subject:(Inhomogeneity)

Universiteit Utrecht

1. Dam, A.N. van. Energy use and climate inhomogeneity in greenhouses.

Degree: 2014, Universiteit Utrecht

URL: http://dspace.library.uu.nl:8080/handle/1874/301317

► In the horticultural sector in the Netherlands a large amount of natural gas is used to optimize the climate inside the greenhouses. The idea is… (more)

Subjects/Keywords: Energy; greenhouses; climate; inhomogeneity

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APA (6^th Edition):

Dam, A. N. v. (2014). Energy use and climate inhomogeneity in greenhouses. (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/301317

Chicago Manual of Style (16^th Edition):

Dam, A N van. “Energy use and climate inhomogeneity in greenhouses.” 2014. Masters Thesis, Universiteit Utrecht. Accessed March 06, 2021. http://dspace.library.uu.nl:8080/handle/1874/301317.

MLA Handbook (7^th Edition):

Dam, A N van. “Energy use and climate inhomogeneity in greenhouses.” 2014. Web. 06 Mar 2021.

Vancouver:

Dam ANv. Energy use and climate inhomogeneity in greenhouses. [Internet] [Masters thesis]. Universiteit Utrecht; 2014. [cited 2021 Mar 06]. Available from: http://dspace.library.uu.nl:8080/handle/1874/301317.

Council of Science Editors:

Dam ANv. Energy use and climate inhomogeneity in greenhouses. [Masters Thesis]. Universiteit Utrecht; 2014. Available from: http://dspace.library.uu.nl:8080/handle/1874/301317

Louisiana State University

2. Bedayat, Houman. Poroelastic Inhomogeneities: Applications in Reservoir Geomechanics.

Degree: PhD, Petroleum Engineering, 2014, Louisiana State University

URL: etd-08192014-100028 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1803

► The scarce amount of conventional hydrocarbon reservoirs and increase of fuel consumption in the world have made production from unconventional hydrocarbon resources inevitable. Because… (more)

▼ The scarce amount of conventional hydrocarbon reservoirs and increase of fuel consumption in the world have made production from unconventional hydrocarbon resources inevitable. Because of the low permeability of unconventional formations, fractures are the main paths for the fluid to flow. Therefore, detailed knowledge of the size, orientation, and permeability of the fracture systems are essential for reservoir engineers. Permeability of the fractures is function of their volume and opening, and stress and fluid pore pressure distribution in the formation. Since reservoir pressure may change over the production life of the reservoir, studying stress redistribution and mechanical behavior of the reservoirs due to the fluid pressure alteration plays a critical role in successfully operating the hydrocarbon fields. This research investigates the behavior of poroelastic inclusions or inhomogeneities due to the pore pressure change, with applications in reservoir geomechanics. Considering different material properties and different pressure/temperature of hydrocarbon bearing formations in comparison to those of the surrounding geological structures, hydrocarbon reservoirs and subsurface fractures can be considered as inhomogeneities embedded inside an infinite poroelastic medium. Moreover, elliptic fractures are special cases of ellipsoidal inhomogeneities when their elastic moduli are zero, and one of the principal axes of the ellipsoid approaches zero. This dissertation is concerned with these two topics: the thorough study of poroelastic inclusions and their applications in reservoir geomechanics; and poroelastic fractures and their implications on the performance of hydrocarbon reservoirs. Analytical solutions for applied stress and strain distribution around single and double inhomogeneous poroelastic inclusions due to pore pressure changes in inclusions are derived, using Eshelby Equivalent Method (EIM) and assuming no hydraulic communication between the inclusion and the surrounding medium. This assumption is reasonable for modeling situations with large discrepancy between the permeability of the inclusion and the matrix. Later, considering hydraulic communication between the inclusion and the matrix, solution for the volume change of ellipsoidal poroelastic inclusions are derived.

Subjects/Keywords: Poroelasticity; Inclusion; Inhomogeneity; Eshelby; Geomechanics

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APA (6^th Edition):

Bedayat, H. (2014). Poroelastic Inhomogeneities: Applications in Reservoir Geomechanics. (Doctoral Dissertation). Louisiana State University. Retrieved from etd-08192014-100028 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1803

Chicago Manual of Style (16^th Edition):

Bedayat, Houman. “Poroelastic Inhomogeneities: Applications in Reservoir Geomechanics.” 2014. Doctoral Dissertation, Louisiana State University. Accessed March 06, 2021. etd-08192014-100028 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1803.

MLA Handbook (7^th Edition):

Bedayat, Houman. “Poroelastic Inhomogeneities: Applications in Reservoir Geomechanics.” 2014. Web. 06 Mar 2021.

Vancouver:

Bedayat H. Poroelastic Inhomogeneities: Applications in Reservoir Geomechanics. [Internet] [Doctoral dissertation]. Louisiana State University; 2014. [cited 2021 Mar 06]. Available from: etd-08192014-100028 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1803.

Council of Science Editors:

Bedayat H. Poroelastic Inhomogeneities: Applications in Reservoir Geomechanics. [Doctoral Dissertation]. Louisiana State University; 2014. Available from: etd-08192014-100028 ; https://digitalcommons.lsu.edu/gradschool_dissertations/1803

KTH

3. Nylund, Andreas. Off-resonance correction for magnetic resonance imaging with spiral trajectories.

Degree: Medical Engineering, 2014, KTH

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147925

► The procedure of cardiographic magnetic resonance imaging requires patients to hold their breath for up to twenty seconds, creating an uncomfortable situation for many… (more)

Subjects/Keywords: MRI; blur; spiral; inhomogeneity; off-resonance correction.

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APA (6^th Edition):

Nylund, A. (2014). Off-resonance correction for magnetic resonance imaging with spiral trajectories. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147925

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Nylund, Andreas. “Off-resonance correction for magnetic resonance imaging with spiral trajectories.” 2014. Thesis, KTH. Accessed March 06, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147925.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Nylund, Andreas. “Off-resonance correction for magnetic resonance imaging with spiral trajectories.” 2014. Web. 06 Mar 2021.

Vancouver:

Nylund A. Off-resonance correction for magnetic resonance imaging with spiral trajectories. [Internet] [Thesis]. KTH; 2014. [cited 2021 Mar 06]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147925.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Nylund A. Off-resonance correction for magnetic resonance imaging with spiral trajectories. [Thesis]. KTH; 2014. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147925

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Minnesota

4. Styczynski Snyder, Angela Lynn. Challenges of field inhomogeneities and a method for compensation.

Degree: PhD, Biomedical Engineering, 2011, University of Minnesota

URL: http://hdl.handle.net/11299/162262

► MRI of the body at 7 T has become possible only very recently. High fields bring the advantages of increased signal to noise ratio, resolution… (more)

Subjects/Keywords: 7T; B1 inhomogeneity; Liver; MRI; Spatiotemporal; Uterus

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APA (6^th Edition):

Styczynski Snyder, A. L. (2011). Challenges of field inhomogeneities and a method for compensation. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/162262

Chicago Manual of Style (16^th Edition):

Styczynski Snyder, Angela Lynn. “Challenges of field inhomogeneities and a method for compensation.” 2011. Doctoral Dissertation, University of Minnesota. Accessed March 06, 2021. http://hdl.handle.net/11299/162262.

MLA Handbook (7^th Edition):

Styczynski Snyder, Angela Lynn. “Challenges of field inhomogeneities and a method for compensation.” 2011. Web. 06 Mar 2021.

Vancouver:

Styczynski Snyder AL. Challenges of field inhomogeneities and a method for compensation. [Internet] [Doctoral dissertation]. University of Minnesota; 2011. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/11299/162262.

Council of Science Editors:

Styczynski Snyder AL. Challenges of field inhomogeneities and a method for compensation. [Doctoral Dissertation]. University of Minnesota; 2011. Available from: http://hdl.handle.net/11299/162262

University of Canterbury

5. Smale, Peter Rich. Observations and inhomogeneity in cosmology.

Degree: PhD, Astronomy, 2012, University of Canterbury

URL: http://dx.doi.org/10.26021/5947

► We interpret distance measurements from nearby galaxies, type Ia supernovae, and gamma-ray bursts in the light of a cosmological model that incorporates a spatial averaging… (more)

Subjects/Keywords: cosmology; timescape model; observational cosmology; inhomogeneity

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APA (6^th Edition):

Smale, P. R. (2012). Observations and inhomogeneity in cosmology. (Doctoral Dissertation). University of Canterbury. Retrieved from http://dx.doi.org/10.26021/5947

Chicago Manual of Style (16^th Edition):

Smale, Peter Rich. “Observations and inhomogeneity in cosmology.” 2012. Doctoral Dissertation, University of Canterbury. Accessed March 06, 2021. http://dx.doi.org/10.26021/5947.

MLA Handbook (7^th Edition):

Smale, Peter Rich. “Observations and inhomogeneity in cosmology.” 2012. Web. 06 Mar 2021.

Vancouver:

Smale PR. Observations and inhomogeneity in cosmology. [Internet] [Doctoral dissertation]. University of Canterbury; 2012. [cited 2021 Mar 06]. Available from: http://dx.doi.org/10.26021/5947.

Council of Science Editors:

Smale PR. Observations and inhomogeneity in cosmology. [Doctoral Dissertation]. University of Canterbury; 2012. Available from: http://dx.doi.org/10.26021/5947

National University of Ireland – Galway

6. Li, Ming. Macro- and micro-scale modelling of material inhomogeneity for the premature failure of welded 9Cr steels in power plants .

