The impact of learning styles on student grouping for collaborative learning: a case study

The final publication is available at Springer via http://dx.doi.org/10.1007/s11257-006-9012-7Learning style models constitute a valuable tool for improving individual learning by the use of adaptation techniques based on them. In this paper, we present how the benefit of considering learning styles with adaptation purposes, as part of the user model, can be extended to the context of collaborative learning as a key feature for group formation. We explore the effects that the combination of students with different learning styles in specific groups may have in the final results of the tasks accomplished by them collaboratively. With this aim, a case study with 166 students of computer science has been carried out, from which conclusions are drawn. We also describe how an existing web-based system can take advantage of learning style information in order to form more productive groups. Our ongoing work concerning the automatic extraction of grouping rules starting from data about previous interactions within the system is also outlined. Finally, we present our challenges, related to the continuous improvement of collaboration by the use and dynamic modification of automatic grouping rules.This project has been funded by the Spanish Ministry of Science and Education, TIN2004-03140

Procesado mediante fusión zonal asistida con láser y caracterización de ánodos de níquel-circonia sobre sustratos de circonia

El presente proyecto tiene por objetivo mejorar la estabilidad eléctrica y microestructural de los cermets (compuestos cerámico-metálicos) de Ni-YSZ usados típicamente como ánodos en pilas de combustible de óxido sólido (SOFC). La mejora propuesta está basada en la solidificación direccional de eutécticos mediante la fusión asistida por láser. Este cambio en la microestructura aportará estabilidad a altas temperaturas y mejorará las prestaciones eléctricas del ánodo. Se ha demostrado previamente que los cermets de Ni-YSZ producidos a partir de mezclas eutécticas por fusión zonal asistida con láser, presentan propiedades microestructurales y eléctricas muy ventajosas en comparación con los cermets convencionales. Sin embargo, la integración de los ánodos procesados con láser en la pila de combustible es bastante compleja. En este proyecto, se pretende realizar la integración de dichos ánodos directamente sobre electrolitos de YSZ. En primer lugar se fabricarán sustratos de YSZ que posteriormente harán las funciones del electrolito de la celda. A continuación se elaborará una suspensión cerámica de NiO-YSZ para recubrir dicho electrolito. Es importante la caracterización reológica de esta pasta porque de ella dependerá la buena adherencia al sustrato, y que se obtenga además un espesor de capa suficiente para ser procesado. Por último se llevará a cabo la integración ánodo-electrolito mediante la técnica de dip coating. Posteriormente se realizará un estudio del procesado plano asistido por láser de las muestras, en función tanto de la potencia suministrada en el proceso como de la velocidad de avance de barrido. Por último se realizará una caracterización microestructural de los recubrimientos procesados mediante microscopía electrónica de barrido, que permita seleccionar las condiciones próximas a las óptimas. Con los parámetros de procesado seleccionados se fabricarán celdas simétricas (estructura ánodo-electrolito-ánodo). Se reducirá el óxido de níquel a níquel metálico en los ánodos para que aporte la conducción eléctrica y por último se realizará su caracterización eléctrica mediante espectroscopia de impedancias. El objetivo es estudiar la resistencia de polarización que aportan los ánodos a la resistencia total de la celda. Una vez obtenidos todos los resultados se compararán los datos de ánodos eutécticos con los cerámicos (fabricación convencional)

Network assisted content protection architectures for a connected world

Content protection is a key component for the success of a multimedia services platform, as proven by the plethora of solutions currently on the market. In this paper we analyze a new network scenario where permanent bidirectional connectivity and video-aware encryption technologies allow a trustful operation of ubiquitous end devices. We propose new scalable models for a content protection architecture that may achieve dramatic improvement in robustness, reliability, and scalability. Selective ciphering and countermeasures are included in those models, together with several examples of their application

Realización de tratamientos láser para el control de propiedades de multicapas de materiales funcionales

En la actualidad, la tecnología láser está en continuo desarrollo y es de gran interés en el campo del procesado de materiales, con tratamientos que consiguen propiedades extraordinariamente útiles en numerosos campos de aplicación. Paralelamente, en el campo de los materiales superconductores, una gran cantidad de estudios se están centrando en el desarrollo de bobinas superconductoras capaces de generar campos magnéticos muy elevados que pueden ser utilizados en un abanico amplio de aplicaciones industriales.<br /

Implementation of a High Measurement Rate VLP System

redOptical positioning systems have raised interest in recent years, due to the centimeter accuracy in three-dimension environments they are able to provide, thanks to the use of light emitting diodes (LED) and diode photoreceptors. This work is based on the design and implementation of the signal processing algorithms for an optical indoor positioning system. It is configured using some LED beacons placed at known positions and the corresponding receivers to be positioned moving in the coverage area. The definition and design of the hardware architecture for the processing associated to the receiver, for the case of a Quadrant Photodiode Angular Diversity Aperture (QADA) detector is proposed, analyzing different aspects involved in the final performance, such as the fixed-point notation used in the hardware definition. Furthermore, the implementation of the proposal includes an analog conditioning stage, an acquisition system, as well as a FPGA-based (Field-Programmable Gate Array) System-on-Chip (SoC) for implementing the necessary hardware and software elements, required to estimate the final position coordinates of the QADA receiver. In addition to the description of the positioning system and all its stages, some preliminary experimental tests are also shown, including position estimation for two specific locations, achieving the validation of a processing system associated with indoor positioning systems capable of handling high data rates (in the range of Msps)

