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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
441

Automatické generování umelých XML dokumentu / Automatic Generation of Synthetic XML Documents

Betík, Roman January 2013 (has links)
The aim of this thesis is to research the current possibilities and limitations of automatic generation of synthetic XML documents. The first part of the work discusses the properties of the most used XML data generators and compares them to each other. The next part of the thesis proposes an algorithm for XML data generation which focuses on subset of the main XML data characteristics (number of elements, number of attributes, fan-out, mixed contents etc.). The main target of the algorithm is to generate XML documents using a set of settings which are easy to understand. The last part of the work compares the proposed solution with the existing ones. The comparison focuses on how easy it is to generate XML documents, what structures can be created and finally it compares properties of the similar XML data created using different XML data generators. Powered by TCPDF (www.tcpdf.org)
442

Optimizing coverage and revisit time in sparse military satellite constellations a comparison of traditional approaches and genetic algorithms

Parish, Jason A. 09 1900 (has links)
Sparse military satellite constellations were designed using two methods: a traditional approach and a genetic algorithm. One of the traditional constellation designs was the Discoverer II space based radar. Discoverer II was an 8 plane, 24 satellite, Low Earth Orbit (LEO), Walker constellation designed to provide high-range resolution ground moving target indication (HRR-GMTI), synthetic aperture radar (SAR) imaging and high resolution digital terrain mapping. The traditional method designed 9-ball, 12-ball, 18-ball, and 24- ball Walker constellations. The genetic algorithm created constellations by deriving a phenotype from a triploid genotype encoding of orbital elements. The performance of both design methods were compared using a computer simulation. The fitness of each constellation was calculated using maximum gap time, maximum revisit time, and percent coverage. The goal was to determine if one design method would consistently outperform the other. The genetic algorithm offered a fitness improvement over traditional constellation design methods in all cases except the 24-ball constellation where it demonstrated comparable results. The genetic algorithm improvement over the traditional constellations increased as the number of satellites per constellation decreased. A derived equation related revisit time to the number of ship tracks maintained. / US Navy (USN) author.
443

Etude de la répartition géochimique du cuivre dans les sols du vignoble champenois : approche par modèles synthétiques de complexité croissante

Proffit, Sylvain 09 December 2011 (has links)
Ces travaux s’inscrivent dans le cadre du contrat d’objectifs AQUAL dont le but est la lutte contre les pollutions diffuses en milieu rural. Ils portent sur la compréhension des mécanismes de rétention du cuivre dans les sols viticoles. Afin de s’affranchir de la complexité des sols, sept constituants ont été sélectionnés (quartz,calcite, kaolinite, matière organique, goethite, ferrihydrite et birnessite). Le comportement du cuivre a été étudié sur les constituants seuls puis dans des mélanges de complexité croissante, afin d’évaluer l’implication de chacun d’entre eux, en fonction du pH et de la concentration en cuivre. L’influence du vieillissement et de la concentration sur la répartition géochimique du cuivre a ensuite été évaluée dans des sols synthétiques et naturels contaminés. L’ensemble des résultats a été obtenu grâce à la combinaison de plusieurs techniques permettant d’obtenir des informations complémentaires aux échelles macroscopique, microscopique (STEM-EDX et μ-XRF) et moléculaire (XANES).Les résultats montrent d’une part, que les principaux constituants responsables de la rétention du cuivre sont la matière organique et les oxydes de fer et de manganèse et d’autre part, que l’existence d’interactions organo-minérales influe significativement sur la rétention du cuivre. Lacombinaison d’expériences de sorption et d’extractions séquentielles a permis de mettre en évidence que les processus de rétention du cuivre se produisant dans le sol naturel peuvent être mimés dans un sol synthétique, ce dernier pouvant ainsi être utilisé comme modèle. / This work is a part of the AQUAL research program which aims to strive against diffuse pollution in rural environment. It deals with the understanding of copper retention mechanisms in vineyard soils.To overcome the soil complexity, seven constituents were selected (quartz, calcite, kaolinite,organic matter, goethite, ferrihydrite and birnessite). The copper behavior was firstly studied on the single constituents, then on increasing complexity constituents mixtures in order to assess their implication as a function of pH and copper concentration. The influence of aging time and copper concentration was evaluated on the copper geochemical partitioning in synthetic and natural soils.Conclusion could be drawn by combination of several techniques providing complementary information at macroscopic, microscopic (STEM-EDX, μ-XRF) and molecular (XANES) scales.The results showed on the one hand, that organic matter and iron and manganese oxides are the main constituents involved in copper retention and on the other hand, that the presence of organo-mineral interactions also significantly influences the copper retention. Sorption experiments combined with sequential extractions emphasized that copper retention processes occurring in a natural soil can be mimicked in a synthetic soil which could then be used as a model.
444

