Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"VTI"”.
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Joint migration velocity analysis of PP- and PS-waves for VTI media
… velocity analysis can help build more accurate VTI velocity models. To avoid problems caused by the moveout asymmetry of PS-waves and take advantage of efficient MVA algorithms designed for pure modes, I suggest to generate pure SS-reflections from PP and PS data using the PP+PS=SS method. Then …
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Modeling, imaging and waveform-inversion in attenuative anisotropic media
… isotropic media with a vertical symmetry axis (VTI). The attenuation model is assumed to have the same symmetry as the velocity function and is described by the Thomsen-style attenuation parameters. First, the thesis introduces a time-domain finite-difference modeling technique for viscoelastic …
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Full-waveform inversion of time-lapse seismic data using physics-based and data-driven techniques
… transversely isotropic media with a vertical (VTI) and tilted (TTI) symmetry axis. In addition, I employ a ``source-independent" technique to mitigate the influence of errors in the source wavelet on the results of time-lapse FWI. Furthermore, the thesis presents machine-learning techniques …
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Cardiac hypertrophy and the dynamic changes in structure and function after pressure overload
… as did pulmonary velocity time integral (VTI), however aortic VTI remained constant. Discussion: From the analysis of the results it appears that KO mice were better protected against the development of pathological hypertrophy following pressure overload. This suggests strongly the …
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An Analysis of Focal Parameters with Application to West Texas Micro-Earthquakes
… m (244 m), and 258 m (265 m) for 5%, 10% and 15% VTI (HTI) cases, respectively. These results suggest that ignoring 5% seismic anisotropy can cause significant biases in microseismic event locations and anisotropy should be included in the velocity model to improve the location accuracy. …
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Mathematical Analysis of Upscaling Well Log Data from Sonic to Seismic Resolution
… respect to a Vertically Transversely Isotropic (VTI) media, which best corresponds to shales. It starts with the Simple Averaging upscaling method, which is a direct application of upscaling using the arithmetic mean. It then introduces a simple harmonic, simple geometric, and simple quadratic …
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Geomechanics and elastic anisotropy of the Bakken Formation, Williston Basin
… of anisotropy: vertically transverse isotropy (VTI), like shale, and horizontally transverse isotropy (HTI), like vertically fractured medium. These models have been used to describe how physical properties of rock vary in a medium. Identifying the anisotropy in a formation is important in …
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Seismic characterization of fractured reservoirs (part I) ; Crustal deformation in the Tibetan Plateau (part II)
… to anisotropic parameters of the equivalent VTI model and affect the NMO velocities. Studies show that the shear wave splitting parameter is most sensitive to crack density and is insensitive to saturating fluid content and the crack aspect ratio, while 8(v) and Ev) have different …
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A measurement system for and the measurement system of single particle energies in quantum dots
… use of a pumped 4He variable temperature insert (VTI), for which 1.2K represented the lowest working temperature. Although a 3He/4He dilution unit had been available for some time, the unit had exhibited an effective electron temperature of Te>7K. As a direct result of the work contained within …
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Anisotropic analysis of unconventional reservoirs using rock physics model: Eagle Ford shale case study
… stiffness tensor of the Eagle Ford shale in VTI media, I estimate the Thomsen parameters (i.e. anisotropy parameters). Anisotropy parameters epsilon, gamma and delta, on average, are 0.19, 0.29 and 0.04, respectively based on my modeling results in Eagle Ford shale. Anisotropic modeling …
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Eliciting farmer preferences for rice varietal trait improvements using an experimental methodology based on investment games
… for rice varietal trait improvements (VTIs). A total of 122 rice-farming households participated in the experiment, with both the husband and wife taking part in activities. The thesis consists of three core chapters, which specifically analyse the following: (i) farmers’ investment …
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Efficient modeling and waveform inversion of multicomponent seismic data for anisotropic media
… estimating the parameters of coupled fluid/solid VTI (transversely isotropic with a vertical symmetry axis) media using multicomponent ocean-bottom data. First, I develop a graphics processing unit (GPU)-based MFD+FSG algorithm to efficiently model elastic wavefields in anisotropic media. The CUDA …
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The Mechanism of Action of Hyaluronan Therapy as a Treatment for Osteoarthritis and the Assessment of Osteoarthritic Articular Cartilage Using Ultrasound
… experiments assessed shear-wave elastography (VTIQ/ARFI) for estimating cartilage elastic modulus and used hydrogel phantoms with known mechanical properties to determine the measurable range and limitations of elastographic stiffness estimation. Radiofrequency (RF) time-varying strain imaging …