Nonparametric Bayesian methods in robotic vision

In this dissertation non-parametric Bayesian methods are used in the application of robotic vision. Robots make use of depth sensors that represent their environment using point clouds. Non-parametric Bayesian methods can (1) determine how good an object is recognized, and (2) determine how many objects a particular scene contains. When there is a model available for the object to be recognized and the nature of perceptual error is known, a Bayesian method will act optimally.In this dissertation Bayesian models are developed to represent geometric objects such as lines and line segments (consisting out of points). The infinite line model and the infinite line segment model use a non-parametric Bayesian model, to be precise, a Dirichlet process, to represent the number of objects. The line or the line segment is represented by a probability distribution. The lines can be represented by conjugate distributions and then Gibbs sampling can be used. The line segments are not represented by conjugate distributions and therefore a split-merge sampler is used.A split-merge sampler fits line segments by assigning points to a hypothetical line segment. Then it proposes splits of a single line segment or merges of two line segments. A new sampler, the triadic split-merge sampler, introduces steps that involve three line segments. In this dissertation, the new sampler is compared to a conventional split-merge sampler. The triadic sampler can be applied to other problems as well, i.e., not only problems in robotic perception.The models for objects can also be learned. In the dissertation this is done for more complex objects, such as cubes, built up out of hundreds of points. An auto-encoder then learns to generate a representative object given the data. The auto-encoder uses a newly defined reconstruction distance, called the partitioning earth mover’s distance. The object that is learned by the auto-encoder is used in a triadic sampler to (1) identify the point cloud objects and to (2) establish multiple occurrences of those objects in the point cloud.Algorithms and the Foundations of Software technolog

Объем остаточной тиреоидной ткани и эффективность постоперационной радиойодтерапии больных с дифференцированными формами рака щитовидной железы

Резюме. У 210 больных с дифференцированными формами рака щитовидной железы изучено влияние массы участков остаточной ткани щитовидной железы (ОТЩЖ) на эффективность радиойодтерапии (РЙТ). Через 4–6 нед после хирургического лечения выполняли диагностическую сцинтиграфию с 70–80 МБк 131I, по данным которой на основании эллипсоидной модели рассчитывали объем ОТЩЖ. РЙТ проводили активностями 1,9–4,7 ГБк, контрольную сцинтиграфию выполняли через 4–6 мес. Эффективность первого курса РЙТ при объеме ОТЩЖ 1 см3 и менее составляла 88,9%, при объеме более 4 см3 — 69,3% (р < 0,05). Установлена достоверная корреляция между объемом ОТЩЖ и эффективностью первого курса РЙТ. При наличии нескольких участков ОТЩЖ эффективность РЙТ определяется не столько их количеством и суммарным объемом, сколько объемом каждого участка. Ключевые слова: дифференцированный рак щитовидной железы, тиреоидэктомия, радиойодтерапия, остаточная ткань щитовидной железы.Summary. The influence of the mass of the residual thyroid tissue (RTT) on the efficacy of radioiodine therapy (RT) was investigated in 210 patients with differentiated forms of thyroid cancer (DFTC). 4 to 6 weeks after surgery, diagnostic 131J scintigraphy (70–80 MBq) was applied. On the basis of data obtained, the RTT size was measured based on an ellipsoidal model. Activities applied in RT ranged between 1,9–4,7 GBq; control scintigraphy was performed in 4 to 6 months. The efficacy of the first RT course was 88,9% in patients with RTT of 1 cm3 or smaller and 69,3% in patients with RTT of 4 cm3 or larger (р<0,05). A significant correlation was found between the size of RTT and the efficacy of the first RT course. In cases where there were several RTT areas, the RT efficacy depended on the overall size of each area rather than on the number of such areas. Key Words: differentiated thyroid cancer, thyreoidectomy, radioiodine therapy, residual thyroid tissue

Septal ablation in hypertrophic obstructive cardiomyopathy improves systolic myocardial function in the lateral (free wall): a follow-up study using CMR tissue tagging and 3D strain analysis

Aims: Alcohol septal ablation (ASA) has been successful in the treatment of symptomatic hypertrophic obstructive cardiomyopathy (HOCM). The aim of this study is to evaluate the effects of ethanol-induced myocardial infarcts on regional myocardial function using cardiac magnetic resonance (CMR) tissue tagging and 3-dimensional (3D) strain analysis. Methods and results: In nine patients (age 52±15 years) who underwent ASA, CMR was performed prior to and 6 months after the procedure. Regional myocardial mass was evaluated using cine imaging. Myocardial tagging was used to calculate systolic 3D myocardial strain values. These strain values were used to calculate the shortening index (SI), a robust parameter for myocardial contraction. Maximum end-systolic (ES) SI and systolic SI rate were quantified in three circumferential segments: septum, adjacent, and remote (lateral) myocardium. Compared with baseline, septal and non-septal mass decreased at follow-up (from 72±27 to 59±21 g; P=0.008 and from 131±34 to 109±30 g; P=0.008, respectively). In the septum, maximum ES SI and SI rate remained unchanged after ASA. In adjacent myocardium, ES SI remained unchanged, whereas SI rate improved (from -56.5±21.1 to -70.0±16.7%/s; P=0.02). Both ES SI and SI rate improved significantly in remote myocardium (from -16.9±2.8 to -18.8±3.2%; P=0.02 and from -70.3±9.2 to -86.1±15.0%/s; P=0.01, respectively). Conclusion: Reduction of left ventricular (LV) outflow tract obstruction in symptomatic HOCM is associated with a significant reduction in myocardial mass and improvement of intramural systolic function in the lateral (remote) wall, indicating reversed LV remodelling. © The European Society of Cardiology 2006. All rights reserved

ADVANCE AUSTRALIA FAIR? (IN)EQUALITY, PROSPERITY AND SUSTAINABILITY IN SHAPING AUSTRALIA’S FUTURE

Scholarships & Prizes Office. University of Sydne

Nonparametric Segment Detection

Algorithms and the Foundations of Software technolog

Impact of alcohol septal ablation on left anterior descending coronary artery blood flow in hypertrophic obstructive cardiomyopathy

Objectives: The aim of this study was to evaluate the effects of alcohol septal ablation (ASA) on coronary blood flow in symptomatic hypertrophic obstructive cardiomyopathy (HOCM) using cardiac MR (CMR) coronary flow measurements. Background: CMR flow mapping enables quantification of coronary blood flow in a noninvasive way. Both left ventricular outflow tract (LVOT) gradient reduction and myocardial scarring after ASA are expected to influence left anterior descending (LAD) coronary blood flow. Methods: Cine, contrast-enhanced (CE) imaging and breath-hold CMR phase contrast velocity mapping were performed at baseline and 1 and 6 months after ASA in seven patients. Changes of coronary blood flow were related to left ventricular (LV) mass reduction, enzyme release, volume of ethanol administered, LVOT gradient reduction, and LV rate pressure product (LVRPP). Results: A significant mass reduction was observed bothin the target septal myocardium and in the total myocardium (both P < 0.01). Mean myoca