Strategic Oxidative Dearomatization - Rearomatization Cascades in the Synthesis of Aromatic and Heteroaromatic Synthons

Vitaku, Edon, Vitaku, Edon January 2016 (has links)
Four new synthetic methods employing an oxidative dearomatization - rearomatization strategy are presented. In Chapter 2, a new oxidative dearomatization - radical cyclization - rearomatization approach to form fused oxygen-containing heterocycles is presented. Origins, design, reaction, and optimizations are discussed. In Chapter 3, meta-selective alkylation of catechol mono-ethers is described employing an oxidative dearomatization - radical addition - rearomatization approach using trialkylboranes as source of alkyl radicals. In Chapter 4, a metal-free method to synthesize fluorinated indoles from aniline starting materials is described. Chapter 5 lays the groundwork for para-selective functionalization of catechol mono-ethers. Chapters 6 and 7 highlight the work related to pharmaceutical drug analyses. Chapter 6 presents the FDA approved drugs organized in Disease Focused Posters. Chapter 7.1 and 7.2 present the drug analysis of Sulfur- and Fluorine-Containing Drugs, and Nitrogen-Heterocycle Containing Drugs, respectively.
445

Altronegest influences growth, reproductive, and carcass traits in male swine

Kluber, Edward Frank. January 1986 (has links)
Call number: LD2668 .T4 1986 K58 / Master of Science / Animal Sciences and Industry
446

Interferometric Synthetic Aperture Sonar Signal Processing for Autonomous Underwater Vehicles Operating Shallow Water

Giardina, Patricia E 15 December 2012 (has links)
The goal of the research was to develop best practices for image signal processing method for InSAS systems for bathymetric height determination. Improvements over existing techniques comes from the fusion of Chirp-Scaling a phase preserving beamforming techniques to form a SAS image, an interferometric Vernier method to unwrap the phase; and confirming the direction of arrival with the MUltiple SIgnal Channel (MUSIC) estimation technique. The fusion of Chirp-Scaling, Vernier, and MUSIC lead to the stability in the bathymetric height measurement, and improvements in resolution. This method is computationally faster, and used less memory then existing techniques.
447

Ferromagnetic Resonance Studies of Coupled Magnetic Systems

Adams, Daniel J. 13 May 2016 (has links)
The high-frequency properties of coupled magnetic systems have been investigated using vector network analyzer ferromagnetic resonance (VNA-FMR) spectroscopy. SAF structures consist of two ferromagnetic layers separated by a non-magnetic spacer, coupled through the indirect exchange interaction. The ferromagnetic layers of our samples were composed of FeCoB separated by a layer of Ru. The thickness of Ru was varied in the range of 8 to 18 Å among the samples studied. Antiferromagnetic coupling can be quickly identified by the major hysteresis loop (MHL). A new way of displaying FMR data for these trilayer samples is presented which completely preserves the anisotropy effects while fully characterizing the angular dependence of FMR. The advantage of our representation is that the high-frequency data can be easily compared to the static switching behavior at any angle obtained through susceptibility measurements. Ferromagnetic resonance; Coupled; Synthetic antiferromagnet; Magnetization switching
448

On the estimation of physical roughness of sea ice in the Canadian Arctic archipelago using synthetic aperture radar

