Indiana University-Purdue University Indianapolis (IUPUI) / A Multigraph is a set of graphs with a common set of nodes but different sets of edges. Multigraph visualization has not received much attention so far. In this thesis, I will introduce an interactive application in brain network data analysis that has a strong need for multigraph visualization. For this application, multigraph was used to represent brain connectome networks of multiple human subjects. A volumetric data set was constructed from the matrix representation of the multigraph. A volume visualization tool was then developed to assist the user to interactively and iteratively detect network features that may contribute to certain neurological conditions. I applied this technique to a brain connectome dataset for feature detection in the classification of Alzheimer's Disease (AD) patients. Preliminary results showed significant improvements when interactively selected features are used.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18501号 / 医博第3921号 / 新制||医||1005(附属図書館) / 31387 / 京都大学大学院医学研究科医学専攻 / (主査)教授 千葉 勉, 教授 横出 正之, 教授 川口 義弥 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20567号 / 医博第4252号 / 新制||医||1022(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 古川 壽亮, 教授 髙橋 良輔, 教授 富樫 かおり / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine. Johannesburg, October 2017. / Background: Positron Emission Tomography (PET) is an imaging modality that guides the revascularization management of patients with left ventricular systolic dysfunction secondary to coronary artery disease. Segments of the myocardium demonstrating reduced perfusion and increased or preserved 18FFluorodeoxyglucose (18F-FDG) uptake are considered to be viable and thus suitable for revascularization. The aim of our study was to determine the prevalence of myocardial viability as determined by FDG-PET in our local cohort and to compare our prevalence of myocardial viability to data published elsewhere. Methods: We retrospectively reviewed 240 consecutive 99mTc-sestamibi myocardial perfusion Gated Single Photon Emission Tomography (SPECT) and 18FFDG PET reports of patients referred for evaluation of myocardial viability between January 2009 and June 2015. Results: 236 patients met the inclusion criteria. There were 194 (82.2%) males. The mean age was 59.1 (SD 11.0) years. A total of 4012 segments of the left ventricle were analyzed on the gated SPECT and reduced perfusion was noted in 1862 (46.4%) segments. Perfusion-metabolism mismatch (viable myocardium) was observed in 586 (31.5%) out of 1862 perfusion defects. The prevalence of myocardial viability in the study population was 61.4%. On the multivariate logistic regression model, aspirin intake [OR:0.37; CI:0.16-0.83; p=0.016] and hypertension [OR:0.26; CI:0.12-0.58; p=0.001] were associated with the presence of viable myocardium. Smoking was associated with the likelihood of having non-viable myocardium [OR:2.31; CI:1.01-5.29; p=0.048] Conclusion: The prevalence of myocardial viability as detected by 18F FDG PET in our local cohort is similar to prevalence rates reported in the developed world. / LG2018

Broiler birds have drastically increased in size over the past few decades through improvements in genetic selection. Physical measurements such as surface area, volume and physical dimensions are needed information in the construction of animal facilities and developing management guidelines. The objective of this study was to develop a three-dimensional scanning methodology to characterize surface area and envelope volume of poultry, livestock, and equine using a commercially available 3D digitizer system. The digitizing system used phase shift moiré to capture images of three test cylinders, four fiberglass animal models, and a live broiler bird. These images were spliced into physical models using image processing software. System accuracy (< 2%) was verified with cylinder models. Recommended camera orientations and placements were established with each species by the use of fiberglass models. The methods will have to be fine-tuned for live animals as observed in the live broiler test.

The Mississippi Institute for Forest Inventory (MIFI) is the only cost-effective large-scale forest inventory system in the United States with sufficient precision for producing reliable volume/weight/biomass estimates for small working circle areas (procurement areas). When forest industry is recruited to Mississippi, proposed working circles may overlap existing boundaries of bordering states leaving a gap of inventory information, and a remote sensing-based system for augmenting missing ground inventory data is desirable. The feasibility of obtaining acceptable cubic foot volume estimates from a Landsat-derived volume estimation model (Wilkinson 2011) was assessed by: 1) an initial study to temporally validate Landsat-derived cubic foot volume outside bark to a pulpwood top estimates in comparison with MIFI ground truth inventory plot estimates at two separate time periods, and 2) re-developing a regression model based on remotely sensed imagery in combination with available MIFI plot data. Initial results failed to confirm the relationships shown in past research between radiance values and volume estimation. The complete lack of influence of radiance values in the model led to a re-assessment of volume estimation schemes. Data outlier trimming manipulation was discovered to lead to false relationships with radiance values reported in past research. Two revised volume estimation models using age, average stand height, and trees per-acre and age and height alone as independent variables were found sufficient to explain variation of volume across the image. These results were used to develop a procedure for other remote sensing technologies that could produce data with sufficient precision for volume estimation where inventory data are sparse or non-existent.

