The Experts below are selected from a list of 15639 Experts worldwide ranked by ideXlab platform
C. Guerin - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Surface Roughness Heterogeneity and Scattering Behavior for Radar Measurements
IEEE Transactions on Geoscience and Remote Sensing, 2006Co-Authors: M. Zribi, N. Baghdadi, C. GuerinAbstract:The use of a theoretical backscatter model to analyze medium to low spatial resolution microwave data is still very complicated, particularly because of the difficulty in defining a unique Roughness Parameter, capable of adequately representing heterogeneous terrain. In this paper, an approach is proposed for Roughness analysis and the modeling of backscattering, under conditions of surface heterogeneity. This paper is based on the use of a semiempirical backscattering model, defined with a single Roughness Parameter Zs=s2/l (s being the root mean square surface height and l the correlation length). The proposed backscattering model has been validated with integral equation model simulations, for high radar incidence angles, and within its domain of Roughness validity. A range of experimental measurements was used to validate the model expressions. The effective low spatial resolution Roughness, inferred from signals backscattered from a surface of heterogeneous Roughness, is defined for different Roughness classes
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A New Semi-empirical Model for the Analysis of Surface Roughness Heterogeneity
2006 IEEE International Symposium on Geoscience and Remote Sensing, 2006Co-Authors: M. Zribi, N. Baghdadi, C. GuerinAbstract:The use of a theoretical backscatter model to analyse medium to low spatial resolution microwave data is still very complicated, particularly because of the difficulty in defining a unique Roughness Parameter, capable of adequately representing heterogeneous terrain. In this paper, an approach is proposed for Roughness analysis and the modelling of backscattering, under conditions of surface heterogeneity. The proposed backscattering model has been validated with IEM (integral equation model) simulations and radar data , for high radar incidence angles, and within its domain of Roughness validity.
Maxence Bigerelle - One of the best experts on this subject based on the ideXlab platform.
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relation between surface hardening and Roughness induced by ultrasonic shot peening
Tribology International, 2015Co-Authors: J Marteau, Maxence BigerelleAbstract:Abstract This paper is focused on the identification of a relation between surface hardening and Roughness induced by ultrasonic shot peening. A method that dissociates the influence of Roughness from the value of the true macroscopic hardness is applied to AISI 316L stainless steel specimens treated using different processing conditions. The true macroscopic hardness is identified and used to determine the surface Roughness Parameter and scale that give the best relation between hardness and Roughness. A relation is identified between the five point pit height S 5 V Roughness Parameter (local depth of Roughness) and hardness using a high-pass filter with a cut-off of 100 µm. This power function was identified at a scale that corresponds to the size of the shot impacts.
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wavelet theory and belt finishing process influence of wavelet shape on the surface Roughness Parameter values
13th International Conference on Metrology and Properties of Engineering Surfaces, 2011Co-Authors: Zahra Khawaja, G Guillemot, Pierreemmanuel Mazeran, El M Mansori, Maxence BigerelleAbstract:This article presents a multi-scale theory based on wavelet decomposition to characterize the evolution of Roughness in relation with a finishing process or an observed surface property. To verify this approach in production conditions, analyses were developed for the finishing process of the hardened steel by abrasive belts. These conditions are described by seven Parameters considered in the Tagushi experimental design. The main objective of this work is to identify the most relevant Roughness Parameter and characteristic length allowing to assess the influence of finishing process, and to test the relevance of the measurement scale. Results show that wavelet approach allows finding this scale.
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Relevance of Roughness Parameters for describing and modelling machined surfaces
Journal of Materials Science, 2003Co-Authors: Maxence Bigerelle, D Najjar, Alain IostAbstract:Describing and modelling a machined surface require the selection of relevant Roughness Parameters. However, this selection is difficult since a machined surface morphology can be described by a large number of Roughness Parameters. This investigation focuses on the Roughness of metallic surfaces taking for two applications: a) the description of machined surface morphologies produced by grinding b) the relationships between machined surface morphologies (grinding or cold-rolling) and their brightness level when irradiated by the white light beam of an optical glossmeter used for industrial surface quality control. For each application, the aim is to determine, from an objective quantitative point of view, the relevance of one hundred or so surface Roughness Parameters. To reach this objective, a specific software program has been developed to determine a ranking of relevance thanks to the calculation of a computed statistical index of performance. The statistical results of this study show that the fractal dimension estimated by an original method is the most relevant Roughness Parameter to describe the surface morphology after grinding or rolling. Because of this relevance, this Roughness Parameter has also to be taken into consideration in models showing the interactions between machined surfaces and an optical wave. The methodology presented in this study can be a useful tool in the quality control phase to keep under control the fabrication process Parameters of manufactured objects in industrial environments.
