Improving edge finite element assembly for geophysical electromagnetic modelling on shared-memory architectures

This work presents a set of node-level optimizations to perform the assembly of edge finite element matrices that arise in 3D geophysical electromagnetic modelling on shared-memory architectures. Firstly, we describe the traditional and sequential assembly approach. Secondly, we depict our vectorized and shared-memory strategy which does not require any low level instructions because it is based on an interpreted programming language, namely, Python. As a result, we obtained a simple parallel-vectorized algorithm whose runtime performance is considerably better than sequential version. The set of optimizations have been included to the work-flow of the Parallel Edge-based Tool for Geophysical Electromagnetic Modelling (PETGEM) which is developed as open-source at the Barcelona Supercomputing Center. Finally, we present numerical results for a set of tests in order to illustrate the performance of our strategy.This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 644202. The research leading to these results has received funding from the European Union's Horizon 2020 Programme (2014-2020) and from Brazilian Ministry of Science, Technology and Innovation through Rede Nacional de Pesquisa (RNP) under the HPC4E Project (www.hpc4e.eu), grant agreement No. 689772. Authors gratefully acknowledge the support from the Mexican National Council for Science and Technology (CONACYT). All numerical tests were performed on the MareNostrum supercomputer of the Barcelona Supercomputing Center - Centro Nacional de Supercomputación (www.bsc.es).Peer ReviewedPostprint (author's final draft

Experiences of foreign nurses in Finland : barriers

The field of nursing has seen a rising demand in the past decades. Nursing immigration and migration over the decades has been phenomenal. There is increased number of nurses emigrating from developing countries to developed countries in search of better working environments, better working motivations, better skills and so fort (Tregunno et al 2009). The research is contracted by KYKY. The KYKY project was developed by Salo region adult education center and Turku University of applied science. KYKY stands for Kansainvälistyvät työyhteisöt osaaviksi ja kilpailukykyisiksi, which translates as (International work community to be competent and competitive). The objective of the project is to help sustain and retain international qualified skilled and competitive workers for example in the social and healthcare field in Salo. Southwest Finland Centre for Economic Development, the European Social Fund (ESR), Turku University of Applied sciences and Salo region adult education center funds the project. The aim of the research is to find the experiences of foreign nurses in Finland. The purpose is to create a piece of work that will be available to future aspirant of nursing education in Finland, workers, teachers and all interested. The results indicates that Foreign nurses experience cultural discrimination, language, and communication barriers amongs many others

Strategies to parallelize a finite element mesh truncation technique on multi-core and many-core architectures

Achieving maximum parallel performance on multi-core CPUs and many-core GPUs is a challenging task depending on multiple factors. These include, for example, the number and granularity of the computations or the use of the memories of the devices. In this paper, we assess those factors by evaluating and comparing different parallelizations of the same problem on a multiprocessor containing a CPU with 40 cores and four P100 GPUs with Pascal architecture. We use, as study case, the convolutional operation behind a non-standard finite element mesh truncation technique in the context of open region electromagnetic wave propagation problems. A total of six parallel algorithms implemented using OpenMP and CUDA have been used to carry out the comparison by leveraging the same levels of parallelism on both types of platforms. Three of the algorithms are presented for the first time in this paper, including a multi-GPU method, and two others are improved versions of algorithms previously developed by some of the authors. This paper presents a thorough experimental evaluation of the parallel algorithms on a radar cross-sectional prediction problem. Results show that performance obtained on the GPU clearly overcomes those obtained in the CPU, much more so if we use multiple GPUs to distribute both data and computations. Accelerations close to 30 have been obtained on the CPU, while with the multi-GPU version accelerations larger than 250 have been achieved.Funding for open access charge: CRUE-Universitat Jaume

Inverse Problems in Lubrication Theory

Lubrication is the process whereby a fluid (the lubricant) fills the gap between two surfaces in close proximity and relative motion. Lubrication is employed to reduce friction and avoid contac

Uso de energía solar para la cocción de pan sustituido parcialmente por harina de quinoa (Chenopodium Quinoa Wild.)

