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Evaluation of.Dif.erent Topographic Parameters Extracted f.om the Digital Elevation Measurements with the Use of.Geostatistical Interpolation Methods

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International Journal of.Geosciences 2023年第12期14卷 1226-1242页

作者： fahmy f. f. asal Civil Engineering Department Faculty of Engineering Menoufia University Shebin El-Kom Egypt

Gradient slope, aspect slope, prof.ling and contourlines are important topographic parameters that can be derived f.om digital elevation data obtained f.om dif.erent sources with exploitation of.dif.erent interpolation techniques. Geostatistical interpolation methods such as ordinary kriging models constitute reliable alternatives to deterministic approaches in creation of.continuous surf.ce models f.om discrete elevation data. This research aimed at extraction, analysis, and evaluation of.dif.erent terrain parameters elevation measurements with the use of.dif.erent ordinary kriging models including the linear model, the circular model, the spherical model, the exponential models, and the Gaussian model. Dif.erent ordinary kriging models under ESRI ArcView 3.3 package along with its 3D analyst and Spatial analysis extensions have been exploited in extraction of.gradient slope maps, aspect slope maps, and hillshade maps in addition to contourline maps f.om a sample of.elevation data. Visual analysis of.the gradient slope maps shows great similarities between the slope maps f.om the linear, circular, spherical, and exponential OK models, however, that f.om OK Gaussian models look very dif.erent as dif.erent sizes and arrangements of.the colour patches, ref.rring to dif.erent tones and dif.erent textures where smooth tones and smooth textures dominate the gradient slope map f.om the OK Gaussian model. Thus, gradient slope degradation and smoothing are considerably high in the gradient slope map f.om Gaussian model compared to the slope maps f.om the other f.ur OK models. Also, the mean slope in the Gaussian model records the lowest value with the lowest value of.the standard deviation of.slopes in the same map ref.ecting less structured and highly smoothed gradient slope map compared to the slope maps f.om the other OK models. Thus, similar sizes of.the colour patches and similar tones and similar texture dominate the dif.erent aspect slope maps. This is not the case i

关键词： Topographic Parameters Gradient Slope Aspect Slope Shaded Relief Contourline Prof.ling Ordinary Kriging Models

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Comparative Analysis of.the Digital Terrain Models Extracted f.om Airborne LiDAR Point Clouds Using Dif.erent f.ltering Approaches in Residential Landscapes

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Advances in Remote Sensing 2019年第2期8卷 51-75页

作者： fahmy f. f. asal Civil Engineering Department Faculty of Engineering Menoufia University Shebin El-Kom Egypt

Light Detection And Ranging (LiDAR) is a well-established active remote sensing technology that can provide accurate digital elevation measurements f.r the terrain and non-ground objects such as vegetations and buildings, etc. Non-ground objects need to be removed f.r creation of.a Digital Terrain Model (DTM) which is a continuous surf.ce representing only ground surf.ce points. This study aimed at comparative analysis of.three main f.ltering approaches f.r stripping of. non-ground objects namely;Gaussian low pass f.lter, f.cal analysis mean f.lter and DTM slope-based f.lter of.varying window sizes in creation of.a reliable DTM f.om airborne LiDAR point clouds. A sample of.LiDAR data provided by the ISPRS WG III/4 captured at Vaihingen in Germany over a pure residential area has been used in the analysis. Visual analysis has indicated that Gaussian low pass f.lter has given blurred DTMs of.attenuated high-f.equency objects and emphasized low-f.equency objects while it has achieved improved removal of.non-ground object at larger window sizes. f.cal analysis mean f.lter has shown better removal of.nonground objects compared to Gaussian low pass f.lter especially at large window sizes where details of.non-ground objects almost have diminished in the DTMs f.om window sizes of.25 × 25 and greater. DTM slope-based f.lter has created bare earth models that have been f.ll of.gabs at the positions of.the non-ground objects where the sizes and numbers of.that gabs have increased with increasing the window sizes of.f.lter. Those gaps have been closed through exploitation of.the spline interpolation method in order to get continuous surf.ce representing bare earth landscape. Comparative analysis has shown that the minimum elevations of.the DTMs increase with increasing the f.lter widow sizes till 21 × 21 and 31 × 31 f.r the Gaussian low pass f.lter and the f.cal analysis mean f.lter respectively. On the other hand, the DTM slope-based f.lter has kept the minimum elevation of.th

关键词： DSM/DEM/DTM Airborne LiDAR Point Clouds DSM f.ltering Gaussian Low Pass f.lter f.cal Analysis Mean f.lter DTM Slope-Based f.lter Removal of Non-Ground Objects

