Analysis of a Hidden-line Algorithm

The goal for this research was to develop an efficient hiddenline algorithm for a small computer system. A hidden-line algorithm published by J .. G. Griffith was used as a basis for the research. The algorithm was successfully implemented on a mini-computer and extensive analysis and testing were done. This work showed that Griffith's algorithm was a linear growth algorithm as �compared to the complexity of the picture environment. Several enhancements were added to theoriginal algorithm to achieve even greater efficiency.Computing and Information Scienc

Development of radiofrequency pulses for fast and motion-robust brain MRI

This thesis is based on three projects and the three scientific articles that were the result of each project. Each project deals with various kinds of technical software development in the field of magnetic resonance imaging (MRI). The projects are in many ways very different, encompassing several acquisition and reconstruction strategies. However, there are at least two common denominators. The first is the projects shared the same goal of producing fast and motion robust methods. The second common denominator is that all the projects were carried out with a particular focus on the radiofrequency (RF) pulses used. The first project combined the acceleration method simultaneous multi-slice (SMS) with the acquisition method called PROPELLER. This combination was utilized to acquire motion-corrected thin-sliced reformattable T2-weighted and T1-FLAIR image volumes, thereby producing a motion robust alternative to 3D sequences. The second project analyzed the effect of the excitation RF pulse on T1-weighted images acquired with 3D echo planar imaging (EPI). It turned out that an RF pulse that reduced magnetization transfer (MT) effects significantly increased the gray/white matter contrast. The 3D EPI sequence was then used to rapidly image tumor patients after gadolinium enhancement. The third project combined PROPELLER’s retrospective motion correction with the prospective motion correction of an intelligent marker (the WRAD). With this combination, sharp T1-FLAIR images were acquired during large continuous head movements

Problemas de durabilidad de los materiales de construcción arqueológicos en ambientes acuosos y subaéreos, con aplicaciones a la restauración y conservación en Egipto y Sudán.

The main objective of the study was to identify and assess the conservation problems of the building materials of each case study and compare the aggressive impacts of each environment on the sustainability of the construction materials. Carefully, the construction materials (limestone, sandy limestone, sandstone, lime mortars, gypsum, hydraulic lime mortar/roman mortar) were selected from different archaeological sites with different environmental conditions in Egypt and Sudan (desert: Sahure?s pyramid and pyramids of Meroe; urban/agricultural: Nero/Ramses II Temple; coastal: Anfushi?s Necropolis; and fluvial: Abaton/Osiris Temple). To achieve this goal, field observations, analytical (X-ray diffraction, X-ray fluorescence, Raman spectroscopy, UV-Vis spectrometry), microscopic (binocular microscope, polarizing microscope and scanning electron microscope), mapping (AutoCAD, ArcMap 10.8, SeaDAS, QGIS), and physical and mechanical testing investigations were carried out. Furthermore, open-access satellite lenses were used for the detection and assessment of the archaeological sites and their risks, and, the deterioration patterns of each case study were recorded through decay mappings. Finally, to preserve the lime mortar surfaces, a newly synthesized nanomaterial of SiO2-TiO2 NPs/TEOS was applied and tested. The results showed the severity of each factor on the construction materials. In this sense, Sahure?s pyramid was affected mainly by climatic and environmental factors, earthquakes and the inner composition of the building materials. Nero/Ramses II Temple showed its susceptivity mainly from the salt attack which came from the contaminated sources of water around the temple. Water intrusion, earthquakes, storms, and heavy rains factors attacked Anfushi?s Necropolis severely. Abaton/Osiris Temple was decayed because of Nile water fluctuations impact and the inner weakness of the temple sandstones. In Sudan, the pyramids of Meroe were damaged because of the sand dunes and wind forces, in addition to the flooding risks. Finally, and concerning to the heritage conservation, the research exhibited the efficacy of the multifunctional 3% and 5% SiO2-TiO2 NPs/TEOS in the consolidation and improvement of the physical and mechanical ancient lime mortars

