derived from Anisotropic Diffusion methods. The resulting procedures clearly outperform a random baseline method and yield good sensitivity but more work is needed to improve on specificity and, hence, precision.With partial support from Spain's grant TIN2010-21575- C02-01 and the UAM-ADIC Chair for Machine Learning. The rst author is also supported by an FPI-UAM grant and kindly thanks the Applied Mathematics Department of Yale University for receiving her during her visits. The second author is supported by the FPU-MEC grant AP2008-00167

    Global well-posedness of the 3-D full water wave problem

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    We consider the problem of global in time existence and uniqueness of solutions of the 3-D infinite depth full water wave problem. We show that the nature of the nonlinearity of the water wave equation is essentially of cubic and higher orders. For any initial interface that is sufficiently small in its steepness and velocity, we show that there exists a unique smooth solution of the full water wave problem for all time, and the solution decays at the rate 1/t1/t.Comment: 60 page

    A Rigorous Justification of the Modulation Approximation to the 2D Full Water Wave Problem

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    We consider the 2D inviscid incompressible irrotational infinite depth water wave problem neglecting surface tension. Given wave packet initial data, we show that the modulation of the solution is a profile traveling at group velocity and governed by a focusing cubic nonlinear Schrodinger equation, with rigorous error estimates in Sobolev spaces. As a consequence, we establish existence of solutions of the water wave problem in Sobolev spaces for times in the NLS regime provided the initial data is suitably close to a wave packet of sufficiently small amplitude in Sobolev spaces

    Hormander class of pseudo-differential operators on compact Lie groups and global hypoellipticity

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    In this paper we give several global characterisations of the Hormander class of pseudo-differential operators on compact Lie groups. The result is applied to give criteria for the ellipticity and the global hypoellipticity of pseudo-differential operators in terms of their matrix-valued full symbols. Several examples of the first and second order globally hypoelliptic differential operators are given. Where the global hypoelliptiticy fails, one can construct explicit examples based on the analysis of the global symbols.Comment: 20 page

    Weighted norm inequalities for polynomial expansions associated to some measures with mass points

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    Fourier series in orthogonal polynomials with respect to a measure Îœ\nu on [−1,1][-1,1] are studied when Îœ\nu is a linear combination of a generalized Jacobi weight and finitely many Dirac deltas in [−1,1][-1,1]. We prove some weighted norm inequalities for the partial sum operators SnS_n, their maximal operator S∗S^* and the commutator [Mb,Sn][M_b, S_n], where MbM_b denotes the operator of pointwise multiplication by b \in \BMO. We also prove some norm inequalities for SnS_n when Îœ\nu is a sum of a Laguerre weight on R+\R^+ and a positive mass on 00

    Resolvent Estimates in L^p for the Stokes Operator in Lipschitz Domains

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    We establish the LpL^p resolvent estimates for the Stokes operator in Lipschitz domains in RdR^d, d≄3d\ge 3 for ∣1p−1/2∣<12d+Ï”|\frac{1}{p}-1/2|< \frac{1}{2d} +\epsilon. The result, in particular, implies that the Stokes operator in a three-dimensional Lipschitz domain generates a bounded analytic semigroup in LpL^p for (3/2)-\varep < p< 3+\epsilon. This gives an affirmative answer to a conjecture of M. Taylor.Comment: 28 page. Minor revision was made regarding the definition of the Stokes operator in Lipschitz domain

    Local Interpretation Methods to Machine Learning Using the Domain of the Feature Space

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    As machine learning becomes an important part of many real world applications affecting human lives, new requirements, besides high predictive accuracy, become important. One important requirement is transparency, which has been associated with model interpretability. Many machine learning algorithms induce models difficult to interpret, named black box. Moreover, people have difficulty to trust models that cannot be explained. In particular for machine learning, many groups are investigating new methods able to explain black box models. These methods usually look inside the black models to explain their inner work. By doing so, they allow the interpretation of the decision making process used by black box models. Among the recently proposed model interpretation methods, there is a group, named local estimators, which are designed to explain how the label of particular instance is predicted. For such, they induce interpretable models on the neighborhood of the instance to be explained. Local estimators have been successfully used to explain specific predictions. Although they provide some degree of model interpretability, it is still not clear what is the best way to implement and apply them. Open questions include: how to best define the neighborhood of an instance? How to control the trade-off between the accuracy of the interpretation method and its interpretability? How to make the obtained solution robust to small variations on the instance to be explained? To answer to these questions, we propose and investigate two strategies: (i) using data instance properties to provide improved explanations, and (ii) making sure that the neighborhood of an instance is properly defined by taking the geometry of the domain of the feature space into account. We evaluate these strategies in a regression task and present experimental results that show that they can improve local explanations
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