765 resultados para Parallel computing


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Resumen basado en el de la publicaci??n

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We present algorithms for computing approximate distance functions and shortest paths from a generalized source (point, segment, polygonal chain or polygonal region) on a weighted non-convex polyhedral surface in which obstacles (represented by polygonal chains or polygons) are allowed. We also describe an algorithm for discretizing, by using graphics hardware capabilities, distance functions. Finally, we present algorithms for computing discrete k-order Voronoi diagrams

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Different procedures to obtain atom condensed Fukui functions are described. It is shown how the resulting values may differ depending on the exact approach to atom condensed Fukui functions. The condensed Fukui function can be computed using either the fragment of molecular response approach or the response of molecular fragment approach. The two approaches are nonequivalent; only the latter approach corresponds in general with a population difference expression. The Mulliken approach does not depend on the approach taken but has some computational drawbacks. The different resulting expressions are tested for a wide set of molecules. In practice one must make seemingly arbitrary choices about how to compute condensed Fukui functions, which suggests questioning the role of these indicators in conceptual density-functional theory

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An analytic method to evaluate nuclear contributions to electrical properties of polyatomic molecules is presented. Such contributions control changes induced by an electric field on equilibrium geometry (nuclear relaxation contribution) and vibrational motion (vibrational contribution) of a molecular system. Expressions to compute the nuclear contributions have been derived from a power series expansion of the potential energy. These contributions to the electrical properties are given in terms of energy derivatives with respect to normal coordinates, electric field intensity or both. Only one calculation of such derivatives at the field-free equilibrium geometry is required. To show the useful efficiency of the analytical evaluation of electrical properties (the so-called AEEP method), results for calculations on water and pyridine at the SCF/TZ2P and the MP2/TZ2P levels of theory are reported. The results obtained are compared with previous theoretical calculations and with experimental values

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Between 1895 and 1910 Barcelona saw a whole range of social, political and cultural changes due to the increasingly important emergence of the working masses. At the same time, the cinema arrived in Catalonia, becoming very quickly one of the favorite entertainments of the urban laboring population which was about creating a new culture opposed to the modernist and nineteenth-century elite .This is, broadly speaking, the context that serves as a starting point for a study of the role of cinema in shaping a mass audience in Barcelona, an analysis centered on new urban spaces intended for the leisure of the lower classes emerged with the birth of modern Barcelona, especially the “Paral•lel” avenue, whose opening in 1894 made even more apparent the great social tensions and existing inequalities in Barcelona’s society at the end of the century.

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El desarrollo eficiente y oportuno de las actividades propias de las empresas exige una constante renovación en su infraestructura, capacitación permanente de su staff, investigar nuevas tecnológicas y la asignación cada vez mayor del presupuesto para su área de TIC. Varios modelos de gestión han intentado suplir estas necesidades, entre los que se puede mencionar a: hosting, outsourcing, leasing, servicios profesionales, asesorías especializadas, entre otros. El modelo de gestión cloud computing y sus diversas opciones se está posicionando últimamente como la solución más viable y rápida de implementar. De ahí que, este proyecto se enfoca en el estudio de este modelo como una alternativa al modelo de gestión tradicional de servicios TIC, y toma como referencia para el desarrollo de esta tesis la situación actual de la infraestructura tecnológica de la Corporación ADC&HAS Management Ecuador S.A. No se pretende justificar al cloud como una solución definitiva, sino plantear este modelo como una alternativa útil a la realidad tecnológica de la Corporación, y en base a sus propiedades concluir que fue el modelo que mejor se ajustó a la estrategia institucional en términos: organizacionales, tecnológicos y financieros, por lo menos para los próximos cinco años. En los dos primeros capítulos se referencian algunos elementos conceptuales en los que se fundamenta las TIC y se mencionan ciertos parámetros que intervinieron en su evolución. El tercer capítulo describe a la Corporación; y en el capítulo cuarto se aplican los conceptos de los primeros capítulos reforzados con las experiencias publicadas en la revista Computerworld (2010 hasta la presente) y que permitieron evaluar los beneficios de los dos modelos de gestión y las razones para implementarlos o mantenerlos.

