The Experts below are selected from a list of 207144 Experts worldwide ranked by ideXlab platform
S B Healy - One of the best experts on this subject based on the ideXlab platform.
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a nonlinear optimal estimation Inverse Method for radio occultation measurements of temperature humidity and surface pressure
Journal of Geophysical Research, 2000Co-Authors: Paul I Palmer, J J Barnett, J R Eyre, S B HealyAbstract:An optimal estimation Inverse Method is presented which can be used to retrieve simultaneously vertical profiles of temperature and specific humidity, in addition to surface pressure, from satellite-to-satellite radio occultation observations of the Earth's atmosphere. The Method is a nonlinear, maximum a posteriori technique which can accommodate most aspects of the real radio occultation problem and is found to be stable and to converge rapidly in most cases. The optimal estimation Inverse Method has two distinct advantages over the analytic Inverse Method in that it accounts for some of the effects of horizontal gradients and is able to retrieve optimally temperature and humidity simultaneously from the observations. It is also able to account for observation noise and other sources of error. Combined, these advantages ensure a realistic retrieval of atmospheric quantities. A complete error analysis emerges naturally from the optimal estimation theory, allowing a full characterization of the solution. Using this analysis, a quality control scheme is implemented which allows anomalous retrieval conditions to be recognized and removed, thus preventing gross retrieval errors. The Inverse Method presented in this paper has been implemented for bending angle measurements derived from GPS/MET radio occultation observations of the Earth. Preliminary results from simulated data suggest that these observations have the potential to improve numerical weather prediction model analyses significantly throughout their vertical range.
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a non linear optimal estimation Inverse Method for radio occultation measurements of temperature humidity and surface pressure
arXiv: Atmospheric and Oceanic Physics, 2000Co-Authors: Paul I Palmer, J J Barnett, J R Eyre, S B HealyAbstract:An optimal estimation Inverse Method is presented which can be used to retrieve simultaneously vertical profiles of temperature and specific humidity, in addition to surface pressure, from satellite-to-satellite radio occultation observations of the Earth's atmosphere. The Method is a non-linear, maximum {\it a posteriori} technique which can accommodate most aspects of the real radio occultation problem and is found to be stable and to converge rapidly in most cases. The optimal estimation Inverse Method has two distinct advantages over the analytic Inverse Method in that it accounts for some of the effects of horizontal gradients and is able to retrieve optimally temperature and humidity simultaneously from the observations. It is also able to account for observation noise and other sources of error. Combined, these advantages ensure a realistic retrieval of atmospheric quantities. A complete error analysis emerges naturally from the optimal estimation theory, allowing a full characterisation of the solution. Using this analysis a quality control scheme is implemented which allows anomalous retrieval conditions to be recognised and removed, thus preventing gross retrieval errors. The Inverse Method presented in this paper has been implemented for bending angle measurements derived from GPS/MET radio occultation observations of the Earth. Preliminary results from simulated data suggest that these observations have the potential to improve NWP model analyses significantly throughout their vertical range.
Atsushi Yamaji - One of the best experts on this subject based on the ideXlab platform.
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determination of stresses from heterogeneous focal mechanism data an adaptation of the multiple Inverse Method
Tectonophysics, 2008Co-Authors: Makoto Otsubo, Atsushi Yamaji, Atsuki KuboAbstract:Abstract A new Method is proposed to separate stresses from earthquake focal mechanism data (double couple component of focal mechanisms) from spatially or temporarily varying state of stress. The underlying multiple Inverse Method was originally devised for geological fault-slip data, but we have adapted its resampling scheme to focal mechanism data to cope with the nodal planes ambiguity problem. The stresses compatible with a dataset are recognized as the clusters of reduced stress tensors. The clusters are identified with the k -means clustering. The uncertainty of the stresses are evaluated from the spread of the clusters. The technique is shown to successfully determine valid stresses from simulated data. We have also applied the technique to natural data from southwestern Japan.
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computerized identification of stress tensors determined from heterogeneous fault slip data by combining the multiple Inverse Method and k means clustering
Journal of Structural Geology, 2006Co-Authors: Makoto Otsubo, Katsushi Sato, Atsushi YamajiAbstract:The multiple Inverse Method is a resampling technique that can separate stresses from heterogeneous fault-slip data. Numerous optimal stresses are determined for each extracted subset of data, and the clusters of these stresses are thought to represent significant solutions. Hitherto, the clusters have had to be visually recognized on stereonets. This study computerized the identification of the clusters by using the k-means clustering technique. We tested the technique using artificial datasets with known solutions. As a result, it was found that the present Method detected objectively the correct solutions. In addition, the spread of each cluster was evaluated to indicate the confidence levels of the identified stresses that were represented by the cluster centers.
