to make an accurate estimation of the uptake of radioactivity in an organ using the conjugate view method, corrections of physical factors, such as background activity, scatter, and attenuation are needed. the aim of this study was to evaluate the accuracy of four different methods for background correction in activity quantification of the heart in myocardial perfusion scans. the organ activit...

The non-Markovianity of the stochastic process called quantum semi-Markov (QSM) is studied using a recently proposed quantification memory based on deviation from semigroup evolution, that provides unified description divisible and indivisible channels. This shown to bring out property QSM processes exhibit effects even in CP-divisible regime, agreement with an earlier result. An operational me...

Wildfires are one of the major disasters among many and responsible for more than 6 million acres burned in United States alone every year. Accurate, insightful, timely wildfire detection is needed to help authorities mitigate prevent further destruction. Uncertainty quantification always a crucial part natural disasters, such as wildfires, modeling products can be misinterpreted without proper...

MULTI-FIDELITY STOCHASTIC COLLOCATION Maziar Raissi, PhD George Mason University, 2013 Dissertation Director: Dr. Padmanabhan Seshaiyer Over the last few years there have been dramatic advances in our understanding of mathematical and computational models of complex systems in the presence of uncertainty. This has led to a growth in the area of uncertainty quantification as well as the need to ...

The simultaneous perturbation stochastic approximation (SPSA) algorithm is modified to obtain a stochastic Gaussian search direction (SGSD) algorithm for automatic history matching. The search direction in the SGSD algorithm is obtained by simultaneously perturbing the reservoir model with unconditional realizations from a Gaussian distribution. This search direction has two nice properties: (1...

A variety of methods is available to quantify uncertainties arising within the modeling of flow and transport in carbon dioxide storage, but there is a lack of thorough comparisons. Usually, raw data from such storage sites can hardly be described by theoretical statistical distributions since only very limited data is available. Hence, exact information on distribution shapes for all uncertain...