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the computer based bootstrap method as a tool to select a relevant surface Roughness Parameter
Wear, 2003Co-Authors: D Najjar, Maxence Bigerelle, Alain IostAbstract:The aim of this paper is to present how to make the most of the recent and powerful statistical computer-based bootstrap method (CBBM) in Roughness studies. This work shows that this statistical method can help to determine quantitatively, and without preconception, the most relevant Roughness Parameter that characterises the surface morphology of a manufactured product as far as a correlation with a particular function, property or application is concerned. The efficiency of this statistical method is illustrated in this paper describing the relationships between the brightness level and the surface Roughness of cold-rolled low carbon steel strips; the relevance of 100 or so Roughness Parameters was studied via a computer software we have been upgrading for a few years.
Shenglei Zhang - One of the best experts on this subject based on the ideXlab platform.
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Soil moisture retrieval by remote sensing and multi-year trend analysis of the soil moisture in Tibetan Plateau
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012Co-Authors: Jinyang Du, Shenglei ZhangAbstract:In this paper, a hybrid algorithm of retrieving soil moisture is developed. This method assembles the single channel algorithm (SCA) and the Qp-model based soil moisture inversion algorithm. The new algorithm does not require soil surface Roughness Parameter. The accuracy evaluation of algorithm shows that the new method can provide accurate soil moisture estimate in Tibetan Plateau (TP). Based on eight years (2003~2010) soil moisture data, multi-year changing trend of soil moisture of the TP is analyzed. The spatial pattern of soil moisture changing trend basically coincides with the trend of precipitation of the meteorological sites.
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IGARSS - Soil moisture retrieval by remote sensing and multi-year trend analysis of the soil moisture in Tibetan Plateau
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012Co-Authors: Jinyang Du, Shenglei ZhangAbstract:In this paper, a hybrid algorithm of retrieving soil moisture is developed. This method assembles the single channel algorithm (SCA) and the Qp-model based soil moisture inversion algorithm. The new algorithm does not require soil surface Roughness Parameter. The accuracy evaluation of algorithm shows that the new method can provide accurate soil moisture estimate in Tibetan Plateau (TP). Based on eight years (2003∼2010) soil moisture data, multi-year changing trend of soil moisture of the TP is analyzed. The spatial pattern of soil moisture changing trend basically coincides with the trend of precipitation of the meteorological sites.
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An improved approach for retrieving soil moisture and surface Roughness from passive microwave observation
2011 IEEE International Geoscience and Remote Sensing Symposium, 2011Co-Authors: Shenglei ZhangAbstract:A new method of retrieving soil moisture and surface Roughness Parameter concurrently is introduced in this paper. The improved approach is based on the innovated land Parameter retrieval model (LPRM) and uses a nonlinear iterative procedure to retrieve the soil moisture and surface Roughness. We incorporate the Qp model into the original LPRM, which makes up the weakness in the assumption of model. Through comparing the soil moisture retrieved with the in situ data, we evaluate the performance of the new algorithm and the root-mean-square error (rmse) is less than 0.1m3/m3.
Francesco Mattia - One of the best experts on this subject based on the ideXlab platform.
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On the soil Roughness Parameterization problem in soil moisture retrieval of bare surfaces from synthetic aperture radar
Sensors, 2008Co-Authors: Niko E C Verhoest, Jesús Álvarez-mozos, M. Susan Moran, Hans Lievens, Wolfgang Wagner, Francesco MattiaAbstract:Synthetic Aperture Radar has shown its large potential for retrieving soil moisture maps at regional scales. However, since the backscattered signal is determined by several surface characteristics, the retrieval of soil moisture is an ill-posed problem when using single configuration imagery. Unless accurate surface Roughness Parameter values are available, retrieving soil moisture from radar backscatter usually provides inaccurate estimates. The characterization of soil Roughness is not fully understood, and a large range of Roughness Parameter values can be obtained for the same surface when different measurement methodologies are used. In this paper, a literature review is made that summarizes the problems encountered when Parameterizing soil Roughness as well as the reported impact of the errors made on the retrieved soil moisture. A number of suggestions were made for resolving issues in Roughness Parameterization and studying the impact of these Roughness problems on the soil moisture retrieval accuracy and scale.
K Gururajan - One of the best experts on this subject based on the ideXlab platform.
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influence of Roughness on porous finite journal bearing with heterogeneous slip no slip surface
Tribology International, 2016Co-Authors: G K Kalavathi, P A Dinesh, K GururajanAbstract:Abstract A numerical study of effect of surface Roughness on finite porous journal bearing with heterogeneous slip/no-slip surface is presented. Generalized Reynolds type equations are derived for both types of uni-dimensional Roughness structure. The well established Christensen stochastic theory is used to study the Roughness effect. The governing differential equation can be solved by finite difference method. The effect of surface Roughness Parameter, slip Parameter, permeability Parameter and eccentricity ratio on pressure and hydrodynamic load is investigated. It has been shown that pressure and load carrying capacity increases with surface Roughness for the bearing with slip/no-slip surface.
