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Search Results: 1 - 10 of 144649 matches for " Fahmy F. F. Asal "
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Creation and Analysis of Earth’s Surface Roughness Maps from Airborne LiDAR Measurements in Downtown Urban Landscape  [PDF]
Fahmy F. F. Asal
Journal of Geographic Information System (JGIS) , 2019, DOI: 10.4236/jgis.2019.112015
Abstract: The Earth’s surface roughness constitutes an important parameter in terrain analysis for studying different environmental and engineering problems. Authors gave different definitions and measures for the earth’s surface roughness that usually depend on exploitation of digital elevation data for its reliable determination. This research aimed at exploring the different approaches for defining and extraction of the Earth’s surface roughness from Airborne LiDAR Measurements. It also aimed at evaluating the effects of the window size of the standard deviation filter on the created roughness maps in downtown landscapes using three known approaches namely; standard deviation filtering of the Digital Elevation Model (DEM), standard deviation filtering of the slope gradient model and standard deviation filtering of the profile curvature model. In this context, different roughness maps have been created from Airborne LiDAR measurements of the City of Toronto, Canada using the three filtering approaches with varying window sizes. Visual analysis has shown color tones of small roughness values with smooth textures dominate the roughness maps from small window sizes of the standard deviation filter, 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 from LiDAR DEM have increased due to increasing the filter window size while the skewness and kurtosis have decreased due to increasing the window size, indicating that the roughness maps from 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 from 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 increasing the window size till 15 × 15 and the kurtosis has decreased with higher rate till window size of 11 × 11. In the roughness maps from the profile curvature model, the ranges and skewness have decreased by 93.6% and 82.6% respectively due to increasing the window size to 15 × 15 while, kurtosis has decreased by 58.6%, 76.3% and 93.76% due to increases in the filter window size to 5 × 5, 7 × 7 and 15 × 15 respectively.
Comparative Analysis of the Digital Terrain Models Extracted from Airborne LiDAR Point Clouds Using Different Filtering Approaches in Residential Landscapes  [PDF]
Fahmy F. F. Asal
Advances in Remote Sensing (ARS) , 2019, DOI: 10.4236/ars.2019.82004

Light Detection And Ranging (LiDAR) is a well-established active remote sensing technology that can provide accurate digital elevation measurements for the terrain and non-ground objects such as vegetations and buildings, etc. Non-ground objects need to be removed for creation of a Digital Terrain Model (DTM) which is a continuous surface representing only ground surface points. This study aimed at comparative analysis of three main filtering approaches for stripping off non-ground objects namely; Gaussian low pass filter, focal analysis mean filter and DTM slope-based filter of varying window sizes in creation of a reliable DTM from 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 filter has given blurred DTMs of attenuated high-frequency objects and emphasized low-frequency objects while it has achieved improved removal of non-ground object at larger window sizes. Focal analysis mean filter has shown better removal of nonground objects compared to Gaussian low pass filter especially at large window sizes where details of non-ground objects almost have diminished in the DTMs from window sizes of 25 × 25 and greater. DTM slope-based filter has created bare earth models that have been full 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 filter. Those gaps have been closed through exploitation of the spline interpolation method in order to get continuous surface representing bare earth landscape. Comparative analysis has shown that the minimum elevations of the DTMs increase with increasing the filter widow sizes till 21 × 21 and 31 × 31 for the Gaussian low pass filter and the focal analysis mean filter respectively. On the other hand, the DTM slope-based filter has kept the minimum

A New Fast Iterative Blind Deconvolution Algorithm  [PDF]
Mamdouh F. Fahmy, Gamal M. Abdel Raheem, Usama S. Mohamed, Omar F. Fahmy
Journal of Signal and Information Processing (JSIP) , 2012, DOI: 10.4236/jsip.2012.31013
Abstract: Successful blind image deconvolution algorithms require the exact estimation of the Point Spread Function size, PSF. In the absence of any priori information 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 for 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 fast double updating algorithm for 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 functions derived from 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 verified that the proposed technique manages to yield a sharper image with higher PSNR than classical approaches.
