High Performance Java Remote Method Invocation for Parallel Computing on Clusters

This is a post-peer-review, pre-copyedit version. The final authenticated version is available online at: http://dx.doi.org/10.1109/ISCC.2007.4381536[Abstract] This paper presents a more efficient Java remote method invocation (RMI) implementation for high-speed clusters. The use of Java for parallel programming on clusters is limited by the lack of efficient communication middleware and high-speed cluster interconnect support. This implementation overcomes these limitations through a more efficient Java RMI protocol based on several basic assumptions on clusters. Moreover, the use of a high performance sockets library provides with direct high-speed interconnect support. The performance evaluation of this middleware on a gigabit Ethernet (GbE) and a scalable coherent interface (SCI) cluster shows experimental evidence of throughput increase. Moreover, qualitative aspects of the solution such as transparency to the user, interoperability with other systems and no need of source code modification can augment the performance of existing parallel Java codes and boost the development of new high performance Java RMI applications.Ministerio de Education y Ciencia; TIN2004-07797-C02Xunta de Galicia; PGIDIT06PXIB105228PR

Design and Implementation of MapReduce using the PGAS Programming Model with UPC

This is a post-peer-review, pre-copyedit version of an article published in International Conference on Parallel and Distributed Systems. Proceedings. The final authenticated version is available online at: http://dx.doi.org/10.1109/ICPADS.2011.162[Abstract] MapReduce is a powerful tool for processing large data sets used by many applications running in distributed environments. However, despite the increasing number of computationally intensive problems that require low-latency communications, the adoption of MapReduce in High Performance Computing (HPC) is still emerging. Here languages based on the Partitioned Global Address Space (PGAS) programming model have shown to be a good choice for implementing parallel applications, in order to take advantage of the increasing number of cores per node and the programmability benefits achieved by their global memory view, such as the transparent access to remote data. This paper presents the first PGAS-based MapReduce implementation that uses the Unified Parallel C (UPC) language, which (1) obtains programmability benefits in parallel programming, (2) offers advanced configuration options to define a customized load distribution for different codes, and (3) overcomes performance penalties and bottlenecks that have traditionally prevented the deployment of MapReduce applications in HPC. The performance evaluation of representative applications on shared and distributed memory environments assesses the scalability of the presented MapReduce framework, confirming its suitability.Ministerio de Ciencia e Innovación; TIN2010-1673

Parallel Brownian dynamics simulations with the message-passing and PGAS programming models

This is a post-peer-review, pre-copyedit version of an article published in Computer Physics Communications. The final authenticated version is available online at: https://doi.org/10.1016/j.cpc.2012.12.015[Abstract] The simulation of particle dynamics is among the most important mechanisms to study the behavior of molecules in a medium under specific conditions of temperature and density. Several models can be used to compute efficiently the forces that act on each particle, and also the interactions between them. This work presents the design and implementation of a parallel simulation code for the Brownian motion of particles in a fluid. Two different parallelization approaches have been followed: (1) using traditional distributed memory message-passing programming with MPI, and (2) using the Partitioned Global Address Space (PGAS) programming model, oriented towards hybrid shared/distributed memory systems, with the Unified Parallel C (UPC) language. Different techniques for domain decomposition and work distribution are analyzed in terms of efficiency and programmability, in order to select the most suitable strategy. Performance results on a supercomputer using up to 2048 cores are also presented for both MPI and UPC codes.Ministerio de Ciencia e Innovación ; TIN2010-16735Xunta de Galicia; ref. 2010/

Design and manufacture of a self-supporting racing motorcycle seat made on carbon fiber

Este trabajo presenta el diseño, cálculo y fabricación del colín de moto de competición, que ha participado en la edición MotoStudent 2016, celebrada en octubre de 2016 en el circuito de Alcañiz, representando a la Universidad de Málaga. En esta ocasión se presentaban dos motos, una dentro de la categoría Petrol (motor de 4 tiempos y 250 cc) y otra en la categoría Electric. Se trata de una estructura autoportante que sustituye a la utilización del subchasis y colín tradicionales, con el objetivo de que la solución sea más ligera que el conjunto anterior. Como material se ha seleccionado un tejido de carbono sarga 2x2 de 3K y 200 g/m2 y resina epoxi Resoltech 1070/1074. El proceso de fabricación seleccionado ha sido el moldeo manual y posterior compactado con bolsa de vacío. Mediante la utilización de modelos micromecánicos y a partir del porcentaje de fibra, se han estimado las propiedades de la lámina elemental de material compuesto. Dichas propiedades han sido implementadas en el programa de elementos finitos Patran-Nastran para la optimización de la pieza. Una vez diseñado el colín, se ha fabricado un modelo de la pieza a partir del mecanizado de placas de madera MDF que ha servido para fabricar el molde de la pieza en fibra de vidrio. Los colines diseñados fueron homologados por la organización de la competición. El colin desarrollado es un 50% más ligero que la solución actual. El molde fabricado permite la obtención de varias piezas con la consiguiente reducción de costes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Experimental.numerical correlation of a padel racket subject to impact