Cafarella, Silvie 29 August 2019 (has links)
Sea ice surface roughness is a geophysical property which can be defined and quantified on a variety scales, and consequently affects processes across various scales. The sea ice surface roughness influences various mass, gas, and energy fluxes across the ocean-sea ice-atmosphere interface. Utilizing synthetic aperture radar (SAR) data to understand and map sea ice roughness is an active area of research. This thesis provides new techniques for the estimation of sea ice surface roughness in the Canadian Arctic Archipelago using synthetic aperture radar (SAR). Estimating and isolating sea ice surface properties from SAR imagery is complicated as there are a number of sea ice and sensor properties that influence the backscattered energy. There is increased difficulty in the melting season due to the presence of melt ponds on the surface, which can often inhibit interactions from the sensor to the sea ice surface as shorter microwaves cannot penetrate through the melt water. An object-based image analysis is here used to quantitatively link the winter first-year sea ice surface roughness to C-band RADARSAT-2 and L-band ALOS-2 PALSAR-2 SAR backscatter measured at two periods: winter (pre-melt) and advanced melt. Since the sea ice in our study area, the Canadian Arctic Archipelago, is landfast, the same ice can be imaged using SAR after the surface roughness measurements are established. Strong correlations between winter measured surface roughness, and C- and L-band SAR backscatter acquired during both the winter and advanced melt periods are observed. Results for winter indicate: (1) C-band HH-polarization backscatter is correlated with roughness (r=0.86) at a shallow incidence angle; and (2) L-band HH- and VV-polarization backscatter is correlated with roughness (r=0.82) at a moderate incidence angle. Results for advanced melt indicate: (1) C-band HV/HH polarization ratio is correlated with roughness (r=-0.83) at shallow incidence angle; (2) C-band HH-polarization backscatter is correlated with roughness (r=0.84) at shallow incidence angle for deformed first-year ice only; and (3) L-band HH-polarization backscatter is correlated with roughness (r=0.79) at moderate incidence angle. Retrieval models for surface roughness are developed and applied to the imagery to demonstrate the utility of SAR for mapping roughness, also as a proxy for deformation state, with a best case RMSE of 5 mm in the winter, and 8 mm during the advanced melt. / Graduate
449

Investigation of electronic properties of high purity synthetic single crystal type IIa diamond for electronic applications

Costa, A.M.O.D. da 19 June 2008 (has links)
Abstract A range of di®erent high-quality single crystal diamonds synthesized under high pressure and high temperature (HPHT) conditions have been studied in view of their potential as candidates for specialized electronic devices with emphasis on particle detectors. The studies incorporated a long range of spectroscopic and electronic characterization techniques. Special attention was given to electronic properties and device performance re- lated to the electrical contacts applied, the type and the concentration of impur- ities and the crystallographic defects present. The electronic response of a dia- mond detector as far as impurities are concerned is predominantly determined by the single substitutional nitrogen (SSN) and boron acceptors. Di®erent tech- niques were used to assess the role of such impurities in the diamond crystals stud- ied, as well as to study the dynamics due to the interaction of such impurities with each other (compensation). Hence, the electron spin resonance (ESR) and the current-deep level transient spectroscopy (I-DLTS) techniques were used in this re- spect to extract the information concerning activation energies, nitrogen-boron dy- namics, and the nitrogen and boron concentrations. ii iii It was found that the SSN content was below 1013 cm¡3 with this result giving the approximate concentration of boron acceptors, being the same value as of that of the SSN, or slightly above. Maximum activation energies of boron acceptors were extracted from three di®erent regions in the bulk of the diamond. The values were approximately 0.311 eV § 0.0027 eV in the center region, 0.308 eV § 0.007 eV in the intermediate region and 0.29 eV § 0.007 eV at the edge region, respectively. The maximum activation energy when boron is fully compensated is about 0.37 eV. Properties of ohmic and Schottky contacts as a function of concentration of SSN and boron acceptors were investigated using Current-Voltage characteristic and photo- current measurements. Di®erent surface treatment conditions and di®erent types of diamonds (IIa, IIb and Ib) were used. Electronic properties as a function of contacts were assessed for high purity synthetic type IIa diamond detector, incorporating a time of °ight (TOF) UV laser set-up. The maximum hole collection distance at room temperature was found to be 91.00 cm, the maximum transient time for holes was about 1.00 ms and the e±ciency was approximately 41%, with contacts made of Ti/Pt/Au-Ru. When Ru-Ru contacts are applied, the maximum hole mobility and the velocity were extracted at room temperature to be about 17963.44 cm2V¡1s¡1 and 5.02 £107 cms¡1, respectively, and the e±ciency of the device is about 30%. The maximum applied external electric ¯elds with Ru-Ru contacts were increased to about 1.32 times that at low temperature and to about 1.84 times that at room temperature. iv Large signals generated by ®-particles from 228Th were obtained without using amp- li¯cation. However, a full analysis of the pulse was not possible due to the narrow bandwidth of the electronic probes used. In a detector made of type Ib diamond, with SSN concentrations of about 50 ppm, it was found that regions in the bulk exhibiting better charge collection properties contained small concentrations of uncompensated boron impurity. On the other hand, the di®erence in the concentrations of SSN between the two type Ib diamonds, with about 50 ppm and about 200 ppm of SSN concentrations, respectively, resulted in approximately 70 ps di®erence in the transit time between two detectors made of these diamonds. Keywords: Synthetic diamond, detector, HPHT, type Ib, type IIa, single substitutional ni- trogen, SSN, ESR, ARP, I-DLTS, metallization, uncompensated boron impurity, crystallographic defects, rise and decay times, charge carrier life time, charge carrier mobility, carrier mean free path , charge collection distance, carrier Schubweg.
450