Degree: 2019, National University of Ireland – Galway

URL: http://hdl.handle.net/10379/14960

► Chromium-molybdenum steel pipe (9Cr-1Mo steel) is an important high temperature construction material for welded steam piping networks in gas-fired power plants. A major global problem… (more)

▼ Chromium-molybdenum steel pipe (9Cr-1Mo steel) is an important high temperature construction material for welded steam piping networks in gas-fired power plants. A major global problem of such materials is the premature failure which commonly occurs in the weld regions at elevated temperature. The primary objective of this thesis is the development of a macro- and micro-mechanical framework to predict this premature failure in the 9Cr-1Mo weldments. At the macro-scale level, a computational methodology for cyclic plasticity in multi-material welded components including laboratory scale test specimens and real plant is developed. At the micro-scale level, mixed-phase crystal plasticity models are developed to evaluate the mechanical performance of welding-induced micro-structure textures providing guidance into optimised heat treatments for welded components and material design for welded 9Cr-1Mo steel. For the work at the macro-scale level, a cyclic plasticity model including non-linear kinematic and isotropic hardening was adopted for the finite element analysis of welded 9Cr-1Mo steel in both cross-weld uniaxial test specimens and a welded T-piece power plant connection. The identified parameters are successfully calibrated and validated against uniaxial high temperature low cycle fatigue data from test data and the finite-element modelling of the cross-weld configuration, including three different material zones: parent metal, weld metal and heat-affected zone (HAZ). The predicted plastic strain in the cross-weld test is shown to concentrate in the HAZ at the interface region with parent metal, where the premature failure location is observed. The predicted critical location of the 9Cr-1Mo welded T-piece header-branch connection, as predicted by a three-dimensional finite element model under combined thermo-mechanical fatigue loading histories from Aghada power plant, is consistent with the location of observed premature cracking for in-service conditions. The results highlight the significant importance of incorporating multi-material cyclic plasticity parameters for prediction of plasticity and stress evolution in such welded connections. A key contribution of the present thesis is the development of a physically-based micro-mechanical framework for the modelling the ferrite-martensite inhomogeneity in the premature failure region of 9Cr-1Mo weldments. Previously-published monotonic tensile test data of IC-HAZ at 20 °C and 625 °C are adopted to calibrate the crystal plasticity finite element model of IC-HAZ. This demonstrated the importance of crystallographic orientation for localized stress and strain distributions, micro-crack initiation and subsequent damage evolution. Small volume fractions of ferrite are shown to have a clear detrimental effect on the mechanical behaviour of strength and ductility. The effect is significantly larger on both ductility and strength at 625 °C than at 20 °C. The micro-mechanical methodology demonstrates the key role of a small amount of ferrite on micro-crack nucleation and… Advisors/Committee Members: Leen, Sean (advisor).

Subjects/Keywords: 9Cr welds, HTLCF, crystal plasticity, material inhomogeneity; 9Cr welds; HTLCF; Crystal plasticity; Material inhomogeneity

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APA (6^th Edition):

Li, M. (2019). Macro- and micro-scale modelling of material inhomogeneity for the premature failure of welded 9Cr steels in power plants . (Thesis). National University of Ireland – Galway. Retrieved from http://hdl.handle.net/10379/14960

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Li, Ming. “Macro- and micro-scale modelling of material inhomogeneity for the premature failure of welded 9Cr steels in power plants .” 2019. Thesis, National University of Ireland – Galway. Accessed March 06, 2021. http://hdl.handle.net/10379/14960.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Li, Ming. “Macro- and micro-scale modelling of material inhomogeneity for the premature failure of welded 9Cr steels in power plants .” 2019. Web. 06 Mar 2021.

Vancouver:

Li M. Macro- and micro-scale modelling of material inhomogeneity for the premature failure of welded 9Cr steels in power plants . [Internet] [Thesis]. National University of Ireland – Galway; 2019. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/10379/14960.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Li M. Macro- and micro-scale modelling of material inhomogeneity for the premature failure of welded 9Cr steels in power plants . [Thesis]. National University of Ireland – Galway; 2019. Available from: http://hdl.handle.net/10379/14960

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

NSYSU

7. Wu, Shi-jia. Optimization of contrast and signal homogeneity for high resolution 3D MRI of human brain at 1.5 Tesla.

Degree: Master, Electrical Engineering, 2011, NSYSU

URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0903111-002141

► The inhomogeneous B1 field at higher main fields (B0) becomes more serious, leading to unsatisfactory MR image quality. To improve the signal homogeneity of routinely… (more)

Subjects/Keywords: centric phase encoding; CNR; MP2RAGE; B1 inhomogeneity; linear phase encoding; MPRAGE

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APA (6^th Edition):

Wu, S. (2011). Optimization of contrast and signal homogeneity for high resolution 3D MRI of human brain at 1.5 Tesla. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0903111-002141

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Wu, Shi-jia. “Optimization of contrast and signal homogeneity for high resolution 3D MRI of human brain at 1.5 Tesla.” 2011. Thesis, NSYSU. Accessed March 06, 2021. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0903111-002141.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Wu, Shi-jia. “Optimization of contrast and signal homogeneity for high resolution 3D MRI of human brain at 1.5 Tesla.” 2011. Web. 06 Mar 2021.

Vancouver:

Wu S. Optimization of contrast and signal homogeneity for high resolution 3D MRI of human brain at 1.5 Tesla. [Internet] [Thesis]. NSYSU; 2011. [cited 2021 Mar 06]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0903111-002141.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wu S. Optimization of contrast and signal homogeneity for high resolution 3D MRI of human brain at 1.5 Tesla. [Thesis]. NSYSU; 2011. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0903111-002141

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Rochester Institute of Technology

8. Pierce, W. Norman. The Effect of Negative and Positive Granularity on the Final Print Granularity.

Degree: School of Photographic Arts and Sciences (CIAS), 1966, Rochester Institute of Technology

URL: https://scholarworks.rit.edu/theses/6555

► Theoretically, the relation of negative and positive rms granularity to the final print granularity is described by the following equation: σ(D)print=[ σ(D)2negative material+ σ(D)2positive material]1/2.… (more)

Subjects/Keywords: Density; Emulsion; Granularity; Inhomogeneity; RMS

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APA (6^th Edition):

Pierce, W. N. (1966). The Effect of Negative and Positive Granularity on the Final Print Granularity. (Thesis). Rochester Institute of Technology. Retrieved from https://scholarworks.rit.edu/theses/6555

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Pierce, W Norman. “The Effect of Negative and Positive Granularity on the Final Print Granularity.” 1966. Thesis, Rochester Institute of Technology. Accessed March 06, 2021. https://scholarworks.rit.edu/theses/6555.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Pierce, W Norman. “The Effect of Negative and Positive Granularity on the Final Print Granularity.” 1966. Web. 06 Mar 2021.

Vancouver:

Pierce WN. The Effect of Negative and Positive Granularity on the Final Print Granularity. [Internet] [Thesis]. Rochester Institute of Technology; 1966. [cited 2021 Mar 06]. Available from: https://scholarworks.rit.edu/theses/6555.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Pierce WN. The Effect of Negative and Positive Granularity on the Final Print Granularity. [Thesis]. Rochester Institute of Technology; 1966. Available from: https://scholarworks.rit.edu/theses/6555

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Texas A&M University

9. Liu, Chao. Numerical Investigation of Light Scattering by Atmospheric Particles.

Degree: PhD, Atmospheric Sciences, 2013, Texas A&M University

URL: http://hdl.handle.net/1969.1/151138

► Atmospheric particles, i.e. ice crystals, dust particles, and black carbon, show significant complexities like irregular geometries, inhomogeneity, small-scale surface structures, and play a significant role… (more)

▼ Atmospheric particles, i.e. ice crystals, dust particles, and black carbon, show significant complexities like irregular geometries, inhomogeneity, small-scale surface structures, and play a significant role in the atmosphere by scattering and absorbing the incident solar radiation and terrestrial thermal emission. Knowledge of aerosol scattering properties is a fundamental but challenging aspect of radiative transfer studies and remote sensing applications. This dissertation tries to improve our understanding on the scattering properties of atmospheric particles by investigating both the scattering algorithms and the representation of the realistic particles. One part of this dissertation discusses in details the pseudo-spectral time domain algorithm (PSTD) for calculating scattering properties, its advantages and the elimination of the Gibbs phenomenon. The applicability of the parallelized PSTD implementation is investigated for both spherical and nonspherical particles over a wide range of sizes and refractive indices, and the PSTD is applied for spherical particles with size parameters up to 200, and randomly oriented non-spherical ones with size parameters up to 100. The relative strengths of the PSTD are also shown by a systematic comparison with the discrete dipole approximation (DDA). The PSTD outperforms the DDA for particles with refractive indices larger than 1.4, and ones with smaller refractive indices by large sizes (e.g. size parameters larger than 60 for a refractive index of 1.2). The results suggest significant potential of the PSTD for the numerical investigation of the light scattering and corresponding atmospheric applications. The other part of this dissertation investigates the effects of particle complexities on the light scattering properties of the atmospheric particles, and three aspects corresponding to the irregular geometry, inhomogeneity and surface roughness are studied. To cover the entire particle size range from the Rayleigh to the geometric- optics regimes, the PSTD (for relatively small particles) is combined with the im- proved geometric-optics method (IGOM) that is only applicable for large particles. The Koch-fractal geometry is introduced to model the light scattering properties of aerosol, and performs an excellent job of reproducing the experimental measurements of various mineral dust particles. For the inhomogeneous particles, the applicability of the effective medium approximations (EMA) is tested, and the EMA can be used to approximate the scattering properties of inhomogeneous particles only when the particles are uniformly internal mixtures. Furthermore, an irregular rough model is developed to study the effects of the small-scale surface roughness on the light scattering properties. In conclusion, the dissertation finds that the complexities of atmospheric particles have to be fully considered to obtain their scattering properties accurately. Advisors/Committee Members: Panetta, Richard Lee (advisor), Yang, Ping (advisor), Brooks, Sarah D. (committee member), Guermond, Jean-Luc (committee member).

