The Experts below are selected from a list of 129231 Experts worldwide ranked by ideXlab platform
Henri Cohen - One of the best experts on this subject based on the ideXlab platform.
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Haberland’s formula and Numerical Computation of Petersson scalar products
The Open Book Series, 2013Co-Authors: Henri CohenAbstract:We study several methods for the Numerical Computation of Petersson scalar products, and in particular we prove a generalization of Haberland's formula to any subgroup of finite index G of Gamma = PSL_2 (Z), which gives a fast method to compute these scalar products when a Hecke eigenbasis is not necessarily available.
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Haberland's formula and Numerical Computation of Petersson scalar products
2012Co-Authors: Henri CohenAbstract:We study several methods for the Numerical Computation of Petersson scalar products, and in particular we prove a generalization of Haberland's formula to any subgroup of finite index G of Gamma = PSL_2 (Z), which gives a fast method to compute these scalar products when a Hecke eigenbasis is not necessarily available.
Alan Genz - One of the best experts on this subject based on the ideXlab platform.
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Numerical Computation of rectangular bivariate and trivariate normal and t probabilities
Statistics and Computing, 2004Co-Authors: Alan GenzAbstract:Algorithms for the Computation of bivariate and trivariate normal and t probabilities for rectangles are reviewed. The algorithms use Numerical integration to approximate transformed probability distribution integrals. A generalization of Plackett's formula is derived for bivariate and trivariate t probabilities. New methods are described for the Numerical Computation of bivariate and trivariate t probabilities. Test results are provided, along with recommendations for the most efficient algorithms for single and double precision Computations.
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Numerical Computation of Multivariate Normal Probabilities
Journal of Computational and Graphical Statistics, 1992Co-Authors: Alan GenzAbstract:Abstract The Numerical Computation of a multivariate normal probability is often a difficult problem. This article describes a transformation that simplifies the problem and places it into a form that allows efficient calculation using standard Numerical multiple integration algorithms. Test results are presented that compare implementations of two algorithms that use the transformation with currently available software.
Yann Kerr - One of the best experts on this subject based on the ideXlab platform.
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Numerical Computation of the L-band emission and scattering of soil layers with consideration of moisture and temperature gradients
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012Co-Authors: François Demontoux, Heather Lawrence, L.g. Kosolapova, Philippe Paillou, Jean-pierre Wigneron, V. L. Mironov, Yann KerrAbstract:In the context of the Soil Moisture and Ocean Salinity mission, we present a study of the emission of rough surfaces at 1.4 GHz and the effects of moisture and temperature gradients. A new approach for the calculation of rough surface scattering and emission at L-band has been validated for the case of scattering from rough surfaces of Gaussian autocorrelation function. This approach relies on the use of ANSYS's Numerical Computation software HFSS, which in turn solves Maxwell's equations using the Finite Element Method. The interest of this approach is that it can be extended to calculate the emission and scattering of complicated multilayer media. In this paper we present the work we done to use FEM method to compute thermal effects and water infiltration effects in ground. We firstly present the effects of water infiltration in ground then we present results of Computations on soils partially or completely frozen.
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Numerical Computation of the l-band emission and scattering of soil layers with consideration of moisture and temperature gradients
2012Co-Authors: François Demontoux, Heather Lawrence, V. Mironov, L.g. Kosolapova, Philippe Paillou, Jean-pierre Wigneron, Yann KerrAbstract:In the context of the European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) mission, we present a study of the emission of rough surfaces at 1.4 GHz and the effects of moisture and temperature gradients. Surface roughness has been studied in some depth in the literature as it is a key influencing parameter on ground emission. A new approach for the calculation of rough surface scattering and emission at L-band has recently been validated for the case of scattering from a single layer rough surface of Gaussian autocorrelation function [3]. This approach relies on the use of ANSYS's Numerical Computation software HFSS (High Frequency Structure Simulator), which in turn solves Maxwell's equations using the Finite Element Method (FEM). The interest of this approach is that it can be extended to calculate the emission and scattering of complicated multilayer media, including features such as volume effects, gradients effects and inclusions, as well as rough surfaces. This is therefore especially useful for the problem of the emission from soil-litter systems in forests. At L band, volume effects in the upper layer of soil should be taken into account. In particular, moisture or thermal phenomena lead to the presence of gradients. In this paper we present the work we have done to use FEM (Finite Element Method) method to compute thermal effects and water infiltration effects in ground. Coupling electromagnetic and thermal Computation we are able to study scattering of media such as permafrost or effects of rapid changes in temperature condition. It can also be very useful for global observations with a frequent repeat coverage (future NASA Soil Moisture Active/Passive mission SMAP). In the present study we firstly present the effects of water infiltration in ground (as moisture gradients) on the emissivity and bi-static scattering coefficient of soil. Then we will present results of Computations on soils partially or completely frozen.
