Enseñanza y Aprendizaje de Ingeniería de Computadores
y, más concretamente, los relatos de episodios de su desarrollo contribuyen a conformar los mapas... more y, más concretamente, los relatos de episodios de su desarrollo contribuyen a conformar los mapas conceptuales que permiten fijar los conceptos esenciales, y a motivar a los estudiantes en el estudio de dicha disciplina. Aquí se proponen algunos episodios relacionados con la evolución de los computadores para incluir en un curso de Arquitectura de Computadores, junto con referencias que permitan acceder a información relativa a los mismos.
Los electroencefalogramas son señales eléctricas compuestas por un número elevado de característi... more Los electroencefalogramas son señales eléctricas compuestas por un número elevado de características, por lo que el coste computacional de las tareas asociadas a esta disciplina es normalmente bastante alto. Una solución factible para este problema es el uso de metaheurísticas eficientes que proporcionen una solución adecuada para el problema en un tiempo razonable. Además, elegir un lenguaje de programación apropiado es vital ya que influirá en la eficiencia del procedimiento a implementar. A pesar de que los lenguajes de programación con una curva de aprendizaje baja como Python son muy utilizados, no son la mejor elección a la hora de lograr una gran eficiencia. En este contexto, usar lenguajes de más bajo nivel como C++ se torna en algo fundamental ya que permiten a los programadores aprovechar mejor todas las capacidades del hardware. Con esto en mente, este trabajo propone un procedimiento de selección de características multi-objetivo paralelo que ha sido implementado con C++...
2002 Kluwer Academic Publishers. Manufactured in The Netherlands. Parameter Configurations for Hole Extraction in Cellular Neural Networks (CNN)
Abstract. It is shown that the holes of the objects in an input image with a CT-CNN [1] or a DT-C... more Abstract. It is shown that the holes of the objects in an input image with a CT-CNN [1] or a DT-CNN [2] may be obtained in a single transient using just one linear parameter configuration. A set of local rules is given that describe how a CNN with a linear configuration may extract the hole of the objects of an input image in a single transient. The parameter configuration for DT-CNNs or for CT-CNNs is obtained as the solution of a single linear programming problem, including robustness as an objective. The tolerances to multiplicative and additive errors caused by circuit inaccuracies for the linear hole-extraction configurations proposed have been deduced. These tolerable errors have been corroborated by simulations. The tolerance to errors and the speed of the CT-CNN linear configuration proposed for hole extraction are compared with those of the CT-CNN nonlinear configuration found in the bibliography [3]. Key Words: cellular neural networks, hole extraction, tolerance to errors...
It has been several academic years since the beginning of study programmes at the University of G... more It has been several academic years since the beginning of study programmes at the University of Granada according to the guidelines of the European Higher Education Area. In this paper, after summarizing the main objectives of the so-called Bologna reform, some of the consequences of its implementation in Spain are described. Moreover, the subject of Computer Architecture, taught in the second course by some of the authors of the paper, is considered as a reference to extract some of the conclusions of the paper.
It is usual that the applications executed in data centers require the distribution of the same d... more It is usual that the applications executed in data centers require the distribution of the same data from one node to others at various execution points and that some of them require to cope with multiple of these diffusions in parallel. Multicastbased communications are an alternative solution to sending data efficiently to multiple nodes. This paper proposes a novel technique which offers reliability and congestion control in the multi-multicast transfers in data center networks. The proposal is based on: (1) a new congestion control mechanism, which monitors the control information of the receivers, reducing the server injection rate, (2) taking advantage of the switch diffusion hardware, and (3) using IGMP snooping, which allows a network switch to multicast a packet just to the output links with host receivers joined to a multicast group. The implementation is made at user level and uses the UDP interface. Evaluation tests are performed in a CentOS-based cluster composed of 12 servers in the presence of multiple diffusions at the same time. Test results show improvements in the global bandwidth, avoid network saturation, and reduce overhead included by unicast communications in data transmission.