Subjects/Keywords: Light Scattering; PSTD; Fractal Particles; Inhomogeneity; Surface Roughness

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APA (6^th Edition):

Liu, C. (2013). Numerical Investigation of Light Scattering by Atmospheric Particles. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151138

Chicago Manual of Style (16^th Edition):

Liu, Chao. “Numerical Investigation of Light Scattering by Atmospheric Particles.” 2013. Doctoral Dissertation, Texas A&M University. Accessed March 06, 2021. http://hdl.handle.net/1969.1/151138.

MLA Handbook (7^th Edition):

Liu, Chao. “Numerical Investigation of Light Scattering by Atmospheric Particles.” 2013. Web. 06 Mar 2021.

Vancouver:

Liu C. Numerical Investigation of Light Scattering by Atmospheric Particles. [Internet] [Doctoral dissertation]. Texas A&M University; 2013. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/1969.1/151138.

Council of Science Editors:

Liu C. Numerical Investigation of Light Scattering by Atmospheric Particles. [Doctoral Dissertation]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151138

Penn State University

10. Mushrif, Shreyas. INTUITIONISTIC FUZZY ROUGH SET BASED ALGORITHMS FOR MEDICAL IMAGE SEGMENTATION.

Degree: 2017, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/13832sxm5784

► Accurate segmentation of the magnetic resonance (MR) kidney images is very helpful for physiological study of kidney and the study of various kidney diseases. Segmentation… (more)

▼ Accurate segmentation of the magnetic resonance (MR) kidney images is very helpful for physiological study of kidney and the study of various kidney diseases. Segmentation of kidney images, especially into three primary tissue types- medulla, cortex, and pelvis is useful in computer-aided kidney surgery and disease diagnosis. Similarly, the study of disorders in brain is aided by accurate segmentation of the tissues in magnetic resonance (MR) brain images. The three main tissues in the brain- cerebrospinal fluid (CSF), gray matter (GM), and white matter (WM) must be segmented as accurately as possible in order to assist in neuroscience and neuro-medicine studies. However, due to unknown noise, intensity inhomogeneity, heterogeneity among the tissues (prevalent in kidney MR images), and weak boundaries, segmentation of kidney and brain MR images is quite a challenge. Therefore, this thesis presents segmentation algorithms that use image processing, pattern recognition, and soft computing techniques for identifying different tissues in kidney and brain MR images. This thesis integrates intuitionistic fuzzy sets, rough sets, and the concept of histon for the segmentation of kidney MR images. To reduce the uncertainty and vagueness in the kidney data, a novel membership function is proposed. This membership function is used to construct intuitionistic fuzzy representation for kidney MR images, which is in turn used to compute intuitionistic fuzzy roughness index. The intuitionistic fuzzy roughness index determines the significant peak and valley points, which provide accurate thresholds to segment the kidney MR image into medulla, cortex, and pelvis. The membership function proposed in this thesis is also used to construct an intuitionistic fuzzy representation for the brain images. For the brain images too, intuitionistic fuzzy roughness index determines the significant peak and valley points. Using these valley points, brain MR images are segmented into three classes- cerebrospinal fluid (CSF), grey matter (GM), and white matter (WM). But prior to segmentation, extra-cranial tissues such as skull, meninges, and blood vessels are discarded using a skull-stripping algorithm. The algorithms proposed for the segmentation of kidney and brain MR images are compared with the existing algorithms in their respective areas on the basis of quantitative indices such as under segmentation (UnS), over segmentation (OvS), incorrect segmentation (InS), Jaccard Similarity (JS), and Dice Coefficient (DC), which indicates better performance of the proposed algorithms for kidney and brain image segmentation. Advisors/Committee Members: Aldo Morales, Thesis Advisor/Co-Advisor, Susan Eskin, Committee Member, Christopher Sica, Committee Member.

Subjects/Keywords: Intuitionistic Fuzzy Set; Rough Sets; Intensity Inhomogeneity; Restricted Equivalence Functions; Histon

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APA (6^th Edition):

Mushrif, S. (2017). INTUITIONISTIC FUZZY ROUGH SET BASED ALGORITHMS FOR MEDICAL IMAGE SEGMENTATION. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/13832sxm5784

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mushrif, Shreyas. “INTUITIONISTIC FUZZY ROUGH SET BASED ALGORITHMS FOR MEDICAL IMAGE SEGMENTATION.” 2017. Thesis, Penn State University. Accessed March 06, 2021. https://submit-etda.libraries.psu.edu/catalog/13832sxm5784.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mushrif, Shreyas. “INTUITIONISTIC FUZZY ROUGH SET BASED ALGORITHMS FOR MEDICAL IMAGE SEGMENTATION.” 2017. Web. 06 Mar 2021.

Vancouver:

Mushrif S. INTUITIONISTIC FUZZY ROUGH SET BASED ALGORITHMS FOR MEDICAL IMAGE SEGMENTATION. [Internet] [Thesis]. Penn State University; 2017. [cited 2021 Mar 06]. Available from: https://submit-etda.libraries.psu.edu/catalog/13832sxm5784.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mushrif S. INTUITIONISTIC FUZZY ROUGH SET BASED ALGORITHMS FOR MEDICAL IMAGE SEGMENTATION. [Thesis]. Penn State University; 2017. Available from: https://submit-etda.libraries.psu.edu/catalog/13832sxm5784

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Luleå University of Technology

11. Anyairo, Charles Chukwudike. Cloud Inhomogeneity Effects in Microwave and Sub-mm Passive Sounder Data.

Degree: 2014, Luleå University of Technology

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-53776

Validerat; 20141114 (global_studentproject_submitter)

Subjects/Keywords: Technology; Cloud Inhomogeneity; Teknik

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APA (6^th Edition):

Anyairo, C. C. (2014). Cloud Inhomogeneity Effects in Microwave and Sub-mm Passive Sounder Data. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-53776

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Anyairo, Charles Chukwudike. “Cloud Inhomogeneity Effects in Microwave and Sub-mm Passive Sounder Data.” 2014. Thesis, Luleå University of Technology. Accessed March 06, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-53776.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Anyairo, Charles Chukwudike. “Cloud Inhomogeneity Effects in Microwave and Sub-mm Passive Sounder Data.” 2014. Web. 06 Mar 2021.

Vancouver:

Anyairo CC. Cloud Inhomogeneity Effects in Microwave and Sub-mm Passive Sounder Data. [Internet] [Thesis]. Luleå University of Technology; 2014. [cited 2021 Mar 06]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-53776.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Anyairo CC. Cloud Inhomogeneity Effects in Microwave and Sub-mm Passive Sounder Data. [Thesis]. Luleå University of Technology; 2014. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-53776

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign

12. LaBelle, Genevieve Marie. Distortion correction in magnetic resonance imaging using the simulated point spread function.

Degree: MS, Electrical & Computer Engr, 2016, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/90809

► Geometric distortion is a highly prevalent issue for echo-planar imaging (EPI), due to long readout times and field inhomogeneity. Previously, the measured point spread function… (more)

Subjects/Keywords: magnetic resonance imaging; point spread function; distortion; distortion correction; field inhomogeneity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

LaBelle, G. M. (2016). Distortion correction in magnetic resonance imaging using the simulated point spread function. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/90809

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

LaBelle, Genevieve Marie. “Distortion correction in magnetic resonance imaging using the simulated point spread function.” 2016. Thesis, University of Illinois – Urbana-Champaign. Accessed March 06, 2021. http://hdl.handle.net/2142/90809.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

LaBelle, Genevieve Marie. “Distortion correction in magnetic resonance imaging using the simulated point spread function.” 2016. Web. 06 Mar 2021.

Vancouver:

LaBelle GM. Distortion correction in magnetic resonance imaging using the simulated point spread function. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2016. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2142/90809.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

LaBelle GM. Distortion correction in magnetic resonance imaging using the simulated point spread function. [Thesis]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/90809

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Minnesota

13. Weinburd, Jasper. Patterns Selected by Spatial Inhomogeneity.

Degree: PhD, Mathematics, 2019, University of Minnesota

URL: http://hdl.handle.net/11299/206317

► This thesis studies patterns that form in environments with sharp spatial variation. In a uniform environment, spots or stripes typically form with a self-consistent width.… (more)

Subjects/Keywords: Dynamical Systems; Inhomogeneity; Normal Form; Pattern Formation; Swift-Hohenberg

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APA (6^th Edition):

Weinburd, J. (2019). Patterns Selected by Spatial Inhomogeneity. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/206317

Chicago Manual of Style (16^th Edition):

Weinburd, Jasper. “Patterns Selected by Spatial Inhomogeneity.” 2019. Doctoral Dissertation, University of Minnesota. Accessed March 06, 2021. http://hdl.handle.net/11299/206317.

MLA Handbook (7^th Edition):

Weinburd, Jasper. “Patterns Selected by Spatial Inhomogeneity.” 2019. Web. 06 Mar 2021.

Vancouver:

Weinburd J. Patterns Selected by Spatial Inhomogeneity. [Internet] [Doctoral dissertation]. University of Minnesota; 2019. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/11299/206317.

Council of Science Editors:

Weinburd J. Patterns Selected by Spatial Inhomogeneity. [Doctoral Dissertation]. University of Minnesota; 2019. Available from: http://hdl.handle.net/11299/206317

14. 上野, 育子. Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T : 7Ｔ頭部MRIにおける信号不均一の補正.

Degree: 医学博士, 2016, Iwate Medical University / 岩手医科大学

URL: http://id.nii.ac.jp/1181/00005685/

2015

Subjects/Keywords: 7T; MRI; intensity inhomogeneity correction; 7T; MRI; intensity inhomogeneity correction

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APA (6^th Edition):

上野, �. (2016). Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T : 7Ｔ頭部MRIにおける信号不均一の補正. (Thesis). Iwate Medical University / 岩手医科大学. Retrieved from http://id.nii.ac.jp/1181/00005685/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

上野, 育子. “Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T : 7Ｔ頭部MRIにおける信号不均一の補正.” 2016. Thesis, Iwate Medical University / 岩手医科大学. Accessed March 06, 2021. http://id.nii.ac.jp/1181/00005685/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

上野, 育子. “Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T : 7Ｔ頭部MRIにおける信号不均一の補正.” 2016. Web. 06 Mar 2021.

