3,734 research outputs found

    Confidence bands for multivariate and time dependent inverse regression models

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    Uniform asymptotic confidence bands for a multivariate regression function in an inverse regression model with a convolution-type operator are constructed. The results are derived using strong approximation methods and a limit theorem for the supremum of a stationary Gaussian field over an increasing system of sets. As a particular application, asymptotic confidence bands for a time dependent regression function ft(x)f_t(x) (xRd,tRx\in \mathbb {R}^d,t\in \mathbb {R}) in a convolution-type inverse regression model are obtained. Finally, we demonstrate the practical feasibility of our proposed methods in a simulation study and an application to the estimation of the luminosity profile of the elliptical galaxy NGC5017. To the best knowledge of the authors, the results presented in this paper are the first which provide uniform confidence bands for multivariate nonparametric function estimation in inverse problems.Comment: Published at http://dx.doi.org/10.3150/13-BEJ563 in the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

    Generalization of the Manley-Rowe relations for non-periodic signals constrained in bandwidth with finite energy

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    General relations for the energy spectral densities of nonperiodic signals constrained in bandwidth in nonlinear reactances are derived. It is assumed that the charge-voltage characteristics of the reactances are polynomials. In addition certain conditions for the frequency bands of the signals must be met. By contrast with the Manley-Rowe relations integrals with respect to frequency appear instead of the ratios power over frequency. The integrands are energy spectral densities divided by frequency. For parametric devices inequalities can be derived for the ratios of the energy levels in the different circuits and the limiting frequencies of the energy spectral densities. With these inequalities it is possible to determine limits for the energy levels

    On confidence bands for multivariate nonparametric regression

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    In a multivariate nonparametric regression problem with fixed, deterministic design asymptotic, uniform confidence bands for the regression function are constructed. The construction of the bands is based on the asymptotic distribution of the maximal deviation between a suitable nonparametric estimator and the true regression function which is derived by multivariate strong approximation methods and a limit theorem for the supremum of a stationary Gaussian field over an increasing system of sets. The results are derived for a general class of estimators which includes local polynomial estimators as a special case. The finite sample properties of the proposed asymptotic bands are investigated by means of a small simulation study

    Asia-Pacific Trade and Investment Review

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    This book reviews latest trends in trade and investment policy issues facing Asia-Pacific region.Trade, Foreign Direct Investment, Financial Crisis, Environment, Agricultural Trade Liberalization, WTO

    Multiscale inference for a multivariate density with applications to X-ray astronomy

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    In this paper we propose methods for inference of the geometric features of a multivariate density. Our approach uses multiscale tests for the monotonicity of the density at arbitrary points in arbitrary directions. In particular, a significance test for a mode at a specific point is constructed. Moreover, we develop multiscale methods for identifying regions of monotonicity and a general procedure for detecting the modes of a multivariate density. It is is shown that the latter method localizes the modes with an effectively optimal rate. The theoretical results are illustrated by means of a simulation study and a data example. The new method is applied to and motivated by the determination and verification of the position of high-energy sources from X-ray observations by the Swift satellite which is important for a multiwavelength analysis of objects such as Active Galactic Nuclei.Comment: Keywords and Phrases: multiple tests, modes, multivariate density, X-ray astronomy AMS Subject Classification: 62G07, 62G10, 62G2

    Dynamic Political Rhetoric: Electoral, Economic, and Partisan Determinants of Speech-Making in the UK Parliament

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    Parliamentary debate is one major outlet for Members of Parliament (MPs), who spend lots of time preparing for and participating in such discussions. In this paper, we investigate in how far the focus MPs choose in their speeches varies as the economic, partisan and electoral context changes. We choose to study the dynamics nature of speech content in the UK House of Commons, as British MPs enjoy broad discretion regarding the content of their speeches. This paper analyses the constituency, national or partisan focus of all speeches held in the House of Commons between January 1996 and September 2004. We find that government and opposition MPs react differently to contextual changes. Government MPs generally have a higher district focus, which is increased further when the local economy declines and when the governing party becomes more popular
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