Objetivos: 1) Estudiar las condiciones de funcionamiento de dos hornos solares: tipo caja y tipo tambor; 2) Evaluar la cocción de panes elaborados con harina de quinoa y 3) Estudiar la respuesta del consumidor en su aceptabilidad. Los panes con 0, 10, 15 y 20% de sustitución se hornearon y se midió radiación (W/m2 ), temperatura ambiente (°C) y temperatura interna del pan durante la cocción. Se realizaron pruebas de aceptabilidad con 112 consumidores. La hora local en que se alcanza la máxima temperatura interna del pan (tT°max), la velocidad de aumento de ésta (Va), el tiempo de duración de la cocción (Tdur) y el área bajo la curva (ABC) fueron las variables más afectadas por las condiciones de radiación y temperatura ambiente. El tipo de horno y el porcentaje de sustitución no fueron significativos en la aceptabilidad. Se observó una tendencia a valorar más el pan con 10% de quinoa.Aims: 1) to study the behavior of the working conditions of box type and drum solar cookers; 2) evaluate the cooking process of breads with quinoa flour and 3) study the consumer’s acceptability response. Four formulations were established with 0, 10, 15 and 20% of wheat flour substitution, and they were cooked into the cookers. Cookers working conditions–radiation (W/m2 ) and environment temperature (°C)- and internal temperature of the breads were measured during cooking process. Sensory acceptability tests were performed with 112 consumers. The cooking variables mostly affected by daily conditions of radiation and environment temperature were: local time at which the maximum temperature (tT°max) of breads was reached, rate of increase (Va), duration time (tdur) and area under the curve (ABC). The cooker type and % of quinoa were not significant on the sensory acceptability; therefore it was observed a tendency to prefer the bread with 10% of quinoa.Fil: Passamai, Victor Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones en Energía no Convencional; Argentina. Universidad Nacional de Salta. Facultad de Cs.exactas. Departamento de Fisica; ArgentinaFil: Armada, M.. Universidad Nacional de Salta. Consejo de Investigacion; Argentina. Universidad Nacional de Salta. Facultad de Ingenieria; ArgentinaFil: del Castillo, V.. Universidad Nacional de Salta. Consejo de Investigacion; ArgentinaFil: Goldner, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación para la Industria Química (i); Argentina. Universidad Nacional de Salta; Argentin

Finite difference modelling of rupture propagation with strong velocity-weakening friction

We incorporate rate- and state-dependent friction in explicit finite difference (FD) simulations of mode II dynamic ruptures in elastic media, using the Mimetic Operators Split-Node (MOSN) method, with adjustable order of spatial accuracy (second-, fourth- or mixed-order accurate), including an option that is fourth-order accurate at the fault discontinuity as well as in the elastic volume. At fault points, the rate and state equations combined with the spatially discretized momentum conservation equations form a coupled system of ordinary differential equations (ODEs) for slip velocity and state variable. As a consequence of the rapid damping of velocity perturbations due to the direct effect, this system exhibits numerical stiffness that is inversely proportional to velocity squared. Approximate solutions to this velocity-state system are achieved by two different implicit schemes: (i) a fourth-order Rosenbrock integration of the full system using multiple substeps and (ii) low order integrations (backward Euler and trapezoidal) of the velocity equation, time-staggered with analytic integration of the state equation under the approximation of constant slip velocity over the time step. In assessing the numerical schemes, we use three test problems: ruptures with frictional resistance controlled by (i) a slip evolution law with strong velocity-weakening behaviour at high slip rates, representing thermal weakening due to flash heating of microscopic asperity contacts, (ii) the classic (low-velocity) slip evolution law and (iii) the classic aging evolution law. A convergence analysis is carried out using reference solutions from a spectral boundary integral equation method (BIEM) (a method restricted to homogeneous media, with nominal spectral accuracy in space and second-order accuracy in time for smooth solutions). Errors are measured by root-mean-square differences of fault-plane time histories (slip, slip rate, traction and state). MOSN shows essentially the same convergence rates as BIEM: second-order convergence for slip and state-variable misfits, with slower (but at least first-order) convergence for slip rates and tractions. For a given grid spacing, fourth-order MOSN is as accurate as BIEM for all variables except slip-rate. MOSN-Rosenbrock nominally has fourth-order temporal accuracy for the fault-plane velocity-state ODE integration (compared to lower-order accuracy for the other two MOSN schemes) and therefore provides an important theoretical benchmark. However, it is sensitive to details of the elastic calculation scheme and occasionally its adaptive substepping performs poorly, leading to large excursions from the reference solution. In contrast, MOSN-trapezoidal is robust and reliable, much easier to implement than MOSN-Rosenbrock, and in all cases achieves precision as good as the latter without recourse to substepping. MOSN-Euler has the same advantages as MOSN-trapezoidal, except that its nominal first-order temporal accuracy ultimately leads to larger errors in slip and state variable compared with the higher-order MOSN schemes at sufficiently small grid spacings and time step

Facilitando el aprendizaje de la Arquitectura del Juego de Instrucciones

En este artículo se presenta la metodología y estrategias llevadas a cabo para la enseñanza de la Arquitectura del Juego de Instrucciones en la asignatura de Estructura de Ordenadores de 2º curso de Ingeniería Informática y en particular dentro del desarrollo de sus prácticas. Éstas están dedicadas a la introducción del lenguaje ensamblador de un procesador de propósito general. La metodología utilizada tiene en cuenta, entre otros aspectos, la elección del tipo de procesador y la herramienta de trabajo, la personalización del ritmo de trabajo y la responsabilidad del alumno en la consecución de los objetivos como ejes fundamentales del aprendizaje. Así, se pretende conseguir un acercamiento mucho menos traumático del alumno a una de las asignaturas que mayor importancia tiene en la formación de base de los futuros ingenieros informáticos. Los resultados obtenidos hasta el momento nos indican que la acogida por parte del alumno es positiva, quedando ésta reflejada en la facilidad e interés con que resuelven los problemas propuestos en cada práctica. Por ello se produce una mejora en el aprendizaje de la asignatura, aspecto que queda reflejado en la evaluación de su rendimiento