60 research outputs found

    MATLAB Implementation of a Multigrid Solver for Diffusion Problems: : Graphics Processing Unit vs. Central Processing Unit

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    Graphics Processing Units are immensely powerful processors and for variety applications they outperform the Central Processing Unit, CPU. The recent generations of GPU’s have a flexible architecture than older generations and programming interface more user friendly, which makes them better suited for general purpose programming. A high end GPU can give a desktop computer the same computational power as a small cluster of CPU’s. Speedup of applications by using the GPU has been shown in a variety of research fields, including medicine, finance and earth science. 3D seismic imaging is extensively used in oil exploration, and imaging complex geological areas is heavy computational task involving terabytes of data. Seismic imaging software that utilizes GPU’s is being developed by companies such as SeismicCity. They found that 20x performance increase can be achieved by utilizing GPU’s in their computer setup. In this thesis it is shown that the GPU architecture is well suited for solving partial differential equations on structured grids. A parallel multigrid method algorithm is implemented using Jacket that can harness the computational power of the GPU. Jacket uses MATLAB syntax, which allow for more rapid development of algorithms. This does, however, come at a price, implementations that are developed in high level languages is not as efficient as implementations developed in low level languages such as C. The ideas used in multigrid have been adapted to solve a broad spectrum of problems that involves structures that do not necessarily resemble any form of physical grid. They can for example be used to solve problems characterized by matrix structures, particle structures and lattice structures. The collection of methods that build on the same ideas as the multigrid method is often called multilevel methods, but there is no official unified term for these methods. The multigrid algorithm implemented in this thesis efficiently solves Poisson problems for homogenous systems in 2 and 3 dimensions. The GPU implementation is 60 to 70 times faster than the equivalent CPU implementation, and can solve systems of size 2573 in less than a second. Poisson solvers can be used to solve a variety of physical problems either as a stand alone solver or as a part of another solver. In this thesis it is shown that it can be used in an application where porous convection is simulated. Porous convection can describe migration of ground water and hydrocarbons in the earth’s crust

    Current, April 21, 1977

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    https://irl.umsl.edu/current1970s/1209/thumbnail.jp

    The News, January 28, 1949

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    The News, January 21, 1949

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    The Legal Culture of Appropriation Art: The Future of Copyright in the Remix Age

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    1 full d'un mapa en 86 fulls, col. - 1a ed. Es van publicar 72 fulls de la sèrie, entre 2005 i 2007. Hi ha una desena de fulls d'una ed. preliminar de 2004 (sortides de plotter). - Cada mapa conté la llegenda (hàbitats vegetals, etc.), un mapa guia i un esquema litològic. - Data d'elaboració de la informació.1:50 00

    Investigating the Link Between Executive Function and Creativity in School Aged Children

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    The primary purpose of this research was to examine links between executive function (i.e., EF or conscious control) and creativity in school aged children. To accomplish this, participants completed measurements of creativity (i.e., Alternative Uses) and EF (i.e., the Backwards Digit Span to test working memory, the Delay of Gratification task to test inhibition). I also examined whether a creative manipulation (i.e., free coloring or coloring task-relevant materials) would impact EF performance in the Dimensional Card Change Sort (DCCS) focused on cognitive flexibility. While I did not find evidence for a relationship between my measures of EF and creativity, I found that those who were low in certain creative components (i.e., the ability to switch between categories called flexibility, the ability to generate a number of unique ideas called atypical fluency, and originality) performed better on the DCCS when allowed to freely color before the DCCS, while those who performed higher in creative measures generally did not benefit from a creative manipulation before the task. This suggests that those who are low in creativity may experience EF benefits from adding unstructured creative activities before a task

    Spartan Daily, November 4, 1949

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    Volume 38, Issue 22https://scholarworks.sjsu.edu/spartandaily/11289/thumbnail.jp

    Northern Junket, Vol. 11, No. 1

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    The Ralph Page collection of country dance materials was gathered by Ralph Page and spans the years 1778-1989

    The Ledger & Times, November 18, 1937

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