Multifactor authentication is a relevant tool in securing IT infrastructures combining two or mor... more Multifactor authentication is a relevant tool in securing IT infrastructures combining two or more credentials. We can find smartcards and hardware tokens to leverage the authentication process, but they have some limitations. Users connect these devices in the client node to log in or request access to services. Alternatively, if an application wants to use these resources, the code has to be amended with bespoke solutions to provide access. Thanks to advances in system-on-chip devices, we can integrate cryptographically robust, low-cost solutions. In this work, we present an autonomous device that allows multifactor authentication in client–server systems in a transparent way, which facilitates its integration in High-Performance Computing (HPC) and cloud systems, through a generic gateway. The proposed electronic token (eToken), based on the system-on-chip ESP32, provides an extra layer of security based on elliptic curve cryptography. Secure communications between elements use M...
Protein structure prediction (PSP) is an open problem with many useful applications in discipline... more Protein structure prediction (PSP) is an open problem with many useful applications in disciplines such as Medicine, Biology and Biochemistry. As this problem presents a vast search space where the analysis of each protein structure requires a significant amount of computing time, it is necessary to propose efficient search procedures in this very large space of possible protein conformations. Thus, an important issue is to add vital information (such as rotamers) to the process to decrease its active search space-rotamers give statistical information about torsional angles and conformations. In this paper, we propose a new method to refine the torsional angles of a protein to remake/reconstruct its structures with more resemblance to its original structure. This approach could be used to improve the accuracy of the rotamer libraries and/or to extract information from the Protein Data Bank to facilitate solution of the PSP problem.
Los usuarios de Entornos de Computación Científica (SCE, por sus siglas en inglés) siempre requie... more Los usuarios de Entornos de Computación Científica (SCE, por sus siglas en inglés) siempre requieren mayor potencia de cálculo para sus aplicaciones. Utilizando las herramientas propuestas, los usuarios de las conocidas plataformas Matlab ® y Octave, en un cluster de computadores, pueden paralelizar sus aplicaciones interpretadas utilizando paso de mensajes, como el proporcionado por PVM (Parallel Virtual Machine) o MPI (Message Passing Interface). Para muchas aplicaciones SCE es posible encontrar un esquema de paralelización con ganancia en velocidad casi lineal. Estas herramientas son interfaces prácticamente exhaustivas a las correspondientes librerías, soportan todos los tipos de datos compatibles en el SCE base y se han diseñado teniendo en cuenta el rendimiento y la facilidad de mantenimiento. En este artículo se resumen trabajos anteriores, su repercusión, y algunos resultados obtenidos por usuarios finales. Con base en la herramienta más reciente, la Toolbox MPI para Octave, se describen brevemente sus características principales, y se presenta un estudio de caso, el conjunto de Mandelbrot. Palabras clave Computación científica, programación paralela, computación de altas prestaciones, computación cluster, paso de mensajes, Matlab paralelo. Artículo de Revisión-Fecha de recepción: 14 de septiembre de 2012-Fecha de aceptación: 1 de octubre de 2012 1 Este trabajo ha sido financiado por el proyecto español ARC-VISION (MICINN TEC2010-15396) y el proyecto europeo TOMSY (FP7-ICT-2009-6-270436).
It is shown that the holes of the objects in an input image with a CT-CNN [1] or a DT-CNN [2] may... more It is shown that the holes of the objects in an input image with a CT-CNN [1] or a DT-CNN [2] may be obtained in a single transient using just one linear parameter configuration. A set of local rules is given that describe how a CNN with a linear configuration may extract the hole of the objects of an input image in a single transient. The parameter configuration for DT-CNNs or for CT-CNNs is obtained as the solution of a single linear programming problem, including robustness as an objective. The tolerances to multiplicative and additive errors caused by circuit inaccuracies for the linear hole-extraction configurations proposed have been deduced. These tolerable errors have been corroborated by simulations. The tolerance to errors and the speed of the CT-CNN linear configuration proposed for hole extraction are compared with those of the CT-CNN nonlinear configuration found in the bibliography [3].