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Hoy en día el uso de las TIC en una empresa se ha convertido en indispensable sin importar su tamaño o industria a tal punto que ya no es una ventaja competitiva el simple hecho de usarla sino que la clave es determinar cuál es la mejor para la empresa. Existen en el mercado servicios en-línea que igualan o sobrepasan los estándares de tecnologías pagadas que incluso deben ser instaladas dentro de la empresa consumiendo recursos y en algunos casos subutilizándolos, los servicios del cloud computing poseen la flexibilidad y capacidad que la empresa requiere de acuerdo a sus necesidades de crecimiento y de cambio continuo que el mercado exige en la actualidad. Algunas empresas no invierten en dichas tecnologías porque no saben que pueden accederlas a costos bajos e incluso en algunos casos sin pagar un solo centavo y pierden competitividad y productividad por simple desconocimiento. El uso de servicios SaaS e IaaS afecta al flujo de caja de manera positiva comparada con una inversión en infraestructura propia, sobre todo en empresas que están empezando a funcionar o en aquellas que están en proceso de renovación tecnológica. Después de realizada esta investigación se recomienda el uso de los servicios de cloud computing, pero es evidente que no son útiles para todas las empresas y la utilidad depende de la criticidad de las aplicaciones o infraestructuras, el momento por el que pasa la compañía, tamaño de la empresa, ¿Cloud pública o Cloud privada?, en ocasiones, virtualizar también es racionalizar y la visión integral de la seguridad. Por otro lado, después de tabular los datos obtenidos en la encuesta número 2 se evidenció que el lanzamiento del Servicio en la nube de EcuFlow incrementó la demanda de esta herramienta en el mercado.

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Medical universities and teaching hospitals in Iraq are facing a lack of professional staff due to the ongoing violence that forces them to flee the country. The professionals are now distributed outside the country which reduces the chances for the staff and students to be physically in one place to continue the teaching and limits the efficiency of the consultations in hospitals. A survey was done among students and professional staff in Iraq to find the problems in the learning and clinical systems and how Information and Communication Technology could improve it. The survey has shown that 86% of the participants use the Internet as a learning resource and 25% for clinical purposes while less than 11% of them uses it for collaboration between different institutions. A web-based collaborative tool is proposed to improve the teaching and clinical system. The tool helps the users to collaborate remotely to increase the quality of the learning system as well as it can be used for remote medical consultation in hospitals.

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Although climate models have been improving in accuracy and efficiency over the past few decades, it now seems that these incremental improvements may be slowing. As tera/petascale computing becomes massively parallel, our legacy codes are less suitable, and even with the increased resolution that we are now beginning to use, these models cannot represent the multiscale nature of the climate system. This paper argues that it may be time to reconsider the use of adaptive mesh refinement for weather and climate forecasting in order to achieve good scaling and representation of the wide range of spatial scales in the atmosphere and ocean. Furthermore, the challenge of introducing living organisms and human responses into climate system models is only just beginning to be tackled. We do not yet have a clear framework in which to approach the problem, but it is likely to cover such a huge number of different scales and processes that radically different methods may have to be considered. The challenges of multiscale modelling and petascale computing provide an opportunity to consider a fresh approach to numerical modelling of the climate (or Earth) system, which takes advantage of the computational fluid dynamics developments in other fields and brings new perspectives on how to incorporate Earth system processes. This paper reviews some of the current issues in climate (and, by implication, Earth) system modelling, and asks the question whether a new generation of models is needed to tackle these problems.

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We present a general Multi-Agent System framework for distributed data mining based on a Peer-to-Peer model. Agent protocols are implemented through message-based asynchronous communication. The framework adopts a dynamic load balancing policy that is particularly suitable for irregular search algorithms. A modular design allows a separation of the general-purpose system protocols and software components from the specific data mining algorithm. The experimental evaluation has been carried out on a parallel frequent subgraph mining algorithm, which has shown good scalability performances.