Vancouver:

上野 �. Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T : 7Ｔ頭部MRIにおける信号不均一の補正. [Internet] [Thesis]. Iwate Medical University / 岩手医科大学; 2016. [cited 2021 Mar 06]. Available from: http://id.nii.ac.jp/1181/00005685/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

上野 �. Intensity inhomogeneity correction for magnetic resonance imaging of human brain at 7T : 7Ｔ頭部MRIにおける信号不均一の補正. [Thesis]. Iwate Medical University / 岩手医科大学; 2016. Available from: http://id.nii.ac.jp/1181/00005685/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

15. Woo, Steffi Y. Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties.

Degree: PhD, 2017, McMaster University

URL: http://hdl.handle.net/11375/22107

►

Ternary InGaN and AlGaN alloys have been sought after for the application of various optoelectronic devices spanning a large spectral range between the deep ultraviolet… (more)

▼

Ternary InGaN and AlGaN alloys have been sought after for the application of various optoelectronic devices spanning a large spectral range between the deep ultraviolet and infrared, including light-emitting diodes, and laser diodes. Their non-ideal alloy mixing, and differences in bond energy and in adatom diffusion are established as the cause for various types of nanoscale compositional inhomogeneity commonly observed in nitride thin films. Growth in a nanowire geometry can overcome the phase separation, surface segregation, and chemical ordering by providing enhanced strain relaxation of the large lattice mismatch at the free surfaces. In this dissertation, the spectral and spatial luminescence distributions of ternary III-N alloy nanowire heterostructures are investigated and correlated to structural and chemical properties with scanning transmission electron microscopy. Quantitative elemental mapping of InGaN/GaN dot-in-a-wire structures using electron energy-loss spectroscopy revealed compositional non-uniformity between successive quantum dots. Local strain mapping of the heterostructure showed a dependence of the incorporation of indium on the magnitude of the out-of-plane compressive strain within the underlying GaN barrier layer. Cathodoluminescence spectroscopy on individual nanowires presented diverse emission properties, nevertheless, the In-content variability could be directly correlated to the broad range of peak emission energies. Atomic-level chemical ordering within the InGaN was then reported, and attributed to the faceted growth surface in nanowires that promotes preferential site incorporation by In-atoms that allows for better strain relaxation. Distinct atomic-scale alloy inhomogeneities were also investigated in AlGaN nanowires, which evidenced spatial localization of carriers taking place at the resulting energy band fluctuations. A high spectral density of narrow emission lines arose from such compositional modulations, whose luminescence behaviours exhibit a dependence on the nature of the compositional fluctuations from which they originate.

Thesis

Doctor of Philosophy (PhD)

Advisors/Committee Members: Botton, Gianluigi A., Materials Science and Engineering.

Subjects/Keywords: scanning transmission electron microscopy; semiconductor nanowires; III-nitride; heterostructures; alloy inhomogeneity; characterization; nanotechnology

10 more images…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Woo, S. Y. (2017). Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/22107

Chicago Manual of Style (16^th Edition):

Woo, Steffi Y. “Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties.” 2017. Doctoral Dissertation, McMaster University. Accessed March 06, 2021. http://hdl.handle.net/11375/22107.

MLA Handbook (7^th Edition):

Woo, Steffi Y. “Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties.” 2017. Web. 06 Mar 2021.

Vancouver:

Woo SY. Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties. [Internet] [Doctoral dissertation]. McMaster University; 2017. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/11375/22107.

Council of Science Editors:

Woo SY. Anomalous Structural Variations in III-Nitride Nanowire Heterostructures and Their Corresponding Optical Properties. [Doctoral Dissertation]. McMaster University; 2017. Available from: http://hdl.handle.net/11375/22107

University of Toronto

16. Brown, Meghan. Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease.

Degree: 2011, University of Toronto

URL: http://hdl.handle.net/1807/30524

►

Rationale: Ventilation inhomogeneity (VI) may be an early sign of obstructive airway disease. The lung clearance index (LCI) has been suggested as a sensitive marker… (more)

Subjects/Keywords: Ventilation Inhomogeneity; Lung Clearance Index; Cystic Fibrosis; Asthma; Childhood; Lung development; 0719

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APA (6^th Edition):

Brown, M. (2011). Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/30524

Chicago Manual of Style (16^th Edition):

Brown, Meghan. “Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease.” 2011. Masters Thesis, University of Toronto. Accessed March 06, 2021. http://hdl.handle.net/1807/30524.

MLA Handbook (7^th Edition):

Brown, Meghan. “Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease.” 2011. Web. 06 Mar 2021.

Vancouver:

Brown M. Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease. [Internet] [Masters thesis]. University of Toronto; 2011. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/1807/30524.

Council of Science Editors:

Brown M. Lung Clearance Index as a Marker of Ventilation Inhomogeneity in Early Childhood with Health and Disease. [Masters Thesis]. University of Toronto; 2011. Available from: http://hdl.handle.net/1807/30524

Universidade Nova

17. Moreno, Miriam Zarza. Monte Carlo simulations for dosimetric verification in photon and electron beam radiotherapy.

Degree: 2012, Universidade Nova

URL: http://www.rcaap.pt/detail.jsp?id=oai:run.unl.pt:10362/7835

►

Dissertação para obtenção do Grau de Doutor em Engenharia Biomédica

One of the primary requirements for successful radiotherapy treatments is the accurate calculation of dose… (more)

▼

Dissertação para obtenção do Grau de Doutor em Engenharia Biomédica

One of the primary requirements for successful radiotherapy treatments is the accurate calculation of dose distributions in the treatment planning process. Monte Carlo (MC) dose calculation algorithms are currently recognized as the most accurate method to meet this requirement and to increase even further dose accuracy. The improvements in computer processor technology and the development of variance reduction techniques for calculations have led to the recent implementation and use of MC algorithms for radiotherapy treatment planning at many clinical departments. The work conducting to the present thesis consists of several dosimetric studies which demonstrate the potential use of MC dose calculations as a robust tool of dose verification in two different fields of external radiotherapy: electron and photon beam radiotherapy. The first purpose of these studies is to evaluate dose distributions in challenging situations where conventional dose calculation algorithms have shown some limitations and it is very difficult to measure using typical clinical dosimetric procedures, namely in regions containing tissue inhomogeneities, such as air cavities and bones, and in superficial regions. A second goal of the present work is to use MC simulations to provide a detailed characterization of photon beams collimated by a multileaf collimator (MLC) in order to assess the dosimetric influences of these devices for the MC modeling of Intensity Modulated Radiotherapy (IMRT) plans. Detailed MC model of a Varian 2100 C/D linear accelerator and the Millenium MLC incorporated in the treatment head is accurately verified against measurements performed with ionization chambers and radiographic films. Finally, it is also an aim of this thesis to make a contribution for solving one of the current problems associated with the implementation and use of the MC method for radiotherapy treatment planning, namely the clinical impact of converting dose-to-medium to dose-to-water in treatment planning and dosimetric evaluation. For this purpose, prostate IMRT plans previously generated by a conventional dose algorithm are validated with the MC method using an alternative method, which involves the use of non-standard CT conversion ramps to create CT-based simulation phantoms.

Fundação para a Ciência e Tecnologia; Centro de Física Nuclear da Universidade de Lisboa

Advisors/Committee Members: Paula, Grisel, Jesus, Adelaide Pedro de.

Subjects/Keywords: Monte Carlo algorithms; Radiation dosimetry; Air inhomogeneity; Multileaf collimator; Superficial dose; Intensity modulated radiotherapy

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APA (6^th Edition):

Moreno, M. Z. (2012). Monte Carlo simulations for dosimetric verification in photon and electron beam radiotherapy. (Thesis). Universidade Nova. Retrieved from http://www.rcaap.pt/detail.jsp?id=oai:run.unl.pt:10362/7835

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Moreno, Miriam Zarza. “Monte Carlo simulations for dosimetric verification in photon and electron beam radiotherapy.” 2012. Thesis, Universidade Nova. Accessed March 06, 2021. http://www.rcaap.pt/detail.jsp?id=oai:run.unl.pt:10362/7835.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Moreno, Miriam Zarza. “Monte Carlo simulations for dosimetric verification in photon and electron beam radiotherapy.” 2012. Web. 06 Mar 2021.

