Performance Analysis of the Multi-pass Transformation for Complex 3D-Stencils on GPUs

Artículo presentado al Congreso Español de Informática 2013Performance Analysis of the Multi-pass Transformation for Complex 3D-Stencils on GPU

Empleo del Análisis de Redes Sociales para el estudio de la estructura de la relación entre definiciones del concepto estrategia elaboradas entre los años 1962 y 2003

El presente trabajo se realizó con el objetivo de determinar la estructura de la relación entre las definiciones del concepto de estrategia abordadas por diferentes autores desde su surgimiento en la década del 60 del siglo XX. Para realizar el mismo se parte de la selección de 38 definiciones elaboradas por diferentes autores. Se realizó la deconstrucción de cada definición para escoger los términos claves empledos en cada una. Luego se elaboró una matriz de afiliación utilizando como unidad de observación cada autor y como variables los términos claves seleccionados de cada definición. Se asignó (1) a la presencia del témino en la definición y (0) a la ausencia del mismo. Mediante el empleo del programa Netdraw se obtuvo la estructura de las relaciones entre términos claves. Se empleó la prueba Kappa Cohen para determinar el coeficiente de concordancia entre cada par de autores que abordaron la definición del concepto estrategia, luego se construyó una matriz de incidencia, para lo cual se asumió que existe relación (1) si y sólo si existe un coeficiente de concordancia bueno (K>0.40) y no existe relación (0) si ocurre lo contrario (K0.40) and there is no relation (0) if the opposi occurs (K<0.40). Finally, the structure of relations among the authors was obtained through Net Draw

Efficient Floating-Point Representation for Balanced Codes for FPGA Devices

Trabajo premiado con Best paper AwardWe propose a floating–point representation to deal efficiently with arithmetic operations in codes with a balanced number of additions and multiplications for FPGA devices. The variable shift operation is very slow in these devices. We propose a format that reduces the variable shifter penalty. It is based on a radix–64 representation such that the number of the possible shifts is considerably reduced. Thus, the execution time of the floating–point addition is highly optimized when it is performed in an FPGA device, which compensates for the multiplication penalty when a high radix is used, as experimental results have shown. Consequently, the main problem of previous specific highradix FPGA designs (no speedup for codes with a balanced number of multiplications and additions) is overcome with our proposal. The inherent architecture supporting the new format works with greater bit precision than the corresponding single precision (SP) IEEE–754 standard.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. IEEE, IEEE Computer Societ

Tecnologías para el archivo de información digital a largo plazo

Las tecnologías digitales ha aumentado enormemente nuestra capacidad para almacenar cantidades ingentes de información. Hoy se guarda cualquier tipo de información en algún dispositivo digital. Pero esta capacidad de almacenamiento no se ha visto acompañada de un aumento de la longevidad

Speculative Barriers with Transactional Memory

Transactional Memory (TM) is a synchronization model for parallel programming which provides optimistic concurrency control. Transactions can run in parallel and are only serialized in case of conflict. In this work we use hardware TM (HTM) to implement an optimistic speculative barrier (SB) to replace the lock-based solution. SBs leverage HTM support to elide barriers speculatively. When a thread reaches an SB, a new SB transaction is started, keeping the updates private to the thread, and letting the HTM system detect potential conflicts. Once the last thread reaches the corresponding SB, the speculative threads can commit their changes. The main contributions of this work are: an API for SBs implemented with HTM extensions; a procedure to check the speculation state in between barriers to enable SBs with non-transactional codes; a HTM SB-aware conflict resolution enhancement where SB transactions stall on a conflict with a standard transaction; and a set of SB use guidelines derived from our experience on using SBs in a variety of applications. We evaluated our proposals in two different architectures with a full-system simulator and an IBM Power8 server. Results show an overall performance improvement of SBs over traditional barriers

In Vitro and In Situ Characterization of Fish Thymic Nurse Cells

We present an enzyme- and immuno-cytochemical, and ultrastructural characterization of trout thymic nurse cells (TNCs). Our data suggest that isolated trout thymic multicellular complexes are epithelial cells with acidic compartments that may be involved in the processing of antigens and in the generation of the MHC-II proteins that these cell express, and also that isolated TNCs are the In Vitro equivalent of the pale and intermediate electronlucent epithelial cells located in the inner zone of the trout thymus, constituting indirect evidence of the phylogenetical relationships of the inner zone of the teleost thymus with the thymic cortex of higher vertebrates

Comparing assembly strategies for third-generation sequencing technologies across different genomes