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Creation and Analysis of.Earth’s Surf.ce Roughness Maps f.om Airborne LiDAR Measurements in Downtown Urban Landscape

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Journal of.Geographic Inf.rmation System 2019年第2期11卷 212-238页

作者： fahmy f. f. asal Civil Engineering Department Faculty of Engineering Menoufia University Shebin El-Kom Egypt

The Earth’s surf.ce roughness constitutes an important parameter in terrain analysis f.r studying dif.erent environmental and engineering problems. Authors gave dif.erent def.nitions and measures f.r the earth’s surf.ce roughness that usually depend on exploitation of.digital elevation data f.r its reliable determination. This research aimed at exploring the dif.erent approaches f.r def.ning and extraction of.the Earth’s surf.ce roughness f.om Airborne LiDAR Measurements. It also aimed at evaluating the ef.ects of.the window size of.the standard deviation f.lter on the created roughness maps in downtown landscapes using three known approaches namely;standard deviation f.ltering of.the Digital Elevation Model (DEM), standard deviation f.ltering of.the slope gradient model and standard deviation f.ltering of.the prof.le curvature model. In this context, dif.erent roughness maps have been created f.om Airborne LiDAR measurements of.the City of.Toronto, Canada using the three f.ltering approaches with varying window sizes. Visual analysis has shown color tones of.small roughness values with smooth textures dominate the roughness maps f.om small window sizes of.the standard deviation f.lter, however, increasing the window sizes has produced wider variations of.the color tones and rougher texture roughness maps. The standard deviations and ranges of.the roughness maps f.om LiDAR DEM have increased due to increasing the f.lter window size while the skewness and kurtosis have decreased due to increasing the window size, indicating that the roughness maps f.om larger window sizes are statistically more symmetrical and more consistent. Thus, kurtosis has decreased by 53% and 82% due to increasing the window size to 7 × 7 and 15 × 15 respectively. The standard deviations of.the roughness maps f.om the slope gradient model have increased due to increasing the window size till 15 × 15 while they have decreased with more increases. However, skewness has decreased due to increasin

关键词： Surf.ce Roughness Urban Landscape Airborne LiDAR DSM/DEM/DTM Slope Gradient Prof.le Curvature Standard Deviation f.ltering Spatial Analysis

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Comparative Analysis of.the Digital Terrain Models Extracted f.om Airborne LiDAR Point Clouds Using Dif.erent f.ltering Approaches in Residential Landscapes

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Advances in Remote Sensing（遥感技术进展） 2019年第2期

作者： fahmy f. f. asal

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Adaptive Hybrid Bivariate Double Density Discrete and Complex Wavelet f.r Image Denoising

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Journal of.Computer and Communications 2023年第2期11卷 39-56页

作者： Gamal fahmy Mamdouh f. fahmy Omar fahmy f.culty of.Computer Science and Engineering Galala University Al Galala Egypt Electrical Engineering Dept. Assiut University Assiut Egypt Electrical Engineering Dept. Badr University Cairo Egypt

Image denoising is an important step in eliminating any noise impact in any image transmission process. Recently we presented two approaches f.r Bivariate based image denoising. They were Double Density Discrete Wavelet Transf.rm (DD DWT) and Double Density Dual Tree Complex Wavelet Transf.rm (DD CWT). In both techniques we decomposed noisy images with either DD DWT or DD CWT decompositions and then applied the Bivariate based denoising technique f.r noise removal. In this paper we propose an adaptive hybrid technique f.r Bivariate based image denoising that is based on the synthesis of.DD-DWT bands or DD-CWT bands but with dif.erent weights, to deliver enhanced image f.atures with less denoising impact especially around image edges, which is the most ef.ected by noisy transmission channels. This proposed technique has been also enhanced by edge sharpening and Eigen analysis, as two separate stages. Simulation result comparisons have been perf.rmed between the proposed hybrid band adaptive DD-DWT and DD-CWT technique and the two primary techniques DD-DWT, DD- CWT, as well as other superior literature techniques such the original bivariate denoising technique with both original Complex Wavelet Transf.rm and Double Density decompositions. This work in specif.c compares between Double Density DWT and Double Density CWT decompositions, proposes new f.lter design that suits each of.them and proposes a hybrid technique between as will be shown.