Dissolutional voids in the subsurface were examined from three different viewpoints. First, analysis of pseudokarst features on San Salvador Island, Bahamas, uncovered the involvement of organics in the cementation and porosity generation process. This organic material was analyzed using SEM, TEM, and in thin section. While the actual role of organics in the cementation process could not be determined using these tools, the abundance of the material was documented. Holocene samples appear to have more organics than Pleistocene samples. The abundance of this material should have an effect on isotope analyses and needs to be considered in future work on meteoric cements and the environments where they form. Second, work on Mallorca Island, Spain, demonstrated how the placement and abundance of exposed caves could predict subsurface cave distributions. This work measured caves along exposed coastlines and in protected areas known as calas. Results found that caves within the calas have larger volumes and aerial footprints than caves on the exposed cliffs. The cave distributions showed that calas had to form prior to cave formation. Several paleo-slump features were observed and are believed to be the result of collapsed Tortonian flank margin caves, which were later inilled with Messinian sediments, using the caves as limited accommodation space, resulting in these sediment layers unaffected by the collapse further up section. Third, the current method of cave data manipulation to produce cave areal footprints and volume was found to be incorrect and in need of a calibration mechanism. This calibration was determined by reviewing how Compass cave mapping software generates volume estimates, using shapes of known volumes. Cave surveying techniques were also reviewed to determine if survey protocol affected volume outputs. Surveying in straight lines, down the center of a passage, avoiding splay shots, and taking left, right, up and down measurements (LRUDs) were found to generate the most accurate volumes estimates using Compass. These protocols were used to remap caves from paper maps to generate correction factors. Propriety software was used that could “shrink wrap” a 3D cave map rendering to produced values for cave volume and porosity and rock porosity.

One area of forest biometrics that continues to progress is the development of statistical models as tools to describe tree taper. Taper models allow for the prediction of multiple tree level attributes including: diameter at any height, total tree stem volume, merchantable volume and height to any upper stem diameter from any lower stem height, individual log volumes, and subsequently total tree value. In this work, we generalize segmented regression taper models to include multiple segments and compare it to the traditional 3-Segment (2-Knot) models commonly observed in the forestry literature. We then focus on predicting a future realization of diameter given previously observed data. This is accomplished by comparing a segmented taper model under both the Generalized Algebraic Difference Approach (GADA) and Nonlinear Mixed Effects Models (NLMM) methodologies. Both the GADA and NLMM allow for predictions at the individual tree level of a future realization diameter given a differing number of observed height-diameter pairs. Finally, we explore the prediction and cost/benefit of total tree volume obtained from an integrated taper equation with the incorporation of tree specific random effects given differing observed height-diameter pairs.

A new implicit and compact optimization-based method is presented for high order derivative calculation for finite-volume numerical method on unstructured meshes. Highorder approaches to gradient calculation are often based on variants of the Least-Squares (L-S) method, an explicit method that requires a stencil large enough to accommodate the necessary variable information to calculate the derivatives. The new scheme proposed here is applicable for an arbitrary order of accuracy (demonstrated here up to 3rd order), and uses just the first level of face neighbors to compute all derivatives, thus reducing stencil size and avoiding stiffness in the calculation matrix. Preliminary results for a static variable field example and solution of a simple scalar transport (advection) equation show that the proposed method is able to deliver numerical accuracy equivalent to (or better than) the nominal order of accuracy for both 2nd and 3rd order schemes in the presence of a smoothly distributed variable field (i.e., in the absence of discontinuities). This new Optimization-based Gradient REconstruction (herein denoted OGRE) scheme produces, for the simple scalar transport test case, lower error and demands less computational time (for a given level of required precision) for a 3rd order scheme when compared to an equivalent L-S approach on a two-dimensional framework. For three-dimensional simulations, where the L-S scheme fails to obtain convergence without the help of limiters, the new scheme obtains stable convergence and also produces lower error solution when compared to a third order MUSCL scheme. Furthermore, spectral analysis of results from the advection equation shows that the new scheme is better able to accurately resolve high wave number modes, which demonstrates its potential to better solve problems presenting a wide spectrum of wavelengths, for example unsteady turbulent flow simulations.