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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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Showing 61 to 70 of 7479 (0.098 seconds)Spelling suggestions: "subject:"estimation"" "subject:"esstimation""
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Parameter Estimation in Magnetic Resonance ImagingGraff, Christian George January 2009 (has links)
This work concerns practical quantitative magnetic resonance (MR) imaging techniques and their implementation and use in clinical MR systems. First, background information on MR imaging is given, including the physics of the magnetic resonance, relaxation effects and how imaging is accomplished.Subsequently, the first part of this work describes the estimation of the T2 relaxation parameter from fast spin-echo (FSE) data. Various complications are considered, including partial volume and data from multiple receiver coils along with the effects of the timing parameters on the accuracy of T2 estimates. Next, the problem of classifying small (1 cm diameter) liver lesions using T2 estimates obtained from radially-acquired FSE data collected in a single breath-hold is considered. Several algorithms are proposed for obtaining lesion T2 estimates, and these algorithms are evaluated with a task-based metric, their ability to separate two classes of lesions, benign and malignant. A novel computer-generated phantom is developed for the generation of the data used in this evaluation.The second part of this work describes techniques that perform the separation of water and lipid signals while simultaneously estimating relaxation parameters that have clinical relevance. The acquisition sequences used here are Cartesian and radial versions of Gradient and Spin-Echo (GRASE). The radial GRASE technique is post-processed with a novel algorithm that estimates the T2 of the water signal independent of the lipid signal. The accuracy of this algorithm is evaluated in phantom and its potential use for detecting inflammation of the liver is evaluated using clinical data. Cartesian GRASE data is processed to obtain T2-dagger and lipid fraction estimates in bone which can be used to assess bone quality. The algorithm is tested in phantom and in vivo, and preliminary results are given.In the concluding chapter results are summarized and directions for future work are indicated.
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| 62 |
Using the piecewise exponential distribution to model the length of stay in a manpower planning systemGillan, Catherine C. January 1997 (has links)
No description available.
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| 63 |
On the estimation of the mixing density function in the mixture of exponentialsKhalil, M. A. M. January 1988 (has links)
No description available.
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| 64 |
Antenna diversity-assisted adaptive wireless multiuser OFDM systemsMünster, Matthias January 2002 (has links)
No description available.
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| 65 |
Estimation of exponentially damped sinusoidsPrior-Wandesforde, A. R. January 1988 (has links)
No description available.
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| 66 |
Bounds on quantities of physical interestWakefield, M. A. January 2003 (has links)
No description available.
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| 67 |
Accuracy driven adaptive nonlinear analysis of planar framed structuresChew, Alvin January 2001 (has links)
No description available.
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| 68 |
Developments in decomposition methods for power system state estimationAzzam, M. E. H. January 1985 (has links)
No description available.
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| 69 |
Colour content based image retrieval using spatial and perceptual cuesSeaborn, Matthew January 2001 (has links)
No description available.
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| 70 |
Some aspects of the auditory processing of sinusoidally rippled spectra in humansMcGuire, Stephanie N. January 2002 (has links)
No description available.
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