关键词： Complex Wavelet Image Deniosing Double Density Wavelets

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A New f.st Iterative Blind Deconvolution Algorithm

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Journal of.Signal and Inf.rmation Processing 2012年第1期3卷 98-108页

作者： Mamdouh f. fahmy Gamal M. Abdel Raheem Usama S. Mohamed Omar f. fahmy Department Electrical Engineering Assiut University Assiut Egypt Department of.Electrical Engineering Future University Cairo Egypt

Successf.l blind image deconvolution algorithms require the exact estimation of.the Point Spread f.nction size, PSf. In the absence of.any priori inf.rmation about the imagery system and the true image, this estimation is normally done by trial and error experimentation, until an acceptable restored image quality is obtained. This paper, presents an exact estimation of.the PSf.size, which yields the optimum restored image quality f.r both noisy and noiseless images. It is based on evaluating the detail energy of.the wave packet decomposition of.the blurred image. The minimum detail energies occur at the optimum PSf.size. Having accurately estimated the PSf. the paper also proposes a f.st double updating algorithm f.r improving the quality of.the restored image. This is achieved by the least squares minimization of.a system of.linear equations that minimizes some error f.nctions derived f.om the blurred image. Moreover, a technique is also proposed to improve the sharpness of.the deconvolved images, by constrained maximization of.some of.the detail wavelet packet energies. Simulation results of.several examples have verif.ed that the proposed technique manages to yield a sharper image with higher PSNR than classical approaches.

关键词： Blind Image Deconvolution Image Enhancement

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Relationship between Cerebral Imaging and Executive f.nctions in Egyptian Elderly

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Advances in Aging Research 2014年第2期3卷 95-101页

作者： Motassem S. Amer Nagia A. fahmy Sarah A. Hamza Eman f. Tash Mohammmad A. A. Allaboudy Department of.Geriatrics and Gerontology Faculty of Medicine Ain Shams University Cairo Egypt Department of.Neuropsychiatry Faculty of Medicine Ain Shams University Cairo Egypt

This study aimed at assessing the relationship between executive f.nctions and lef. sided hemiplegia due to non hemorrhagic supratentorial inf.rction in elderly Egyptians. It is considered a case control study which was conducted among 90 elderly participants, who were divided into two groups: a case group, 45 cases with cerebral inf.rctions of.6 months duration or more, and a control group who did not have previous cerebral inf.rctions. Both groups were selected f.om Ain shams University Hospital. Each participant was subjected to comprehensive geriatric assessment, executive f.nctions assessment using, block design test, digit span, letter verbal f.uency test, animal verbal f.uency test and clock drawing test, and then a Computed Tomography (CT) brain was perf.rmed. It was f.und that cases were suf.ering f.om more f.nctional impairment than controls, and have had signif.cant lower scores in Mini Mental Status Examination (MMSE) (P f.cant dif.erence was f.und between both groups as regards perf.rmance of.executive f.nction tests (P f.cant ef.ect of.Parietal lobe inf.rctions was f.und on Block Design Test, Digit Span Test, Animal Verbal f.uency and Clock Drawing Test (P value f.cant dif.erence between cases and controls as regards their perf.rmance in cognitive and executive f.nction tests.

关键词： Executive f.nctions Cerebral Inf.rctions Elderly

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Evaluation of.Dif.erent Topographic Parameters Extracted f.om the Digital Elevation Measurements with the Use of.Geostatistical Interpolation Methods

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International Journal of.Geosciences（地球科学国际期刊） 2023年第12期

作者： fahmy f.f.asal

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A New f.st Iterative Blind Deconvolution Algorithm

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Journal of.Signal and Inf.rmation Processing（信号与信息处理） 2012年第1期

作者： Mamdouh f. fahmy Gamal M. Abdel Raheem Usama S. Mohamed Omar f. fahmy

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f.OM A SYSTEMIC APPROACH IN TEACHING AND LEARNING CHEMISTRY (SATLC) TO BENIGN ANALYSIS

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化学教育 2002年第12期23卷 26-33页

作者： A.f.M.fahmy M.S.A.Hamza H.A.A.Medien W.G.Hanna M.Abdel-Sabour J.J.Lagowski Department of.Chemistry Faculty of Scienceand Science Education Center(SEC)Ain Shams UniversityAbbassiaCairoEgypt Department of.Chemistry and Biochem.The University of.Texas at Austin TX78712.

The Systemic Approach in Teaching and Learning Chemistry(SATLC)was established in 1997[1-3].Our interest in develo—ping the SATL strategy arose f.om the recognition of.the increasing globalization of.a wide spectrum of.human activities such as economics,media,politics,and *** is our attempt to provide the student with a global view of.his/her studies of.chemistry.

关键词： Teaching and Learning human activities global view

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