Vancouver:

Moreno MZ. Monte Carlo simulations for dosimetric verification in photon and electron beam radiotherapy. [Internet] [Thesis]. Universidade Nova; 2012. [cited 2021 Mar 06]. Available from: http://www.rcaap.pt/detail.jsp?id=oai:run.unl.pt:10362/7835.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Moreno MZ. Monte Carlo simulations for dosimetric verification in photon and electron beam radiotherapy. [Thesis]. Universidade Nova; 2012. Available from: http://www.rcaap.pt/detail.jsp?id=oai:run.unl.pt:10362/7835

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Iowa

18. Balachandrasekaran, Arvind. Structured low rank approaches for exponential recovery - application to MRI.

Degree: PhD, Electrical and Computer Engineering, 2018, University of Iowa

URL: https://ir.uiowa.edu/etd/6543

► Recovering a linear combination of exponential signals characterized by parameters is highly significant in many MR imaging applications such as parameter mapping and spectroscopy.… (more)

▼ Recovering a linear combination of exponential signals characterized by parameters is highly significant in many MR imaging applications such as parameter mapping and spectroscopy. The parameters carry useful clinical information and can act as biomarkers for various cardiovascular and neurological disorders. However, their accurate estimation requires a large number of high spatial resolution images, resulting in long scan time. One of the ways to reduce scan time is by acquiring undersampled measurements. The recovery of images is usually posed as an optimization problem, which is regularized by functions enforcing sparsity, smoothness or low rank structure. Recently structured matrix priors have gained prominence in many MRI applications because of their superior performance over the aforementioned conventional priors. However, none of them are designed to exploit the smooth exponential structure of the 3D dataset. In this thesis, we exploit the exponential structure of the signal at every pixel location and the spatial smoothness of the parameters to derive a 3D annihilation relation in the Fourier domain. This relation translates into a product of a Hankel/Toeplitz structured matrix, formed from the k-t samples, and a vector of filter coefficients. We show that this matrix has a low rank structure, which is exploited to recover the images from undersampled measurements. We demonstrate the proposed method on the problem of MR parameter mapping. We compare the algorithm with the state-of-the-art methods and observe that the proposed reconstructions and parameter maps have fewer artifacts and errors. We extend the structured low rank framework to correct field inhomogeneity artifacts in MR images. We introduce novel approaches for field map compensation for data acquired using Cartesian and non-Cartesian trajectories. We adopt the time segmentation approach and reformulate the artifact correction problem into a recovery of time series of images from undersampled measurements. Upon recovery, the first image of the series will correspond to the distortion-free image. With the above re-formulation, we can assume that the signal at every pixel follows an exponential signal characterized by field map and the damping constant R2*. We exploit the smooth exponential structure of the 3D dataset to derive a low rank structured matrix prior, similar to the parameter mapping case. We demonstrate the algorithm on spherical MR phantom and human data and show that the artifacts are greatly reduced compared to the uncorrected images. Finally, we develop a structured matrix recovery framework to accelerate cardiac breath-held MRI. We model the cardiac image data as a 3D piecewise constant function. We assume that the zeros of a 3D trigonometric polynomial coincides with the edges of the image data, resulting in a Fourier domain annihilation relation. This relation can be compactly expressed in terms of a structured low rank matrix. We exploit this low rank property to recover the cardiac images from… Advisors/Committee Members: Jacob, Mathews (supervisor).

Subjects/Keywords: Dynamic MRI; Exponential recovery; Field inhomogeneity correction; Parameter mapping; Structured matrix; Electrical and Computer Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Balachandrasekaran, A. (2018). Structured low rank approaches for exponential recovery - application to MRI. (Doctoral Dissertation). University of Iowa. Retrieved from https://ir.uiowa.edu/etd/6543

Chicago Manual of Style (16^th Edition):

Balachandrasekaran, Arvind. “Structured low rank approaches for exponential recovery - application to MRI.” 2018. Doctoral Dissertation, University of Iowa. Accessed March 06, 2021. https://ir.uiowa.edu/etd/6543.

MLA Handbook (7^th Edition):

Balachandrasekaran, Arvind. “Structured low rank approaches for exponential recovery - application to MRI.” 2018. Web. 06 Mar 2021.

Vancouver:

Balachandrasekaran A. Structured low rank approaches for exponential recovery - application to MRI. [Internet] [Doctoral dissertation]. University of Iowa; 2018. [cited 2021 Mar 06]. Available from: https://ir.uiowa.edu/etd/6543.

Council of Science Editors:

Balachandrasekaran A. Structured low rank approaches for exponential recovery - application to MRI. [Doctoral Dissertation]. University of Iowa; 2018. Available from: https://ir.uiowa.edu/etd/6543

University of Illinois – Urbana-Champaign

19. Clifford, Bryan Alexander. Subspace estimation for subspace-based magnetic resonance spectroscopic imaging.

Degree: MS, Electrical & Computer Engr, 2016, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/90903

► Magnetic resonance spectroscopic imaging (MRSI) is a powerful technique that offers us the ability to non-invasively image chemical distributions within the human body. However, due… (more)

Subjects/Keywords: subspace model; subspace estimation; field inhomogeneity; magnetic resonance; MRI; MRSI; spectroscopy; spectroscopic imaging

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APA (6^th Edition):

Clifford, B. A. (2016). Subspace estimation for subspace-based magnetic resonance spectroscopic imaging. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/90903

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Clifford, Bryan Alexander. “Subspace estimation for subspace-based magnetic resonance spectroscopic imaging.” 2016. Thesis, University of Illinois – Urbana-Champaign. Accessed March 06, 2021. http://hdl.handle.net/2142/90903.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Clifford, Bryan Alexander. “Subspace estimation for subspace-based magnetic resonance spectroscopic imaging.” 2016. Web. 06 Mar 2021.

Vancouver:

Clifford BA. Subspace estimation for subspace-based magnetic resonance spectroscopic imaging. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2016. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2142/90903.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Clifford BA. Subspace estimation for subspace-based magnetic resonance spectroscopic imaging. [Thesis]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/90903

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Johannes Gutenberg Universität Mainz

20. Kalesse, Heike. Influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective radius.

Degree: 2009, Johannes Gutenberg Universität Mainz

URL: http://ubm.opus.hbz-nrw.de/volltexte/2010/2269/

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Diese Dissertation untersucht den Einfluss von Eiskristallform und räumlicher Inhomogenität von Zirren auf das Retrieval von optischer Wolkendicke und effektivem Eispartikelradius. Zu diesem Zweck werden… (more)

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Diese Dissertation untersucht den Einfluss von Eiskristallform und räumlicher Inhomogenität von Zirren auf das Retrieval von optischer Wolkendicke und effektivem Eispartikelradius. Zu diesem Zweck werden flugzeuggetragene spektrale Messungen solarer Strahlung sowie solare und langwellige Strahlungstransfersimulationen durchgeführt. Flugzeuggetragene spektrale aufwärtsgerichtete Radianzen (Strahldichten) sind mit dem SMART-Albedometer (Spectral Modular Airborne Radiation measurement sysTem) während des CIRCLE-2 (CIRrus CLoud Experiment-2) Feldexperiments im Mai 2007 gemessen worden. Basierend auf diesen Radianzdaten werden mittels eines Wolkenretrievalalgorithmus optische Wolkendicken und effektive Eispartikelradien anhand von eindimensionalen Strahlungstransferrechnungen bestimmt. Die Auswirkung der Annahme unterschiedlicher Eiskristallformen auf die retrievten Parameter wird durch Variation der Einfachstreueigenschaften der Eispartikel untersucht. Darüber hinaus wird mittels Strahlungstransferrechnungen auch der Einfluss der Eiskristallform auf den Strahlungsantrieb von Eiswolken ermittelt. Die Frage nach dem relativen Einfluss von räumlicher Wolkeninhomogenität und Eiskristallform wird anhand von dreidimensionalen und independent pixel approximation (IPA) Strahlungssimulationen untersucht. Die Analyse basiert auf einer Modelleiswolke, die aus Daten des NASA (National Aeronautics and Space Administration) TC4 (Tropical Composition, Cloud, and Climate Coupling) Feldexperiments im Sommer 2007 in Costa Rica erzeugt wurde. Lokal gesehen können beide Effekte - Eiskristallform und räumliche Eiswolkeninhomogenität - die gleiche Grössenordnung haben und zu einer Unter- bzw. Überschätzung der retrievten Parameter um 40 – 60% führen. Gemittelt über die ganze Wolke ist jedoch der Einfluss der Eiskristallform viel bedeutender als der von räumlichen Inhomogenitäten.

This PhD thesis investigates the influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective ice particle radius. For this purpose airborne spectral solar radiation measurements as well as solar and thermal infrared radiative transfer simulations are conducted. Airborne spectral upwelling radiance data are obtained with the Spectral Modular Airborne Radiation measurement sysTem (SMART-Albedometer) within the frame of the CIRrus CLoud Experiment-2 (CIRCLE-2) in May 2007. Based on these radiance data a cloud retrieval algorithm is employed to derive cirrus optical thickness and particle effective radius from one-dimensional (1D) radiative transfer calculations. The influence of ice particle shape on retrieved properties is evaluated by variation of the ice particle single-scattering properties in the retrieval. Also, the impact of ice particle habit on cirrus radiative forcing is studied by radiative transfer simulations. The question of relative importance of cirrus spatial heterogeneity and ice particle shape is addressed via three-dimensional (3D) and independent pixel approximation (IPA) cirrus…

Subjects/Keywords: Zirren, Strahlungsübertragungsrechnungen, optische Wolkendicke, effektiver Eispartikelradius, Wolkeninhomogenität; cirrus, radiative transfer calculations, optical thickness, effective radius, cloud inhomogeneity; Natural sciences and mathematics

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APA (6^th Edition):

Kalesse, H. (2009). Influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective radius. (Doctoral Dissertation). Johannes Gutenberg Universität Mainz. Retrieved from http://ubm.opus.hbz-nrw.de/volltexte/2010/2269/

Chicago Manual of Style (16^th Edition):

Kalesse, Heike. “Influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective radius.” 2009. Doctoral Dissertation, Johannes Gutenberg Universität Mainz. Accessed March 06, 2021. http://ubm.opus.hbz-nrw.de/volltexte/2010/2269/.

MLA Handbook (7^th Edition):

Kalesse, Heike. “Influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective radius.” 2009. Web. 06 Mar 2021.

Vancouver:

Kalesse H. Influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective radius. [Internet] [Doctoral dissertation]. Johannes Gutenberg Universität Mainz; 2009. [cited 2021 Mar 06]. Available from: http://ubm.opus.hbz-nrw.de/volltexte/2010/2269/.

Council of Science Editors:

Kalesse H. Influence of ice crystal habit and cirrus spatial inhomogeneities on the retrieval of cirrus optical thickness and effective radius. [Doctoral Dissertation]. Johannes Gutenberg Universität Mainz; 2009. Available from: http://ubm.opus.hbz-nrw.de/volltexte/2010/2269/

University of Alberta

21. Eissa, Amir. Investigation of gradient echo MRI for blood vessel imaging and susceptibility-weighted imaging in the human brain.

