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14
Inversion, error analysis, and validation of GPS/MET occultation data
"... Abstract. The global positioning system meteorology (GPS/MET) experiment was the ®rst practical demonstration of global navigation satellite system (GNSS)based active limb sounding employing the radio occultation technique. This method measures, as principal observable and with millimetric accuracy ..."
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Abstract. The global positioning system meteorology (GPS/MET) experiment was the ®rst practical demonstration of global navigation satellite system (GNSS)based active limb sounding employing the radio occultation technique. This method measures, as principal observable and with millimetric accuracy, the excess phase path (relative to propagation in vacuum) of GNSStransmitted radio waves caused by refraction during passage through the Earth's neutral atmosphere and ionosphere in limb geometry. It shows great potential utility for weather and climate system studies in providing an unique combination of global coverage, high vertical resolution and accuracy, longterm stability, and allweather capability. We ®rst describe our GPS/MET data processing scheme from excess phases
Compilation of a Specialized Functional Language for Massively Parallel Computers
 Journal of Functional Programming
, 2000
"... We propose a parallel specialized language that ensures portable and costpredictable implementations on parallel computers. The language is basically a firstorder, recursionless, strict functional language equipped with a collection of higherorder functions or skeletons. These skeletons apply on ..."
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Cited by 3 (0 self)
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We propose a parallel specialized language that ensures portable and costpredictable implementations on parallel computers. The language is basically a firstorder, recursionless, strict functional language equipped with a collection of higherorder functions or skeletons. These skeletons apply on (nested) vectors and can be grouped in four classes: computation, reorganization, communication, and mask skeletons. The compilation process is described as a series of transformations and analyses leading to spmdlike functional programs which can be directly translated into real parallel code. The language restrictions enforce a programming discipline whose benefit is to allow a static, symbolic, and accurate cost analysis. The parallel cost takes into account both load balancing and communications, and can be statically evaluated even when the actual size of vectors or the number of processors are unknown. It is used to automatically select the best data distribution among a set of standard distributions. Interestingly, this work can be seen as a cross fertilization between techniques developed within the Fortran parallelization, skeleton, and functional programming communities.
Using Spectral Method as an Approximation for Solving Hyperbolic PDEs
, 2008
"... We demonstrate an application of the spectral method as a numerical approximation for solving Hyperbolic PDEs. In this method a finite basis is used for approximating the solutions. In particular, we demonstrate a set of such solutions for cases which would be otherwise almost impossible to solve by ..."
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We demonstrate an application of the spectral method as a numerical approximation for solving Hyperbolic PDEs. In this method a finite basis is used for approximating the solutions. In particular, we demonstrate a set of such solutions for cases which would be otherwise almost impossible to solve by the more routine methods such as the Finite Difference Method. Eigenvalue problems are included in the class of PDEs that are solvable by this method. Although any complete orthonormal basis can be used, we discuss two particularly interesting bases: the Fourier basis and the quantum oscillator eigenfunction basis. We compare and discuss the relative advantages of each of these two bases.
Key words: Longmemory; Resampling; Skewness and kurtosis; ARCH; Monte Carlo; Size correction.
, 1998
"... Asymptotic tests for fractional integration are usually badly sized in small samples, even for normally distributed processes. Furthermore, tests that are wellsized under normality may be severely distorted by nonnormalities and ARCH errors. This paper demonstrates how the bootstrap can be implemen ..."
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Asymptotic tests for fractional integration are usually badly sized in small samples, even for normally distributed processes. Furthermore, tests that are wellsized under normality may be severely distorted by nonnormalities and ARCH errors. This paper demonstrates how the bootstrap can be implemented to correct for such size distortions. It is shown that a welldesigned bootstrap test based on the MRR and GPH tests is exact,
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"... The in#uence of stratospheric intrusions on alpine ozone concentrations ..."
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Sequential Estimation of the Sum of Sinusoidal Model Parameters
"... Estimating the parameters of the sum of a sinusoidal model in presence of additive noise is a classical problem. It is well known to be a di±cult problem when the two adjacent frequencies are not well separated or when the number of components is very large. In this paper we propose a simple sequent ..."