The earliest instrument : ritual power and fertility magic of the flute in Upper Paleolithic culture

textThe present study examines the earliest known musical instruments, Upper Paleolithic flutes. Flutes dating to the Upper Paleolithic period are the oldest musical instruments that have survived in the archeological record. These have been discovered at archeological sites in Europe dating from approximately 40,000 to 15,000 years ago. Although humans were most likely creating music prior to this time, the people who entered Europe approximately 40,000 years ago began to create musical instruments that have survived to the present day. This study investigates the significance and function of these instruments in Upper Paleolithic culture. Analysis of the artifacts is followed by discussions of archeological contexts, Upper Paleolithic art, ethnographic comparison, and the flute in mythology. Such diverse sources provide multiple layers of evidence regarding the role of the flute in Upper Paleolithic culture. The phallic shape of the instrument and the fact that it is played with the breath, also a symbol of life, connect the flute with the fertility of humans, plants, and animals, the cycle of life and death, and rebirth after death. There is evidence that the flute was intrinsically linked to these themes even in the Upper Paleolithic period, in which the flute was of vital significance, as it was magically imbued with the power to bestow life.Musi

Retinal Diseases: multifocal pupillographic objective perimetry, and epidemiology

My thesis entitled Retinal diseases: multifocal pupillographic objective perimtery, and epidemiology comprises two parts. First, retinal function measured with multifocal pupillographic objective perimetry (mfPOP) in neovascular AMD (nAMD) and diabetic macular oedema (DMO), and second, epidemiology of vitreoretinal diseases (VRD) in Bhutan and Nepal. The epidemiological chapters cover 1905 new VRD patients in Nepal, and 2913 in Bhutan. Those studies identified the common, preventable VRDs including: diabetic retinopathy and macular oedema, nAMD, high myopia, hypertensive retinopathy, retinal vein occlusion, retinal breaks, retinal vasculitis, retinopathy of prematurity, etc. In Nepal, females presented later than males by 9 years (p<0.0001), age or disease duration for diabetic retinopathy did not correlate with severity, presenting visual acuity (VA) was asymmetric between eyes (p<0.0001), and patients often only reported once their right (dominant) eyes had VA of 6/18 or worse. In Bhutan, females presented earlier: (p=0.003). Myopia constituted 92.1% of refractive error with myopia prevalence (MP) of 12.3%, more common among females (p=0.01) and urbanites (p=0.02). MP was highest among urban females (20.9%), followed by urban males (11.9%), rural females (6.8%), and rural males (5.2%). Logistic regression revealed that the odds of having myopia were increased by being a student (4.96 x) or professional (1.96 x), and decreased by rural living (1.75 x), all p =/< 0.038. Those diseases are treatable with complete recovery if managed early. To improve management, we address the knowledge gap in developing countries by advancing a reliable objective diagnostic method: an FDA-cleared prototype of mfPOP, the ObjectiveFIELD Analyser (OFA) (Konan Medical USA, Irvine, CA). In nAMD, the per-region central OFA sensitivities decreased and delays increased with disease severity in patients tested monthly for up to 2 years. Central sensitivity of eyes needing anti-VEGF treatment was less sensitive than in the untreated eyes by -2.23+/-0.051 dB (p<0.0002). Based on the peripheral responses we have noticed 2 types of patients: positive with peripheral hypersensitivity and longer delays than normal, and negative with peripheral hyposensitivity and shorter delays. Among the positive eyes the peripheral sensitivity increased on average by 9.88+/-4.41 dB/month (p=0.042), and the delay increased at 3.49+/-1.75 ms/month (p=0.049) before the clinical decision to treat. For the negative eyes, the peripheral sensitivity dropped, and the delay was shorter a month before the treatment by 9.38+/-3.59 (p=0.013), and a month following treatment it improved (shorter by 8.50+/-2.71 ms, p=0.004). Treatment drove subsequent responses towards normality either from the positive or negative patient condition. Importantly, changes occurred 1-3 months before treatment was indicated clinically or by other diagnostic methods. We followed Type 2 diabetes patients for up to 2 years. Reduced mean sensitivities and longer delays were seen compared to normal. Peripheral hypersensitivity and shorter delays were associated with shorter diabetes duration. Principal curve analysis showed correlation between OFA and Matrix values. Outer macular thickness correlated significantly with inner and outer OFA sensitivity and delay, all p<0.0012 with DMO, and median p=0.001 without DMO, while the inner thickness was not correlated. A mixed-effects logistic regression determined that outer thickness and OFA sensitivity contributed independently to a clinical diagnosis of DMO. Outer thickness, number of visits and male gender increased the odds of having DMO. From a practical standpoint dilation with tropicamide 1% affected per-region sensitivities for more hours than either delays or signal-to-noise ratios (SNRs). So sensitivity measurements should be considered only after 48 hours, but delays or SNRs can be measured after 8-12 hours following mydriasis with tropicamide

JPL Quarterly Technical Review, Volume 2, Number 4

Quarterly report of JPL research and developmen