Degree: PhD, Department of Physics, 2010, University of Alberta

URL: https://era.library.ualberta.ca/files/h415p993w

► Despite the vast myriad of applications and the long way it has come, MRI is still a relatively new field of knowledge with much prospect… (more)

▼ Despite the vast myriad of applications and the long way it has come, MRI is still a relatively new field of knowledge with much prospect for more advancement and expansion. This work is mainly concerned with two gradient echo imaging methods which are directly or indirectly related to blood vessel imaging as well as iron depiction in the human brain. In each case, new methods are introduced that overcome existing limitations. For blood vessel imaging, 3D Time-of-Flight (TOF) MR angiography (MRA) with its known capability to image arteries as well as veins was implemented at 3.0 T. At this field strength, the significant RF profile variability due to RF inhomogeneity is a liability for circle-of-Willis imaging in the human brain that was overcome by introducing a new means to counter the RF effects through increased slope of the ramped pulse. In addition a new method is introduced for TOF MRA with two-in-one arterial and venous 3D TOF imaging to overcome the significant scan time overhead of a traditional second venous scan and for cutting down RF power utilization. Using this method, total scan time could be reduced by as much as 46% and specific absorption rate (SAR) due to spatial saturation could be reduced by as much as 92%. For iron sensitive imaging, Susceptibility Weighted Imaging (SWI) was developed at 4.7 T. The phase SWI method was used to visualize lesions in Multiple Sclerosis (MS) patients and was experimentally compared to the visibility on standard T2 weighting with results demonstrating visualization of new lesions, with 18% of total lesions exclusively visible on SWI. A new approach to 3D imaging was also introduced to enable accurate oblique SWI scanning while overcoming the current restriction to axial imaging to produce correct phase effects for oblique imaging. New results from oblique phase imaging were presented and the phase measurements from key brain structures were successfully validated against images obtained by the current standard of axial imaging.

Subjects/Keywords: Angiography; SAR; Phase; SWI; MRI; 3D imaging; Inhomogeneity; Intracranial; Multiple sclerosis; Venography; Iron; oblique; RF; High field

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Eissa, A. (2010). Investigation of gradient echo MRI for blood vessel imaging and susceptibility-weighted imaging in the human brain. (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/h415p993w

Chicago Manual of Style (16^th Edition):

Eissa, Amir. “Investigation of gradient echo MRI for blood vessel imaging and susceptibility-weighted imaging in the human brain.” 2010. Doctoral Dissertation, University of Alberta. Accessed March 06, 2021. https://era.library.ualberta.ca/files/h415p993w.

MLA Handbook (7^th Edition):

Eissa, Amir. “Investigation of gradient echo MRI for blood vessel imaging and susceptibility-weighted imaging in the human brain.” 2010. Web. 06 Mar 2021.

Vancouver:

Eissa A. Investigation of gradient echo MRI for blood vessel imaging and susceptibility-weighted imaging in the human brain. [Internet] [Doctoral dissertation]. University of Alberta; 2010. [cited 2021 Mar 06]. Available from: https://era.library.ualberta.ca/files/h415p993w.

Council of Science Editors:

Eissa A. Investigation of gradient echo MRI for blood vessel imaging and susceptibility-weighted imaging in the human brain. [Doctoral Dissertation]. University of Alberta; 2010. Available from: https://era.library.ualberta.ca/files/h415p993w

Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)

22. Stefanaki, Eleni-Chrysanthi. Μελέτη πολυφασικών θερμοηλεκτρικών υλικών.

Degree: 2018, Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)

URL: http://hdl.handle.net/10442/hedi/42824

►

In the present thesis, the microstructure of multiphase thermoelectric materials is studied along with their effect on their thermoelectric properties. The study is applied on… (more)

▼

In the present thesis, the microstructure of multiphase thermoelectric materials is studied along with their effect on their thermoelectric properties. The study is applied on lead chalcogenides PbTe, PbSe, the binary system Mg2Si and pseudo-ternary Mg2(Si,Sn,Ge). All the aforementioned compounds hold outstanding thermoelectric properties, while the synthesis technique is not the same. Another common characteristic among these four compounds is the complex band structure they possess: the valence band of chalcogenides constitutes of two subbands (L, Σ points inside Brillouin zone), while the conduction band of Mg2Si, Mg2Sn constitutes of two subbands (Χ3, Χ1). The complex band structure of the aforementioned compounds is studied, incorporating different models (parabolic, non parabolic). The density of states effective mass (m*D), susceptibility effective mass (m*S), longitudinal (m*L) and transverse components (m*T), the Hall mobility ratio of the two subbands L, U (b=μH,L/μH,U), the anisotropy ratio Κ=m*L/m*T and the Fermi energy level of the occupied conduction/valence band constitute the fundamental parameters that are calculated. In the literature, thermoelectric materials are studied macroscopically since they are regarded as homogeneous. From the present study derives the existence of in-homogeneities in chemical synthesis and thermoelectric properties. The study of micro-structure is applied across all length-scales: from atomic-scale using X-ray Diffraction (XRD), nano-scale using Transmission Electron Microscopy (TEM) and High Resolution TEM (HRTEM/EDS), micro-scale with Scanning Electron Microscopy with Electron Diffraction Spectroscopy (SEM/EDS) to meso-scale with Fourier Transform Infrared spectroscopy (FTIR), scanning-IR and scanning- Seebeck. Furthermore, electrical conductivity and Hall-effect measurements are applied. All results support the existence of in-homogeneities in all length-scales a) in the distribution of dopant concentration inside the solid solution and b) with hetero-structures created implying phase separation. Phase separation is attributed to the miscibility gap in the phase diagram of the two compounds, while the mechanism is nucleation and growth upon cooling. Furthermore the plasmon frequency ωp was studied as a potential effective probe for carrier inhomogeneity and consequently doping differentiation based on its dependence of the carrier concentration.

Στην παρούσα διατριβή πραγματοποιήθηκε μελέτη πολυφασικών θερμοηλεκτρικών υλικών καθώς και μελέτη της επίδρασης της μικροδομής στις θερμοηλεκτρικές τους ιδιότητες. Η έρευνα τα τελευταία χρόνια στον τομέα αυτό εντοπίζεται στην βελτιστοποίηση των ιδιοτήτων των θερμοηλεκτρικών υλικών για διατάξεις μεγαλύτερης απόδοσης. Τα πολυφασικά υλικά τα οποία μελετήθηκαν αποτελούν τη νέα γενιά υλικών και περιλαμβάνουν τα χαλκογενίδια του μολύβδου PbTe, PbSe, το δυαδικό σύστημα Mg2Si και το ψευδο-τριαδικό Mg2(Si,Sn,Ge). Η ανάπτυξη αυτών έχει πραγματοποιηθεί με διαφορετικές τεχνικές και διαθέτουν όλα άριστες θερμοηλεκτρικές ιδιότητες. Το…

Subjects/Keywords: Θερμοηλεκτρικά υλικά; Πυριτιούχο μαγνήσιο; Τελλουριούχος μόλυβδος; Σελινιούχος μόλυβδος; Ανομοιογένειες; Thermoelectric materials; Magnesium silicide; Lead telluride; Lead selenide; Inhomogeneity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Stefanaki, E. (2018). Μελέτη πολυφασικών θερμοηλεκτρικών υλικών. (Thesis). Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ). Retrieved from http://hdl.handle.net/10442/hedi/42824

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Stefanaki, Eleni-Chrysanthi. “Μελέτη πολυφασικών θερμοηλεκτρικών υλικών.” 2018. Thesis, Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ). Accessed March 06, 2021. http://hdl.handle.net/10442/hedi/42824.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Stefanaki, Eleni-Chrysanthi. “Μελέτη πολυφασικών θερμοηλεκτρικών υλικών.” 2018. Web. 06 Mar 2021.

Vancouver:

Stefanaki E. Μελέτη πολυφασικών θερμοηλεκτρικών υλικών. [Internet] [Thesis]. Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ); 2018. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/10442/hedi/42824.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Stefanaki E. Μελέτη πολυφασικών θερμοηλεκτρικών υλικών. [Thesis]. Aristotle University Of Thessaloniki (AUTH); Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ); 2018. Available from: http://hdl.handle.net/10442/hedi/42824

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Vanderbilt University

23. Moore, Jason Edward. Radio Frequency Pulse Designs for Magnetic Resonance at High Field.

Degree: PhD, Physics, 2011, Vanderbilt University

URL: http://hdl.handle.net/1803/11602

► The increased signal-to-noise ratio (SNR) that accompanies the use of stronger static fields in magnetic resonance imaging (MRI) has driven the use of increasingly higher… (more)

▼ The increased signal-to-noise ratio (SNR) that accompanies the use of stronger static fields in magnetic resonance imaging (MRI) has driven the use of increasingly higher fields ever since the technology's inception over thirty years ago. Currently, the potential clinical use of 7 Tesla (7 T) MRI scanners is under investigation. At such high fields, a number of complications prohibit practical realization of the potential gains in SNR and reduce image quality. One major problem is the inhomogeneity of radio frequency (RF) fields that originates when transmitted RF wavelengths are comparable to the dimensions of the human body. When this condition is fulfilled, significant RF attenuation and interference result, leading to spatially varying MR signal intensities. This thesis addresses the challenge of nonuniform RF fields through the design of RF pulses that induced magnetization responses largely independent of underlying RF field variations. The advantages of this approach are that pulse designs are not patient-specific and can even be implemented across a range of static field strengths. Drawbacks to such strategies involve the limited degree to which uniform magnetization responses can be achieved given the practical restrictions of RF pulse power and duration. Pulse designs rely upon numerical optimization of RF modulation patterns composed of series of discrete sub-pulses. Such composite pulses have been designed for excitation, inversion, refocusing, and saturation and largely tolerate the field variations observed in the human brain at 7 T. In all cases, appropriate comparisons are made with established field-insensitive pulse designs, and performance as a function of pulse power and duration is considered in detail. Results indicate that use of numerically optimized composite pulses can greatly reduce the effects of nonuniform RF fields in almost any pulse sequence employed in the human brain at 7 T. In addition to field-insensitive composite pulses, this thesis includes an evaluation of RF field mapping protocols, the numerical optimization of adiabatic pulses, and the design of frequency-selective composite pulses for a number of applications at both low and high field strengths. Advisors/Committee Members: Todd E. Peterson (committee member), Cynthia B. Paschal (committee member), Adam W. Anderson (committee member), Volker E. Oberacker (committee member), John C. Gore (Committee Chair).