This paper deals with the obtention of robust parameter configurations for DT-CNNs and for a clas... more This paper deals with the obtention of robust parameter configurations for DT-CNNs and for a class of CT-CNNs (here called CT-CNNs with Discrete Configurations, DC-CT-CNN), in the presence of additive and multiplicative implementation errors. Expressions that characterize the tolerance to both multiplicative and additive errors caused by circuit inaccuracies in DT-CNNs and DC-CT-CNNs VLSI implementation are first deduced. Taking into account those expressions it is proposed to obtain robust parameter configurations, by using a design process based on local rules, as the solution of a single linear programming problem. The process is applied to the generation of robust configuration for some tasks. The tolerance to errors of these configurations has been corroborated by simulations. The differences in parameter values and tolerance to errors, between the robust configuration obtained for solving a particular task in DT-CNNs and that obtained in DC-CT-CNNs, are given. 1.-INTRODUCTION The Cellular Neural Network model proposed by L. O. Chua and L. Yang [1] has been widely used for image processing tasks [2]. The time evolution of the state of a cell (neuron or pixel) c in an NxM-cell CNN is described by the differential equation [1]: where n denotes a generic cell belonging to the neighbourhood of cell c, N R (c), with radius equal to R (for example, N 1 (c) is the set of 3x3 cells centred on c, N 1 (c)={ c-N-1, c-N, c-N+1, c-1, c, c+1, c+N-1, c+N, c+N+1}). x c is the state of cell c, y n and u n are the output and the input, respectively, of the cell n, I is an offset term, and the matrices A and B are called feedback and control templates respectively. Some authors have proposed [3] a discrete-time (DT) version of CNN obtained by applying the Euler integration algorithm to discretise the cell state equation. The state of a cell c in an NxM-cell DT-CNN is described
Resumen. En este trabajo se pone de manifiesto el interés de un perfil de Ingeniería de Computado... more Resumen. En este trabajo se pone de manifiesto el interés de un perfil de Ingeniería de Computadores a pesar de las características de nuestro entorno socio-económico. Además, se proponen preguntas relacionadas con la Estructura y Arquitectura del Computador, que son útiles y pertinentes para los distintos perfiles de grado en Ingeniería Informática. Por tanto, se argumenta a favor de una enseñanza de la Estructura y la Arquitectura de los Computadores centrada en los aspectos que ponen de manifiesto la interrelación de los distintos niveles de descripción del computador. Esta perspectiva permite motivar a estudiantes menos interesados en aspectos relacionados con los niveles tradicionalmente hardware.
En el marco de un Proyecto de Innovación Docente de la Universidad de Granada, aplicado a la asig... more En el marco de un Proyecto de Innovación Docente de la Universidad de Granada, aplicado a la asignatura de 5º curso “Arquitectura de Computadores II” (ACII) en el curso 2008-09, realizamos el diseño, compra, montaje, instalación y utilización de un mini-cluster de computadores orientado a aplicaciones científicas. En el curso 2009-10, disponiendo ya del equipo montado, la actividad se ha replanteado como instalación y utilización del cluster, habiéndose concurrido al Programa de Apoyo a Docencia Práctica para la adquisición de hardware adicional con el cual explotar las prestaciones del cluster (discos adicionales para servidor de disco, infraestructura Infiniband, etc). Esta contribución describe el método aplicado para desarrollar y evaluar la actividad, el cluster diseñado por los estudiantes y su configuración software, así como los resultados de encuestas de opinión de los estudiantes que participaron, posibles variaciones de la experiencia que podrían probarse, y las conclusio...
Scalable parallel implementation for 3D semi-implicit hydrodynamic models of shallow waters
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