Young Soo Suh - One of the best experts on this subject based on the ideXlab platform.
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Stability of time delay systems using Numerical Computation of argument principles
Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 1Co-Authors: Young Soo SuhAbstract:The paper proposes a new Numerical method to check the stability of a general class of time delay systems. The proposed method checks whether there are characteristic roots whose real values are nonnegative through two steps. First, rectangular bounds of characteristic roots, whose real values are nonnegative, are computed. Next, existence of roots inside the bounds are checked using Numerical Computation of argument principles. An adaptive discretization is proposed for the Numerical Computation of argument principles.
François Demontoux - One of the best experts on this subject based on the ideXlab platform.
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Numerical Computation of the L-band emission and scattering of soil layers with consideration of moisture and temperature gradients
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012Co-Authors: François Demontoux, Heather Lawrence, L.g. Kosolapova, Philippe Paillou, Jean-pierre Wigneron, V. L. Mironov, Yann KerrAbstract:In the context of the Soil Moisture and Ocean Salinity mission, we present a study of the emission of rough surfaces at 1.4 GHz and the effects of moisture and temperature gradients. A new approach for the calculation of rough surface scattering and emission at L-band has been validated for the case of scattering from rough surfaces of Gaussian autocorrelation function. This approach relies on the use of ANSYS's Numerical Computation software HFSS, which in turn solves Maxwell's equations using the Finite Element Method. The interest of this approach is that it can be extended to calculate the emission and scattering of complicated multilayer media. In this paper we present the work we done to use FEM method to compute thermal effects and water infiltration effects in ground. We firstly present the effects of water infiltration in ground then we present results of Computations on soils partially or completely frozen.
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Numerical Computation of the l-band emission and scattering of soil layers with consideration of moisture and temperature gradients
2012Co-Authors: François Demontoux, Heather Lawrence, V. Mironov, L.g. Kosolapova, Philippe Paillou, Jean-pierre Wigneron, Yann KerrAbstract:In the context of the European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) mission, we present a study of the emission of rough surfaces at 1.4 GHz and the effects of moisture and temperature gradients. Surface roughness has been studied in some depth in the literature as it is a key influencing parameter on ground emission. A new approach for the calculation of rough surface scattering and emission at L-band has recently been validated for the case of scattering from a single layer rough surface of Gaussian autocorrelation function [3]. This approach relies on the use of ANSYS's Numerical Computation software HFSS (High Frequency Structure Simulator), which in turn solves Maxwell's equations using the Finite Element Method (FEM). The interest of this approach is that it can be extended to calculate the emission and scattering of complicated multilayer media, including features such as volume effects, gradients effects and inclusions, as well as rough surfaces. This is therefore especially useful for the problem of the emission from soil-litter systems in forests. At L band, volume effects in the upper layer of soil should be taken into account. In particular, moisture or thermal phenomena lead to the presence of gradients. In this paper we present the work we have done to use FEM (Finite Element Method) method to compute thermal effects and water infiltration effects in ground. Coupling electromagnetic and thermal Computation we are able to study scattering of media such as permafrost or effects of rapid changes in temperature condition. It can also be very useful for global observations with a frequent repeat coverage (future NASA Soil Moisture Active/Passive mission SMAP). In the present study we firstly present the effects of water infiltration in ground (as moisture gradients) on the emissivity and bi-static scattering coefficient of soil. Then we will present results of Computations on soils partially or completely frozen.