Subjects/Keywords: RF field inhomogeneity; B1-insensitivity; NMR excitation and refocusing; high field MRI; composite radio frequency pulses

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Moore, J. E. (2011). Radio Frequency Pulse Designs for Magnetic Resonance at High Field. (Doctoral Dissertation). Vanderbilt University. Retrieved from http://hdl.handle.net/1803/11602

Chicago Manual of Style (16^th Edition):

Moore, Jason Edward. “Radio Frequency Pulse Designs for Magnetic Resonance at High Field.” 2011. Doctoral Dissertation, Vanderbilt University. Accessed March 06, 2021. http://hdl.handle.net/1803/11602.

MLA Handbook (7^th Edition):

Moore, Jason Edward. “Radio Frequency Pulse Designs for Magnetic Resonance at High Field.” 2011. Web. 06 Mar 2021.

Vancouver:

Moore JE. Radio Frequency Pulse Designs for Magnetic Resonance at High Field. [Internet] [Doctoral dissertation]. Vanderbilt University; 2011. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/1803/11602.

Council of Science Editors:

Moore JE. Radio Frequency Pulse Designs for Magnetic Resonance at High Field. [Doctoral Dissertation]. Vanderbilt University; 2011. Available from: http://hdl.handle.net/1803/11602

University of Illinois – Urbana-Champaign

24. Ngo, Giang-Chau. Model-based reconstruction for correcting magnetic susceptibility-induced artifacts in magnetic resonance imaging.

Degree: PhD, Bioengineering, 2018, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/101258

► While magnetic susceptibility is an essential contrast mechanism in magnetic resonance imaging (MRI), it also causes significant disruptions to the imaging process. Strong differences in… (more)

▼ While magnetic susceptibility is an essential contrast mechanism in magnetic resonance imaging (MRI), it also causes significant disruptions to the imaging process. Strong differences in magnetic susceptibility exist at the air and tissue interfaces in the brain, resulting in a magnetic field distribution across the brain which is called the background magnetic field. Although many methods have been developed to correct the image distortions and signal loss due to the background magnetic field, there has not been a thorough analysis of the impact of the spatial gradients of this background magnetic field on MR imaging. This dissertation demonstrates, models, and corrects the important effects of the background magnetic field and the corresponding susceptibility-induced magnetic field gradients (SI-MFGs) in MRI. The background SI-MFGs have particularly a strong impact on applications using gradient echo acquisitions, such as functional MRI (fMRI) and R2* mapping. In this work, SI-MFGs are shown to lead to a non-uniform fMRI sensitivity through the brain due to induced echo time shifts. A method based on estimated background magnetic field maps and SI-MFG maps is used to predict the impact of SI-MFGs on the fMRI sensitivity. Using the proposed approach, the potential bias introduced by the background SI-MFGs is evaluated for an aging study, by looking at the magnetic field distribution differences between younger and older subjects. Although aging introduces changes in the magnetic field distribution across the brain, I demonstrate that the magnitude of the changes between the two groups is small, and thus no measurable age-related bias in fMRI contrast due SI-MFGs is expected at 3 T. Background SI-MFGs also lead to bias in R2* mapping. R2* values are crucial for applications such as quantitative functional MRI and relative cerebral blood volume estimation. Therefore, for these applications, it is important to obtain R2* estimates which are not dependent on the background magnetic field distribution. However, background SI-MFGs can lead to an overestimation of R2* values if standard estimation approaches are used. A model capturing the SI-MFG effects on the R2* decay is developed and implemented in this work. A novel k-space-based method using this signal model and a joint estimation framework is developed to obtain R2* estimates free of SI-MFG bias. I also demonstrate that accurate modeling of the background magnetic field effects also enables faster acquisitions for quantitative susceptibility mapping. Fast imaging can be achieved by using long readout imaging but at the expense of increased artifacts induced by the background magnetic field. Correcting for the background field effects is crucial to provide accurate magnitude and phase images. In this work, a model-based reconstruction framework is combined with an efficient 3D spiral-in acquisition for susceptibility mapping. Susceptibility maps free of background magnetic field artifact are obtained at a resolution of 1 x 1 x 1 mm3 in 46 s, which is 17 times… Advisors/Committee Members: Sutton, Bradley P. (advisor), Sutton, Bradley P. (Committee Chair), Insana, Michael (committee member), Liang, Zhi-Pei (committee member), Sadaghiani, Sepideh Friberg (committee member).

Subjects/Keywords: Magnetic Resonance Imaging; Magnetic susceptibility; Magnetic field inhomogeneity; Model-based imaging reconstruction; Functional MRI; R2* estimation; Quantitative susceptibility mapping

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ngo, G. (2018). Model-based reconstruction for correcting magnetic susceptibility-induced artifacts in magnetic resonance imaging. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/101258

Chicago Manual of Style (16^th Edition):

Ngo, Giang-Chau. “Model-based reconstruction for correcting magnetic susceptibility-induced artifacts in magnetic resonance imaging.” 2018. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 06, 2021. http://hdl.handle.net/2142/101258.

MLA Handbook (7^th Edition):

Ngo, Giang-Chau. “Model-based reconstruction for correcting magnetic susceptibility-induced artifacts in magnetic resonance imaging.” 2018. Web. 06 Mar 2021.

Vancouver:

Ngo G. Model-based reconstruction for correcting magnetic susceptibility-induced artifacts in magnetic resonance imaging. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2018. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/2142/101258.

Council of Science Editors:

Ngo G. Model-based reconstruction for correcting magnetic susceptibility-induced artifacts in magnetic resonance imaging. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2018. Available from: http://hdl.handle.net/2142/101258

25. Kar,Chitra. A study of some nonlinear interactions of kinetic alfven waves;.

Degree: Data not available, 2015, Gujarat University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/48552

Abstract Available

Data not available

Advisors/Committee Members: Sen,Abhijit.

Subjects/Keywords: Alfven; Frequency; Inhomogeneity; Kinetic; Nonlinear; Parametric; Plasmas; Ponderomotive

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kar,Chitra. (2015). A study of some nonlinear interactions of kinetic alfven waves;. (Thesis). Gujarat University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/48552

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kar,Chitra. “A study of some nonlinear interactions of kinetic alfven waves;.” 2015. Thesis, Gujarat University. Accessed March 06, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/48552.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kar,Chitra. “A study of some nonlinear interactions of kinetic alfven waves;.” 2015. Web. 06 Mar 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

Kar,Chitra. A study of some nonlinear interactions of kinetic alfven waves;. [Internet] [Thesis]. Gujarat University; 2015. [cited 2021 Mar 06]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/48552.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kar,Chitra. A study of some nonlinear interactions of kinetic alfven waves;. [Thesis]. Gujarat University; 2015. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/48552

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Not specified: Masters Thesis or Doctoral Dissertation

26. Kulkarni,Vaman H. Studies in wave particle interactions;.

Degree: Data not available, 2015, Gujarat University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/48623

Abstract Not Available

Data not available

Advisors/Committee Members: Das,Anath Chandra.

Subjects/Keywords: Dynamics; Gerenkov; Inhomogeneity; Nagnetosphere; Wave-Particle; Whistlers

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

H, K. (2015). Studies in wave particle interactions;. (Thesis). Gujarat University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/48623

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

H, Kulkarni,Vaman. “Studies in wave particle interactions;.” 2015. Thesis, Gujarat University. Accessed March 06, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/48623.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

H, Kulkarni,Vaman. “Studies in wave particle interactions;.” 2015. Web. 06 Mar 2021.

Vancouver:

H K. Studies in wave particle interactions;. [Internet] [Thesis]. Gujarat University; 2015. [cited 2021 Mar 06]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/48623.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

H K. Studies in wave particle interactions;. [Thesis]. Gujarat University; 2015. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/48623

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Texas A&M University

27. Han, Sang-Ok. Investigation of surface inhomogeneity and estimation of the GOES skin temperature assimilation errors of the MM5 implied by the inhomogeneity over Houston metropolitan area.