Makoto Otsubo - One of the best experts on this subject based on the ideXlab platform.
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determination of stresses from heterogeneous focal mechanism data an adaptation of the multiple Inverse Method
Tectonophysics, 2008Co-Authors: Makoto Otsubo, Atsushi Yamaji, Atsuki KuboAbstract:Abstract A new Method is proposed to separate stresses from earthquake focal mechanism data (double couple component of focal mechanisms) from spatially or temporarily varying state of stress. The underlying multiple Inverse Method was originally devised for geological fault-slip data, but we have adapted its resampling scheme to focal mechanism data to cope with the nodal planes ambiguity problem. The stresses compatible with a dataset are recognized as the clusters of reduced stress tensors. The clusters are identified with the k -means clustering. The uncertainty of the stresses are evaluated from the spread of the clusters. The technique is shown to successfully determine valid stresses from simulated data. We have also applied the technique to natural data from southwestern Japan.
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computerized identification of stress tensors determined from heterogeneous fault slip data by combining the multiple Inverse Method and k means clustering
Journal of Structural Geology, 2006Co-Authors: Makoto Otsubo, Katsushi Sato, Atsushi YamajiAbstract:The multiple Inverse Method is a resampling technique that can separate stresses from heterogeneous fault-slip data. Numerous optimal stresses are determined for each extracted subset of data, and the clusters of these stresses are thought to represent significant solutions. Hitherto, the clusters have had to be visually recognized on stereonets. This study computerized the identification of the clusters by using the k-means clustering technique. We tested the technique using artificial datasets with known solutions. As a result, it was found that the present Method detected objectively the correct solutions. In addition, the spread of each cluster was evaluated to indicate the confidence levels of the identified stresses that were represented by the cluster centers.
Asri Jaya - One of the best experts on this subject based on the ideXlab platform.
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paleostress reconstruction from calcite twin and fault slip data using the multiple Inverse Method in the east walanae fault zone implications for the neogene contraction in south sulawesi indonesia
Journal of Structural Geology, 2013Co-Authors: Asri Jaya, Osamu NishikawaAbstract:Abstract A new approach for paleostress analysis using the multiple Inverse Method with calcite twin data including untwinned e-plane was performed in the East Walanae fault (EWF) zone in South Sulawesi, Indonesia. Application of untwinned e-plane data of calcite grain to constrain paleostress determination is the first attempt for this Method. Stress states caused by the collision of the south-east margin of Sundaland with the Australian microcontinents during the Pliocene were successfully detected from a combination of calcite-twin data and fault–slip data. This Pliocene NE–SW-to-E–W-directed maximum compression activated the EWF as a reverse fault with a dextral component of slip with pervasive development of secondary structures in the narrow zone between Bone Mountain and Walanae Depression.
Wilton Pereira Da Silva - One of the best experts on this subject based on the ideXlab platform.
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calculation of the convective heat transfer coefficient and thermal diffusivity of cucumbers using numerical simulation and the Inverse Method
Journal of Food Science and Technology-mysore, 2014Co-Authors: Wilton Pereira Da Silva, Cleide M D P S E SilvaAbstract:Cooling of fruits and vegetables, immediately after the harvest, has been a widely used Method for maximizing post-harvest life. In this paper, an optimization algorithm and a numerical solution are used to determine simultaneously the convective heat transfer coefficient, hH, and the thermal diffusivity, α, for an individual solid with cylindrical shape, using experimental data obtained during its cooling. To this end, the one-dimensional diffusion equation in cylindrical coordinates is discretized and numerically solved through the finite volume Method, with a fully implicit formulation. This solution is coupled to an optimizer based on the Inverse Method, in which the chi-square referring to the fit of the numerical simulation to the experimental data is used as objective function. The optimizer coupled to the numerical solution was applied to experimental data relative to the cooling of a cucumber. The obtained results for α and hH were coherent with the values available in the literature. With the results obtained in the optimization process, the cooling kinetics of cucumbers was described in details.
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determination of effective diffusivity and convective mass transfer coefficient for cylindrical solids via analytical solution and Inverse Method application to the drying of rough rice
Journal of Food Engineering, 2010Co-Authors: Wilton Pereira Da Silva, Jurgen W Precker, Cleide M D P S E Silva, Josivanda Palmeira GomesAbstract:A Method is proposed for the simultaneous determination of the effective diffusivity and convective mass transfer coefficient in solids which can be considered as infinite cylinders. The Inverse Method was used to fit the analytical solution of the diffusion equation with convective boundary condition to experimental data of thin-layer drying kinetics of products with cylindrical shape. The proposed Method was applied to the drying kinetic of rough rice, using experimental data available in the literature. The statistical indicators show that describing the diffusion process with convective boundary condition is more accurate than the description with boundary condition of the first kind, commonly found in the literature.