Nonblind and Quasiblind Natural Preserve Transform Watermarking
G. Fahmy,M. F. Fahmy,U. S. Mohammed
EURASIP Journal on Advances in Signal Processing , 2010, DOI: 10.1155/2010/452548
Abstract: This paper describes a new image watermarking technique based on the Natural Preserving Transform (NPT). The proposed watermarking scheme uses NPT to encode a gray scale watermarking logo image or text, into a host image at any location. NPT brings a unique feature which is uniformly distributing the logo across the host image in an imperceptible manner. The contribution of this paper lies is presenting two efficient nonblind and quasiblind watermark extraction techniques. In the quasiblind case, the extraction algorithm requires little information about the original image that is already conveyed by the watermarked image. Moreover, the proposed scheme does not introduce visual quality degradation into the host image while still being able to extract a logo with a relatively large amount of data. The performance and robustness of the proposed technique are tested by applying common image-processing operations such as cropping, noise degradation, and compression. A quantitative measure is proposed to objectify performance; under this measure, the proposed technique outperforms most of the recent techniques in most cases. We also implemented the proposed technique on a hardware platform, digital signal processor (DSK 6713). Results are illustrated to show the effectiveness of the proposed technique, in different noisy environments.
Relationship between Cerebral Imaging and Executive Functions in Egyptian Elderly  [PDF]
Motassem S. Amer, Nagia A. Fahmy, Sarah A. Hamza, Eman F. Tash, Mohammmad A. A. Allaboudy
Advances in Aging Research (AAR) , 2014, DOI: 10.4236/aar.2014.32015

This study aimed at assessing the relationship between executive functions and left sided hemiplegia due to non hemorrhagic supratentorial infarction 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 infarctions of 6 months duration or more, and a control group who did not have previous cerebral infarctions. Both groups were selected from Ain shams University Hospital. Each participant was subjected to comprehensive geriatric assessment, executive functions assessment using, block design test, digit span, letter verbal fluency test, animal verbal fluency test and clock drawing test, and then a Computed Tomography (CT) brain was performed. It was found that cases were suffering from more functional impairment than controls, and have had significant lower scores in Mini Mental Status Examination (MMSE) (P < 0.01). Significant difference was found between both groups as regards performance of executive function tests (P < 0.05). Significant effect of Parietal lobe infarctions was found on Block Design Test, Digit Span Test, Animal Verbal Fluency and Clock Drawing Test (P value < 0.05). Conclusion: There was a significant difference between cases and controls as regards their performance in cognitive and executive function tests.

Primary nasopharyngeal interdigitating dendritic cell tumor presentation and response to radiation therapy
Neal E. Dunlap,Randell L. Woodford,Asal N. Shoushtari,James F. Reibel
Rare Tumors , 2010, DOI: 10.4081/rt.2010.e9
Abstract: We report the case of a primary nasopharyngeal interdigitating dendritic cell tumor (IDDCT). A 25-year old male presented with bilateral decreased hearing, double vision, and ataxia. Flexible nasopharyngoscopy reviewed a large mass obstructing and filling the entire nasopharynx. MRI and PET-CT confirmed the presence of the primary tumor and demonstrated bilateral cervical lymphadenopathy. Biopsy of the nasopharynx revealed a hematolymphoid neoplasm with dendritic cell differentiation, most consistent with an IDDCT. The lesion was unresectable. The patient was treated with definitive radiotherapy to 66 Gy to the primary tumor and 50 Gy to the bilateral cervical lymphatics using an IMRT technique. A complete response was achieved and the patient remains disease free at the primary site 23 months after completion of radiotherapy.
Thermal Equilibrium as an Initial State for Quantum Computation by NMR
Amr F. Fahmy,Raimund Marx,Wolfgang Bermel,Steffen J. Glaser
Physics , 2007, DOI: 10.1103/PhysRevA.78.022317
Abstract: We present a method of using a nuclear magnetic resonance computer to solve the Deutsch-Jozsa problem in which: (1) the number of molecules in the NMR sample is irrelevant to the number of qubits available to an NMR quantum computer, and (2) the initial state is chosen to be the state of thermal equilibrium, thereby avoiding the preparation of pseudopure states and the resulting exponential loss of signal as the number of qubits increases. The algorithm is described along with its experimental implementation using four active qubits. As expected, measured spectra demonstrate a clear distinction between constant and balanced functions.