Degree: PhD, Meteorology, 2005, Texas A&M University

URL: http://hdl.handle.net/1969.1/2505

► This study developed a parameterization method to investigate the impacts of inhomogeneous land surfaces on mesoscale model simulations using a high-resolution 1-d PBL model. Then,… (more)

▼ This study developed a parameterization method to investigate the impacts of inhomogeneous land surfaces on mesoscale model simulations using a high-resolution 1-d PBL model. Then, the 1-d PBL model was used to investigate the inhomogeneity-caused model errors in applying the GOES satellite skin temperature assimilation technique into the MM5 over the Houston metropolitan area (HOU). In order to investigate the surface inhomogeneity impacts on the surface fluxes and PBL variables over HOU, homo- and inhomogeneous 1-d PBL model simulations were performed over HOU and compared to each other. The 1-d PBL model was constructed so that the surface inhomogeneities were able to be represented within model grid elements using a methodology similar to Avissar and Pielke (1989). The surface inhomogeneities over HOU were defined using 30-m resolution land cover data produced by Global Environment Management (GEM), Inc. The inhomogeneity parameterization method developed in the 1-d model was applied to a standard MM5 simulation to test the applicability of the parameterization to 3-d mesoscale model simulations. From the 1-d simulations it was inferred that the surface inhomogeneities would enhance the sensible heat flux by about 36 % and reduce the latent heat flux by about 25 %, thereby inducing the warmer (0.7 %) and drier (-1.0 %) PBL and the colder and moister PBL top induced by greater turbulent diffusivities. The 3-d application of the inhomogeneity parameterization indicated consistent results with the 1-d in general, with additional effects of advection and differential local circulation. The original GOES simulation was warmer compared to observations over HOU than over surrounding areas. The satellite data assimilation itself would lead to a warm bias due to erroneous estimation of gridpoint-mean skin temperature by the satellite, but 1-d simulations indicate that the impact of this error should be much weaker than what was observed. It seems that, unless the already existing warm and dry bias of the MM5 is corrected, the inhomogeneity parameterization in the MM5 would adversely affect the MM5 performance. Therefore, consideration of the surface inhomogeneities in the urban area needs to be confined to the GOES skin temperature retrieval errors at the moment. Advisors/Committee Members: Nielsen-Gammon, John W. (advisor), Cahill, Anthony (committee member), Zhang, Fuqing (committee member), North, Gerald R. (committee member).

Subjects/Keywords: Inhomogeneity; GOES; MM5; PBL; Skin Temperature; Assimilation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Han, S. (2005). Investigation of surface inhomogeneity and estimation of the GOES skin temperature assimilation errors of the MM5 implied by the inhomogeneity over Houston metropolitan area. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/2505

Chicago Manual of Style (16^th Edition):

Han, Sang-Ok. “Investigation of surface inhomogeneity and estimation of the GOES skin temperature assimilation errors of the MM5 implied by the inhomogeneity over Houston metropolitan area.” 2005. Doctoral Dissertation, Texas A&M University. Accessed March 06, 2021. http://hdl.handle.net/1969.1/2505.

MLA Handbook (7^th Edition):

Han, Sang-Ok. “Investigation of surface inhomogeneity and estimation of the GOES skin temperature assimilation errors of the MM5 implied by the inhomogeneity over Houston metropolitan area.” 2005. Web. 06 Mar 2021.

Vancouver:

Han S. Investigation of surface inhomogeneity and estimation of the GOES skin temperature assimilation errors of the MM5 implied by the inhomogeneity over Houston metropolitan area. [Internet] [Doctoral dissertation]. Texas A&M University; 2005. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/1969.1/2505.

Council of Science Editors:

Han S. Investigation of surface inhomogeneity and estimation of the GOES skin temperature assimilation errors of the MM5 implied by the inhomogeneity over Houston metropolitan area. [Doctoral Dissertation]. Texas A&M University; 2005. Available from: http://hdl.handle.net/1969.1/2505

University of Waterloo

28. Rashidi, Sepehr. A Subclass of Exceptional Parallel Self-similar G2 Cosmologies.

Degree: 2019, University of Waterloo

URL: http://hdl.handle.net/10012/14632

► We perform a qualitative and asymptotic analysis of a particular class of cosmological models, namely the exceptional G2 perfect fluid and vacuum models that are… (more)

Subjects/Keywords: general relativity; cosmology; inhomogeneous; self-similar; G2; inhomogeneity; orthonormal tetrad; isometry group; perfect fluid; vacuum; similarity group; H3

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rashidi, S. (2019). A Subclass of Exceptional Parallel Self-similar G2 Cosmologies. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/14632

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Rashidi, Sepehr. “A Subclass of Exceptional Parallel Self-similar G2 Cosmologies.” 2019. Thesis, University of Waterloo. Accessed March 06, 2021. http://hdl.handle.net/10012/14632.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Rashidi, Sepehr. “A Subclass of Exceptional Parallel Self-similar G2 Cosmologies.” 2019. Web. 06 Mar 2021.

Vancouver:

Rashidi S. A Subclass of Exceptional Parallel Self-similar G2 Cosmologies. [Internet] [Thesis]. University of Waterloo; 2019. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/10012/14632.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rashidi S. A Subclass of Exceptional Parallel Self-similar G2 Cosmologies. [Thesis]. University of Waterloo; 2019. Available from: http://hdl.handle.net/10012/14632

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

UCLA

29. Zhong, Xinran. Improving the Quantitative Interpretation of Multi-parametric MRI (mp-MRI) in Prostate Cancer.

Degree: Physics and Biology in Medicine 009Y, 2019, UCLA

URL: http://www.escholarship.org/uc/item/6wt265bq

► Purpose Prostate cancer (PCa) is the second leading cause of cancer-related death in men in the United States. The accurate diagnosis of PCa is crucial… (more)

▼ Purpose Prostate cancer (PCa) is the second leading cause of cancer-related death in men in the United States. The accurate diagnosis of PCa is crucial for proper treatment decision. Although biopsy is still the gold standard for diagnosis, it is limited to low sensitivity and invasiveness. On the other hand, as a non-invasive imaging tool, multi-parametric MRI (mp-MRI) has excellent potential in PCa diagnosis such as detection and stratification of aggressiveness. The mp-MRI includes both anatomical and functional information to be able to provide a comprehensive characterization of the tissue. However, diagnosis with mp-MRI is limited to inconsistent and qualitative interpretation. Clinically, the evaluation of mp-MRI is often through a standardized scoring system, PIRADS v2, which can lead to high inter- and intra-observer variability, and with a large amount of data for each case, the diagnosis process can be time-consuming. In order to get a more consistent quantitative evaluation, there are mainly two ways to utilize algorithms to help the diagnosis. The first one is creating quantitative biomarkers through mathematical models proposed based on assumption and understanding of physics and physiology, such as pharmacokinetic models for quantitative dynamic contrast-enhanced (DCE) MRI. The second one is using a machine learning technique to train a system with existing data to get diagnosis prediction on new data. The purpose of this work is to improve the quantitative interpretation of mp-MRI in PCa diagnosis regarding consistency and accuracy.Methods To evaluate existing B1+ estimation techniques to achieve a more consistent pre-contrast T1 estimation for quantitative DCE- MRI, 21 volunteers were prospectively recruited and scanned twice on two 3T MRI scanners, resulting in 84 variable flip angle (VFA) T1 exams. Two B1+ mapping techniques, including reference region variable flip angle (RR-VFA) and saturated turbo FLASH (satTFL), were used for B1+ correction, and T1 maps with and without B1+ correction were tested for the intra-scanner repeatability and inter-scanner reproducibility. Volumetric regions of interest were drawn on the transition zone, peripheral zone of the prostate and the obturator internus left and right muscles in the corresponding slices. The average T1 within each ROI for each scan was compared for both intra- and inter-scanner variability using concordance correlation coefficient and Bland-Altman plot. To simplify B1+ compensation for quantitative DCE MRI in clinical and clinical research settings, an analytical B1+ correction method is proposed using a Taylor series approximation to the steady-state spoiled gradient echo signal equation. The proposed approach only requires B1+ maps and uncorrected pharmacokinetic (PK) parameters as the input, and was evaluated using a prostate digital reference object (DRO) and 82 in-vivo prostate DCE-MRI cases. The approximated analytical correction was compared with the ground truth PK parameters in simulation, and compared with the reference numerical…

Subjects/Keywords: Biophysics; B1+ inhomogeneity; clinically significant lesion; deep transfer learning; multi-parametric MRI; prostate cancer; quantitative DCE MRI

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zhong, X. (2019). Improving the Quantitative Interpretation of Multi-parametric MRI (mp-MRI) in Prostate Cancer. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/6wt265bq

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhong, Xinran. “Improving the Quantitative Interpretation of Multi-parametric MRI (mp-MRI) in Prostate Cancer.” 2019. Thesis, UCLA. Accessed March 06, 2021. http://www.escholarship.org/uc/item/6wt265bq.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhong, Xinran. “Improving the Quantitative Interpretation of Multi-parametric MRI (mp-MRI) in Prostate Cancer.” 2019. Web. 06 Mar 2021.

Vancouver:

Zhong X. Improving the Quantitative Interpretation of Multi-parametric MRI (mp-MRI) in Prostate Cancer. [Internet] [Thesis]. UCLA; 2019. [cited 2021 Mar 06]. Available from: http://www.escholarship.org/uc/item/6wt265bq.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhong X. Improving the Quantitative Interpretation of Multi-parametric MRI (mp-MRI) in Prostate Cancer. [Thesis]. UCLA; 2019. Available from: http://www.escholarship.org/uc/item/6wt265bq

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

30. Smale, Peter Rich. Observations and inhomogeneity in cosmology.

Degree: Physics and Astronomy, 2012, University of Canterbury

URL: http://hdl.handle.net/10092/6868

► We interpret distance measurements from nearby galaxies, type Ia supernovae, and gamma-ray bursts in the light of a cosmological model that incorporates a spatial averaging… (more)

Subjects/Keywords: cosmology; timescape model; observational cosmology; inhomogeneity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Smale, P. R. (2012). Observations and inhomogeneity in cosmology. (Thesis). University of Canterbury. Retrieved from http://hdl.handle.net/10092/6868

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Smale, Peter Rich. “Observations and inhomogeneity in cosmology.” 2012. Thesis, University of Canterbury. Accessed March 06, 2021. http://hdl.handle.net/10092/6868.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Smale, Peter Rich. “Observations and inhomogeneity in cosmology.” 2012. Web. 06 Mar 2021.

Vancouver:

Smale PR. Observations and inhomogeneity in cosmology. [Internet] [Thesis]. University of Canterbury; 2012. [cited 2021 Mar 06]. Available from: http://hdl.handle.net/10092/6868.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Smale PR. Observations and inhomogeneity in cosmology. [Thesis]. University of Canterbury; 2012. Available from: http://hdl.handle.net/10092/6868

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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