Investigation of nanoscale reinforcement into textile polymers

Unknown Date (has links)
A dual inclusion strategy for textile polymers has been investigated to increase elastic energy storage capacity of fibers used in high velocity impact applications. Commercial fibers such as Spectra and Dyneema are made from ultra high molecular weight polyethylene (UHMWPE). Dynamic elastic energy of these fibers is still low therefore limiting their wholesale application without a secondary metallic or ceramic component. The idea in this investigation is to develop methodologies so that the elastic energy of polyethylene based fibers can be increased by several folds. This would allow manufacturing of an all-fabric system for high impact applications. The dual inclusion consists of a polymer phase and a nanoscale inorganic phase to polyethylene. The polymer phase was nylon-6 and the inorganic phase was carbon nanotubes (CNTs). Nylon-6 was blended as a minor phase into UHMWPE and was chosen because of its large fracture strain - almost one order higher than that of UHMWPE. On the other hand, CNTs with their very high strength, modulus, and aspect ratio, contributed to sharing of load and sliding of polymer interfaces as they aligned during extrusion and strain hardening processes. A solution spinning process was developed to produce UHMWPE filaments reinforced with CNTs and nylon-6. The procedure involved dispersing of CNTs into paraffin oil through sonication followed by dissolving polymers into paraffin-CNT solution using a homogenizer. The admixture was fed into a single screw extruder for melt mixing and extrusion through an orifice. The extrudate was rinsed via a hexane bath, stabilized through a heater, and then drawn into a filament winder with controlled stretching. In the next step, the as produced filaments were strain-hardened through repeated loading unloading cycles under tension. / Neat and reinforced filaments were characterized through DSC (Differential Scanning Calorimetry), XRD (X-ray Diffraction), Raman Spectroscopy, SEM (Scanning Electron Microscope), and mechanical tests. Phenomenal improvement in properties was found; modulus, strength, fracture strain, and elastic energy increased by 219%, 100%, 107% and 88%, respectively before strain hardening. Once strain hardened the strength, modulus and elastic energy increased by almost one order of magnitude. Source of these improvements were traced to increase in crystallinity and rate of crystallization, formation of microdroplets as a minor phase, sliding between minor and major phases, coating of nanotubes with polymer and alignment of nanotubes. / by Mujibur Rahman Khan. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

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