Conventional convergence acceleration techniques for the SCF procedure like the direct inversion in the iterative subspace and the level-shifting can not be applied in the general case of non-Hermitian Fock operators. The commutator of the Fock matrix and the density matrix do not vanish upon convergence of nonHermitian SCF equations and hence the usual error vector choice is not applicable. In...

Nowadays computer graphics hardware presents a series of characteristics, such as AGP memory, vertex cache, etc., that can be used for real-time rendering. The aim of this paper is to conduct a comparative study of different techniques that are shown in the OpenGL graphics standard together with hardware features that enable the visualization of the geometry of complex objects to be accelerated...

Acknowledgements I would like to express my deep and sincere gratitude to my supervisor, Professor Valeria Simoncini from the University of Bologna; her guidance has been of great value in this study. I am deeply grateful to Professor Luciano Lopez from the University of Bari for his important support throughout this work and his paternal advices. My sincere thanks to Professor Tiziano Politi, ...

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Computing displacement from measured acceleration is important for understanding the characteristics of an earthquake. However, to obtain such displacement with a good accuracy is difficult. It is partly because the low-frequency component dominating the behavior of the displacement is often affected by the sensor’s tilt and the measurement error. To avoid these, a high pass filter is usually a...

PURPOSE High-resolution intravascular (IV) MRI is susceptible to degradation from physiological motion and requires high frame-rates for true endoscopy. Traditional cardiac-gating techniques compromise efficiency by reducing the effective scan rate. Here we test whether compressed sensing (CS) reconstruction and ungated motion-compensation using projection shifting, could provide faster motion-...

The next generation of computational science applications will require numerical solvers that are both reliable and capable of high performance on projected exascale platforms. In order to meet these goals, solvers must be resilient to soft and hard system failures, provide high concurrency on heterogeneous hardware configurations, and retain numerical accuracy and efficiency. This work focuses...

Within the recent years clock rates of modern processors stagnated while the demand for computing power continued to grow. This applied particularly for the fields of life sciences and bioinformatics, where new technologies keep on creating rapidly growing piles of raw data with increasing speed. The number of cores per processor increased in an attempt to compensate for slight increments of cl...

Recently it was shown by Nesterov (2011) that techniques form convex optimization can be used to successfully accelerate simple derivativefree randomized optimization methods. The appeal of those schemes lies in their low complexity, which is only Θ(n) per iteration—compared to Θ(n) for algorithms storing second-order information or covariance matrices. From a high-level point of view, those ac...

The paper describes a simple analytical framework to be used when designing control algorithms for systems of specific type – in which the state derivatives go in feedback as accelerometer signals, and the overall controller explicitly exhibits an algebraic disturbance feedback loop. A simplified hydrofoil craft linear model is treated as an example. The method proposed combines all the approac...