Los artículos deportivos son cada vez más sofisticados y requieren de soluciones de alta tecnología para la mejora de sus prestaciones. Un ejemplo de esto pueden ser las palas de pádel, que deben aunar características como ligereza, rigidez y durabilidad. La respuesta a estos requerimientos es una estructura multimaterial, formada por materiales compuestos, principalmente fibra de vidrio y carbono, resinas poliméricas y espumas de alta tecnología. Los fabricantes se enfrentan a multitud de variables durante la fase de diseño (forma, materiales, distribución de agujeros, …) que dotan a la pala de unas características propias y que no son capaces de evaluar hasta que los jugadores las prueban. Es en ese momento cuando, en función de las sensaciones de cada tipo de jugador, se valida la calidad de la pala y el perfil de jugador al que irá dirigida. Este procedimiento prueba-error supone un elevado coste material y alarga el periodo de desarrollo de un nuevo producto. El objetivo de este trabajo, desarrollado en colaboración con la empresa Shark Pádel S.L., es desarrollar un modelo de elementos finitos que permita definir parámetros ingenieriles del comportamiento de la pala, que traduzcan las sensaciones de los jugadores, para posteriormente poder evaluar su comportamiento al variar cualquiera de los parámetros de diseño.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Vineyard area estimation using medium spatial resolution satellite imagery

P. 441-452The European Union requires member states to estimate their wine growing potential. For this porpose, most member states have developed or updated vineyard registers. The present study suggests locating vineyards using medium spatial resolution satellite imagery. The work was carried out using Landsat images that were validated for the Designation of Origin "Bierzo", León, SpainS

Influcencia de la velocidad de aplicación de carga en la delaminación de materiales compuestos laminados

El impacto es una de las solicitaciones más críticas que actúa sobre una estructura, induciendo en el material importantes velocidades de deformación. En impactos transversales de baja velocidad sobre materiales compuestos laminados, la secuencia de degradación es la siguiente: fractura intralaminar de la matriz que no afecta a la capacidad portante pero que facilita la aparición del segundo modo de fallo, el fallo interlaminar de la matriz o delaminación y finalmente el fallo intralaminar de la fibra. La delaminación es uno de los mecanismos de fallo críticos de los materiales compuestos laminados, ya que supone una importante pérdida de capacidad portante, es difícil de detectar visualmente y su evolución condiciona el posterior fallo del componente. Dicho comportamiento depende de su tenacidad a fractura interlaminar. Actualmente, no existe un consenso respecto de la dependencia entre la tenacidad a fractura interlaminar, en modos I y II, y la velocidad de deformación. Sin embargo, ensayos de impacto biaxial equienergéticos permiten observar que el área delaminada aumenta con la velocidad de aplicación de carga, lo que indica una dependencia de la energía de fractura con respecto a la velocidad de aplicación de carga. En este trabajo se presenta la metodología puesta a punto, así como los resultados experimentales de un ensayo de modo I basado en la aplicación de carga mediante caída de dardo, pudiendo alcanzarse los 20 m/s.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Experimental numerical correlation of the delamination of composite structures subjected to low speed impact

In this work, we have analyzed the delamination caused by a low velocity impact on carbon-epoxy laminates made with balanced 0/90 braided fabrics and made by resin infusion. The items have been tested with a fall drop system. The numerical simulation was performed using the Explicit Non-Lineal Finite Element Method (NASTRAN SOL700). Delamination was analyzed using cohesive zone models (CZM). The parameters of the Tvergaard and Hutchinson constitutive law have been defined based on experimental fracture data of the laminate and mechanical properties of the resin used. The results show a good correlation (error<2%) regarding the maximum force, contact time and residual stiffness. The good correlation in evaluating the residual stiffness after impact has special interest since it allows the designer to evaluate the integrity level of a structure that has suffered an impact, generating damage.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Performance Evaluation of MPI, UPC and OpenMP on Multicore Architectures

This is a post-peer-review, pre-copyedit version of an article published in Lecture Notes in Computer Science. The final authenticated version is available online at: https://doi.org/10.1007/978-3-642-03770-2_24[Abstract] The current trend to multicore architectures underscores the need of parallelism. While new languages and alternatives for supporting more efficiently these systems are proposed, MPI faces this new challenge. Therefore, up-to-date performance evaluations of current options for programming multicore systems are needed. This paper evaluates MPI performance against Unified Parallel C (UPC) and OpenMP on multicore architectures. From the analysis of the results, it can be concluded that MPI is generally the best choice on multicore systems with both shared and hybrid shared/distributed memory, as it takes the highest advantage of data locality, the key factor for performance in these systems. Regarding UPC, although it exploits efficiently the data layout in memory, it suffers from remote shared memory accesses, whereas OpenMP usually lacks efficient data locality support and is restricted to shared memory systems, which limits its scalability.Gobierno de España; TIN2007-67537-C03-0

Performance Evaluation of Unified Parallel C Collective Communications

This is a post-peer-review, pre-copyedit version. The final authenticated version is available online at: http://dx.doi.org/10.1109/HPCC.2009.88[Abstract] Unified Parallel C (UPC) is an extension of ANSI C designed for parallel programming. UPC collective primitives, which are part of the UPC standard, increase programming productivity while reducing the communication overhead. This paper presents an up-to-date performance evaluation of two publicly available UPC collective implementations on three scenarios: shared, distributed, and hybrid shared/distributed memory architectures. The characterization of the throughput of collective primitives is useful for increasing performance through the runtime selection of the appropriate primitive implementation, which depends on the message size and the memory architecture, as well as to detect inefficient implementations. In fact, based on the analysis of the UPC collectives performance, we proposed some optimizations for the current UPC collective libraries. We have also compared the performance of the UPC collective primitives and their MPI counterparts, showing that there is room for improvement. Finally, this paper concludes with an analysis of the influence of the performance of the UPC collectives on a representative communication-intensive application, showing that their optimization is highly important for UPC scalability.Ministerio de Ciencia e Innovación; TIN2007-67537-C03-02Xunta de Galicia; 3/2006 DOGA 13/12/200