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Estimating the parameters of the sum of a sinusoidal model in presence of additive noise is a classical problem. It is well known to be a di±cult problem when the two adjacent frequencies are not well separated or when the number of components is very large. In this paper we propose a simple sequential procedure to estimate the unknown frequencies and amplitudes of the sinusoidal signals. It is observed that if there are p components in the signal then at the kth (k · p) stage our procedure produces strongly consistent estimators of the k dominant sinusoids. For k> p, the amplitude estimators converge to zero almost surely. Asymptotic distribution of the proposed estimators is also established and it is observed that it coincides with the asymptotic distribution of the least squares estimators. Numerical simulations are performed to observe the performance of the proposed estimators for di®erent sample sizes and for di®erent models. One ECG data and one synthesized data are analyzed for illustrative purpose.
Solving Equations Involving the Catenary with MLAB
"... A 10 foot rope hangs in the form of a catenary with one end attached to a pier at a point 3 feet above the water's surface, and the other end attached at the same height to a boat. If the lowest point on the catenary just touches the water, how far is the boat from the pier? If that distance is ..."
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A 10 foot rope hangs in the form of a catenary with one end attached to a pier at a point 3 feet above the water's surface, and the other end attached at the same height to a boat. If the lowest point on the catenary just touches the water, how far is the boat from the pier? If that distance is ¯xed, does the minimum of the catenary submerge or clear the surface of the water as the tide ebbs? as the tide °ows? 1 Figure 1: A rope ¯xed to a pier and a boat. The lowest point touches the water's surface. It has been known since Leibnitz and Huygens ' time, circa 1691, that a rope or chain tethered at each end hangs in the shape of a catenary curve. Reference 1 gives the mathematical form of a catenary as y(x) = ¯ + ° cosh( x ®, ¯, and ° must be chosen so that the catenary passes through two designated endpoints and the total length of the catenary has the proper value. The length of the catenary with abscissae ranging from x0 to x1 is given by L(x0; x1) = ° [sinh( x1 + ®) ¡ sinh( x0 Choosing a coordinate system that has an xaxis colinear with the line segment that is parallel to the water surface and connects the endpoints of the rope, and a yaxis that is perpendicular to the xaxis and passes through the minimum of the catenary gives rise to 4 equations: 0 = ¯ + ° cosh(®) 3 = ¯ + ° cosh(
Pe heat transfer Peclet number, Pe"2R
, 1999
"... Abstract*Convective di!usion in Poiseuille #ow is investigated for a nonuniform distribution of the di!using constituent at the tube inlet. The analytical solution is provided together with an e$cient method to evaluate it numerically, including an appropriate recurrencecalculation scheme that fac ..."
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Abstract*Convective di!usion in Poiseuille #ow is investigated for a nonuniform distribution of the di!using constituent at the tube inlet. The analytical solution is provided together with an e$cient method to evaluate it numerically, including an appropriate recurrencecalculation scheme that facilitates the numerical e!ort. The solution is illustrated by considering relevant examples from the literature. In particular, homogeneous nucleation in a laminar #ow di!usion chamber is analyzed, and the results show that the usual experimental inlet nonuniformities have a signi"cant in#uence on the calculation of the saturation ratio and the nucleation rate. ( 2000 Elsevier Science
Contents
, 2004
"... Application of timedependent currentdensityfunctional theory to excitations in atoms ..."
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Application of timedependent currentdensityfunctional theory to excitations in atoms
Modeling and Estimation of Symmetric Color Textures
"... In this paper we have considered the sum of threedimensional (3D), sinusoidal model. It is observed that this model can be used quite e®ectively to model symmetric color textures. The estimation problem is particularly di±cult when the adjacent frequencysets are not well separated or when the nu ..."
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In this paper we have considered the sum of threedimensional (3D), sinusoidal model. It is observed that this model can be used quite e®ectively to model symmetric color textures. The estimation problem is particularly di±cult when the adjacent frequencysets are not well separated or when the number of components is very large. Using the fact that the regressor vectors are orthogonal, we propose a simple sequential procedure to estimate the unknown frequencies and amplitudes of the 3D sinusoidal signals. It is observed that if there are p components in the signal then our procedure at the kth (k · p) stage produces strongly consistent estimators of the k dominant sinusoids. For k> p, the amplitude estimators converge to zero almost surely. Asymptotic distribution of the proposed sequential estimators is established and it is observed that it coincides with the asymptotic distribution of the least squares estimators. Numerical simulations are performed to observe the performance of the proposed estimators for di®erent sample sizes and models. One color texture data and one synthesized data are analyzed for illustration.