The recent advent of long-read sequencing technologies, such as Pacific Biosciences (PacBio) and Oxford Nanopore technology (ONT), has led to substantial accuracy and computational cost improvements. However, de novo whole-genome assembly still presents significant challenges related to the computational cost and the quality of the results. Accordingly, sequencing accuracy and throughput continue to improve, and many tools are constantly emerging. Therefore, selecting the correct sequencing platform, the proper sequencing depth and the assembly tools are necessary to perform high-quality assembly. This paper evaluates the primary assembly reconstruction from recent hybrid and non-hybrid pipelines on different genomes. We find that using PacBio high-fidelity long-read (HiFi) plays an essential role in haplotype construction with respect to ONT reads. However, we observe a substantial improvement in the correctness of the assembly from high-fidelity ONT datasets and combining it with HiFi or short-reads.Funding for open access charge: Universidad de Málaga / CBU

Barreras especulativas con memoria transaccional

La Memoria Transaccional (TM) es una alternativa al modelo de programación basado en locks que pretende simplificar la programación paralela. TM sustituye locks por transacciones para resolver el problema de la exclusión mutua. Las transacciones se ejecutan de manera optimista, en paralelo, mientras el sistema transaccional comprueba si hay conflictos entre ellas. En este trabajo proponemos el uso de transacciones para implementar una barrera especulativa (SB) optimista que reemplace las barreras pesimistas basadas en locks. SBs aprovecha el soporte TM hardware para permitir que los hilos salten la barrera y ejecuten especulativamente. Cuando un hilo llega a una barrera abre una transacción para proteger la ejecución y poder volver a la barrera en caso de conflicto. Cuando el último hilo alcanza la barrera los hilos especulativos pueden acometer los cambios.Sociedad de Arquitectura y Tecnología de Computadores (SARTECO) Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Learning modes in current contexts to improve the teaching process

Learning is a subject of constant concern for all those dedicated to this activity, where there are different paradigmatic approaches. The objective of this work is to assess the different types of learning associated with current contexts in order to improve the teaching-learning process. The fundamental methods used have been, from the theoretical, the logical historical and the synthetic analytic; and from empyrean, observation and analysis of documents. The main results are associated with the description of the most useful methods in these times, the psychological current that underlies each one of them, their complementary elements and adaptations (whether virtual or face-to-face) to the generation that today is in the classrooms. With the assessment of the different learning concepts, a tool has been provided to support the work of teachers of these timesEl aprendizaje es un tema de constate preocupación para todos los dedicados a esta actividad, donde existen diferentes enfoques paradigmáticos. El objetivo de este trabajo es valorar los diferentes tipos de aprendizaje asociados a los contextos actuales para la mejora del proceso de enseñanza aprendizaje. Los métodos fundamentales utilizados han sido, desde lo teórico, el histórico lógico y al analítico sintético; y desde la empírea, la observación y el análisis de documentos. Los principales resultados se asocian a la descripción de los métodos de mayor utilidad en estos tiempos, la corriente psicológica que subyace detrás de cada uno de ellos, sus elementos complementarios y adaptaciones (sean virtuales o presenciales) a la generación que hoy se encuentra en las aulas. Con la valoración de los diferentes conceptos de aprendizajes, se ha propiciado una herramienta de sustento al quehacer de los docentes de estos tiempo

KIR+ CD8+ T Lymphocytes in Cancer Immunosurveillance and Patient Survival: Gene Expression Profiling

Killer-cell immunoglobulin-like receptors (KIR) are molecules expressed by the most important cells of the immune system for cancer immune vigilance, natural killer (NK) and effector T cells. In this manuscript we study the role that cytotoxic CD8+ T cells expressing KIR receptors could play in cancer immune surveillance. With this objective, frequencies of different KIR+ CD8+ T cell subsets are correlated with the overall survival of patients with melanoma, ovarian and bladder carcinomas. In addition, the gene expression profile of KIR+ CD8+ T cell subsets related to the survival of patients is studied with the aim of discovering new therapeutic targets, so that the outcome of patients with cancer can be improved. Killer-cell immunoglobulin-like receptors (KIR) are expressed by natural killer (NK) and effector T cells. Although KIR+ T cells accumulate in oncologic patients, their role in cancer immune response remains elusive. This study explored the role of KIR+CD8+ T cells in cancer immunosurveillance by analyzing their frequency at diagnosis in the blood of 249 patients (80 melanomas, 80 bladder cancers, and 89 ovarian cancers), their relationship with overall survival (OS) of patients, and their gene expression profiles. KIR2DL1+ CD8+ T cells expanded in the presence of HLA-C2-ligands in patients who survived, but it did not in patients who died. In contrast, presence of HLA-C1-ligands was associated with dose-dependent expansions of KIR2DL2/S2+ CD8+ T cells and with shorter OS. KIR interactions with their specific ligands profoundly impacted CD8+ T cell expression profiles, involving multiple signaling pathways, effector functions, the secretome, and consequently, the cellular microenvironment, which could impact their cancer immunosurveillance capacities. KIR2DL1/S1+ CD8+ T cells showed a gene expression signature related to efficient tumor immunosurveillance, whereas KIR2DL2/L3/S2+CD8+ T cells showed transcriptomic profiles related to suppressive anti-tumor responses. These results could be the basis for the discovery of new therapeutic targets so that the outcome of patients with cancer can be improved