Manuel Sánchez

Mathematical Background and Attitudes toward Statistics in a Sample of Spanish College Students

To examine the relation of mathematical background and initial attitudes toward statistics of Spanish “college students in social sciences the Survey of Attitudes Toward Statistics was given to 827 students. Multivariate analyses tested the effects of two indicators of mathematical background (amount of exposure and achievement in previous courses) on the four subscales. Analysis suggested grades in previous courses are more related to initial attitudes toward statistics than the number of mathematics courses taken. Mathematical background was related with students affective responses to statistics but not with their valuing of statistics. Implications of possible research are discussed.

Trastornos electrocardiográficos y ecocardiográficos en niños con sobrepeso y obesidad

Fundamento y objetivo La obesidad esta asociada con factores de riesgo cardiovascular y fallo cardiaco. Sujetos y metodo Se comparo a 30 ninos que presentaban sobrepeso u obesidad con 30 ninos sanos. Se midieron los intervalos QT corregido (QTc), dispersion del QT (QTd), masa del ventriculo izquierdo, indice de masa del ventriculo izquierdo, fraccion de eyeccion y fraccion de acortamiento. Resultados Los intervalos QTc y QTd, masa del ventriculo izquierdo e indice de masa del ventriculo izquierdo fueron significativamente mayores en los ninos con sobrepeso u obesidad que en los controles. Conclusiones Los ninos con sobrepeso u obesidad tienen un incremento de los intervalos QTc, QTd, del volumen y masa del ventriculo izquierdo, y un mayor riesgo de arritmias que los controles. Estos resultados hacen considerar la necesidad de una especial monitorizacion cardiaca de los ninos obesos, en especial de los que tienen formas graves.

An access control system for multimedia content distribution

Multimedia content distribution has appeared as a new growth market offered by network providers, defining resource access infrastructures able to support both wired and wireless accesses. Although these infrastructures have been widely studied in the last years, the main aim of those works has been focused more on the distribution process than on a suitable security infrastructure to protect that content. Therefore, the study of security systems able to offer authentication, authorization and other security-related requirements for those kinds of scenarios is still an open research field. In this paper, we propose a new scheme which takes advantage of a previously existing underlying authorization infrastructure among the involved organizations, the NAS-SAML system, to build a multimedia content distribution with an advanced and extensible authorization mechanism. The target scenario is the one proposed by the VIDIOS project, which defines an architecture for multimedia transmissions across error prone networks such as Internet backbones and mobile access networks.

Análisis de respuestas abiertas en un cuestionario sobre conductas relacionadas con el SIDA

Resumen El objetivo de este trabajo es, por un lado, analizar y describir las respuestas que 402 alumnos de la Universidad de Huelva dan a una pregunta abierta—a través de análisis de textos—y, por otro, ver en quémedida estas respuestas se relacionan—por el método de las especificidades—con algunas características de los sujetos. Dichas características fueron determinadas a partir de sus respuestas en un cuestionario creado para medir conocimientos, actitudes, norma social percibida y control conductual percibido respecto a una conducta de prevención del SIDA: uso del condón. Los resultados del análisis de textos muestran cómo los sujetos justifican el no uso de condón en base a la estabilidad de sus relaciones sentimentales; además, los autores descubren que el cuestionario tiene efectos no previstos inicialmente por los investigadores sobre los sujetos estudiados: aporta nuevos concocimientos a los alumnos y les lleva a reflexionar sobre—e intentar cambiar—sus conductas de riesgo respecto al SIDA, entre otras consideraciones.

ROS Methodology to Work with Non-ROS Mobile Robots: Experimental Uses in Mobile Robotics Teaching

This paper presents a robotics platform for experimental and teaching purposes that allows control and remote access by using plain sockets (regular TCP/IP sockets) and websockets respectively. The system has been built from ROS middleware (Robot Operating System) and is capable of controlling multiple user operations. The robot hardware connected to sensors or/and actuators does not support ROS due to its features. This article focus attention on describing a work methodology to establish communication of the non-ROS robotic platforms and ROS.

GEO Fleet Operations with a Multi-Mission Satellite Control Center

HISPASAT Group is operating now four Satellites:1C, 1D, and SPAINSAT (to cover the demand of governmental services for the Spanish Ministry of Defense) in 30o West and Amazonas-1 in 61o West. In preparation to cover the emerging demand in 61o West, HISPASAT has under construction Amazonas-2 satellite, to be placed in 61o West along year 2009. Additional satellites are under study for both orbital positions in the plan to increase the available on orbit capacity. HISPASAT manages the Satellite Control Operations for Telemetry and Telecommand functions by using platform specific Satellite Control Centers (SCC), therefore having at the present stage three different SCC platfomrs. This approach is being revisited and HISPASAT’s philosophy is now oriented towards a more flexible and easy to operate concept that implies to integrate the satellite operations using a common control platform. That continues the trend already initiated with the Flight Dynamics with GMV’s focusGEO and will be complemented in the Satellite Control Center area with GMV’s hifly®.

Optimization of master-slave flip-flops for high-performance applications

The design of high-performance master-slave flip-flops is of crucial importance in modern VLSI. The optimization of existing structures is necessary when the requirements of the flip-flop is for low-power, high-speed or low-noise applications. In this work, the optimization via transistor sizing of a well-known master-slave flip-flop is investigated. A detailed analysis of the flip-flop structure provides information useful for optimization, giving an optimum solution for an specific high-performance application.

Synthesis of hybrid CBL/CMOS cell using multiobjective evolutionary algorithms

In this work, the optimization of circuits design by using multiobjective evolutionary algorithm is addressed. This methodology enable to deal with circuit specifications -formulated as objective functions- that can be conflicting and want to be optimize at the same time. After the optimization process, a set of different trade-off solutions for the design of the circuit is obtained. This way, SPEA (Strength Pareto Evolutionary Algorithm) has been tested as optimizer of an hybrid CBL/CMOS configurable cell. As a result, some conclusions about the optimized values of the transistor sizes of this cell in order to minimized some power comsumption and delay timing specifications are obtained.

A service-based architecture for integrating globus 2 and globus 3

During the past few years, Grid Computing has matured in terms of programming models and available tools. Some tools like the Globus Toolkit version 2 (GT2) are used in many international high performance distributed computing projects. Recently, the OGSA standard (Open Grid Services Architecture) has been defined, proposing a radically new philosophy compared to that of GT2. Analyzing the evolution of the scientific community working on Grid Computing, we foresee a progressive shift of current developments to this new standard, that already has a reference implementation: GT3. This paper describes the analysis and design of an architecture of OGSA Grid Services that aims to integrate both platforms seamlessly, allowing remote job invocation from GT3 to GT2 holding all the security properties, and transparent for the user.

Interacciones educativas de una madre con sus dos hijos gemelos. El papel de la deficiencia auditiva leve

Resumen El presente artículo tiene por objeto examinar, a través de análisis descriptivos y secuenciales, las interacciones educativas de una madre con sus dos hijos gemelos en tres tareas diferentes: la construcción de un puzzle, la lectura de libros y la interacción verbal en torno al material de los puzzles. Uno de los hijos tiene una audición normal y el otro presenta una deficiencia auditiva leve (umbral de audición situado en los 30 dB). Los resultados muestran que la madre prestó más atención al hijo con deficiencia auditiva y estimuló su desarrollo de una forma más apropiada. Estos resultados son discutidos en relación a sus implicaciones para la crianza de gemelos y de hijos con pérdidas auditivas leves.