Professional practices and perception towards rational use of medicines according to WHO methodology in United Arab Emirates
Abdul Rasool,Bazigha K.; Fahmy,Sahar A.; Abu-Gharbieh,Eman F.; Ali,Heyam S.;
Pharmacy Practice (Internet) , 2010, DOI: 10.4321/S1886-36552010000100009
Abstract: inappropriate prescribing reduces the quality of medical care and leads to a waste of resources. no study has been reported concerning rational drug use in united arab emirates, uae, recently. objectives: 1. assessing patterns of use and defining problems regarding the rational drug use. 2. setting baseline situational analysis study for practices in the health care system relevant to drug use. method: a descriptive pilot study, consisting of pharmacists, physicians and patients (100 of each of category) from four private hospitals, (12) medical clinics, (80) community pharmacies in addition to 150 prescriptions. a questionnaire of three sections was designed to include who indicators regarding patients, facility and prescribing patterns that are relevant to rational drug use was carried out in four emirates of the uae in the period december 2008-febreuary 2009. results: consultation and dispensing times were 10 (sd=2.75) min and 68 (sd=9.7) seconds, respectively. average no. of drugs per prescription was (2.9 + 0.97), % of prescriptions using generic name (7.35%), % of antibiotic containing prescriptions (31.1%), % of injection containing prescriptions (2.9%), adherence to standard treatment protocols (46%), adherence to the essential drug list (64%), patient′s knowledge of correct dosage (55%), adequately labeled drugs (45%), patient′s information (65%). conclusions: several areas of deficiency in rational drug use had been defined in the private sector through uae that can be remedied through adopting several strategies such as adherence to national standard treatment guidelines and essential drug list based on treatments of choice, interaction between health care system and providing drugs information to consumers.
Extended Immunization of Rats using Microencapsulated Cobra Venom
H.F. Salem,Aly Fahmy,Ahmed M.A. Ali
British Journal of Pharmacology and Toxicology , 2011,
Abstract: Production of a vaccine with an extended release kinetic and with a high immunization response has an economic value in the third world countries. In this study, production and evaluation of bovine serum albumin microspheres that are incorporating cobra venom were carried out. The microcapsules were prepared using modified emulsification-polymerization technique. They were evaluated for their size using photon correlation spectroscopy and for their morphology using scanning electron microscopy. The release kinetics of the venom from the chosen formula was following Higushi model with r2 >0.97. The average microsphere size of the best formula was 5.6 :m and the encapsulation efficiency approached 82%. The pharmacokinetic parameters of the microencapsulated cobra venom showed a significant difference from the free venom formulations in terms o f prolonged stimulation of in-vivo immune response (production of antibodies). The method of preparation and evaluation of microspheres were characterized by being easy to perform, yielding high entrapment efficiency and maximum induction of immune response, which enables availability of a safe, effective and economic vaccine.
Quercetin Protects against Diabetes-Induced Exaggerated Vasoconstriction in Rats: Effect on Low Grade Inflammation
Mona F. Mahmoud, Noura A. Hassan, Hany M. El Bassossy, Ahmed Fahmy
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063784
Abstract: Vascular complications are the leading cause of morbidity and mortality in patients with diabetes. Quercetin is an important flavonoid with antioxidant and anti-inflammatory activity. Here, the effect of quercetin on diabetes-induced exaggerated vasoconstriction in insulin deficient and insulin resistant rat models was investigated. Insulin deficiency was induced by streptozotocin while, insulin resistance by fructose. Rats were left 8 weeks or 12 weeks after STZ or fructose administration respectively. Quercetin was daily administered in the last 6 weeks. Then, tail blood pressure (BP) was recorded in conscious animals; concentration-response curves for phenylephrine (PE) and KCl were studied in thoracic aorta rings. Non-fasting blood glucose level, serum insulin level, insulin resistance index, serum tumour necrosis factor-α (TNF-α) and serum C-reactive protein (CRP) were determined. Nuclear transcription factor-κB (NF-κB) was assessed by immunofluorescence technique. Histopathological examination was also performed. The results showed that quercetin protected against diabetes-induced exaggerated vasoconstriction and reduced the elevated blood pressure. In addition, quercetin inhibited diabetes associated adventitial leukocyte infiltration, endothelial pyknosis and increased collagen deposition. These effects were accompanied with reduction in serum level of both TNF-α and CRP and inhibition of aortic NF-κB by quercetin in both models of diabetes. On the other hand, quercetin did not affect glucose level in any of the used diabetic models. This suggests that the protective effect of quercetin is mediated by its anti-inflammatory effect rather than its metabolic effects. In summary, quercetin is potential candidate to prevent diabetic vascular complications in both insulin deficiency and resistance via its inhibitory effect on inflammatory pathways especially NF-κB signaling.
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