High-rate acquisition system for an infrared LPS

2023 38th Conference on Design of Circuits and Integrated Systems (DCIS), 15-17 November 2023, Málaga, Spain.In the last years, the demand for positioning systems based on visible light, infrared light or, in general, optical signals has increased considerably due to their high accuracy and low cost compared to positioning systems based on other technologies, as well as their ease of integration due to their wide presence in domestic and industrial environments. The main constraint of these solutions is that the high speed of light makes the acquisition process complex. This work proposes a complete acquisition architecture for the twelve signals coming from four QADA (Quadrature Angular Diversity Aperture) photoreceptors, based on an analog front-end for signal conditioning at the input, an analog-to-digital converter, and a final digital stage using an FPGA for the acquisition of the data coming from the converter with high data rates up to 16.25 Msps. To verify the system performance, LS (Loosely Synchronized) sequences, often used in positioning systems, are emitted by a LED, and, later, they are acquired and digitally processed successfully by the proposed architecture in some preliminary experimental tests.Agencia Estatal de InvestigaciónUniversidad de AlcaláJunta de Comunidades de Castilla-La ManchaEuropean Science Foundatio

PREDIRCAM eHealth platform for individualized telemedical assistance for lifestyle modification in the treatment of obesity, diabetes, and cardiometabolic risk prevention: a pilot study (PREDIRCAM 1)

Background: Healthy diet and regular physical activity are powerful tools in reducing diabetes and cardiometabolic risk. Various international scientific and health organizations have advocated the use of new technologies to solve these problems. The PREDIRCAM project explores the contribution that a technological system could offer for the continuous monitoring of lifestyle habits and individualized treatment of obesity as well as cardiometabolic risk prevention. Methods: PREDIRCAM is a technological platform for patients and professionals designed to improve the effectiveness of lifestyle behavior modifications through the intensive use of the latest information and communication technologies. The platform consists of a web-based application providing communication interface with monitoring devices of physiological variables, application for monitoring dietary intake, ad hoc electronic medical records, different communication channels, and an intelligent notification system. A 2-week feasibility study was conducted in 15 volunteers to assess the viability of the platform. Results: The website received 244 visits (average time/session: 17 min 45 s). A total of 435 dietary intakes were recorded (average time for each intake registration, 4 min 42 s ± 2 min 30 s), 59 exercises were recorded in 20 heart rate monitor downloads, 43 topics were discussed through a forum, and 11 of the 15 volunteers expressed a favorable opinion toward the platform. Food intake recording was reported as the most laborious task. Ten of the volunteers considered long-term use of the platform to be feasible. Conclusions: The PREDIRCAM platform is technically ready for clinical evaluation. Training is required to use the platform and, in particular, for registration of dietary food intake

Highly regular hexagonally-arranged nanostructures on Ni-W alloy tapes upon Irradiation with ultrashort UV laser pulses

This article belongs to the Special Issue Dynamics and Processes at Laser-Irradiated Surfaces—A Themed Issue in Honor of the 70th Birthday of Professor Jürgen Reif.Nickel tungsten alloy tapes (Ni—5 at% W, 10 mm wide, 80 µm thick, biaxially textured) used in second-generation high temperature superconductor (2G-HTS) technology were laser-processed in air with ultraviolet ps-laser pulses (355 nm wavelength, 300 ps pulse duration, 250–800 kHz pulse repetition frequency). By employing optimized surface scan-processing strategies, various laser-generated periodic surface structures were generated on the tapes. Particularly, distinct surface microstructures and nanostructures were formed. These included sub-wavelength-sized highly-regular hexagonally-arranged nano-protrusions, wavelength-sized line-grating-like laser-induced periodic surface structures (LIPSS, ripples), and larger irregular pyramidal microstructures. The induced surface morphology was characterized in depth by electron-based techniques, including scanning electron microscopy (SEM), electron back scatter diffraction (EBSD), cross-sectional transmission electron microscopy (STEM/TEM) and energy dispersive X-ray spectrometry (EDS). The in-depth EBSD crystallographic analyses indicated a significant impact of the material initial grain orientation on the type of surface nanostructure and microstructure formed upon laser irradiation. Special emphasis was laid on high-resolution material analysis of the hexagonally-arranged nano-protrusions. Their formation mechanism is discussed on the basis of the interplay between electromagnetic scattering effects followed by hydrodynamic matter re-organization after the laser exposure. The temperature stability of the hexagonally-arranged nano-protrusion was explored in post-irradiation thermal annealing experiments, in order to qualify their suitability in 2G-HTS fabrication technology with initial steps deposition temperatures in the range of 773–873 K.The authors gratefully acknowledge the financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) ARDEB 1001 (project number: 117F399) program, the Spanish MCIN/AEI/10.13039/501100011033 (project PID2020-113034RB-I00), the LaserImplant project (European Union’s Horizon 2020 research and innovation program under grant agreement No. 951730) and from Gobierno de Aragón (research group T54_20R).Peer reviewe

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Technological solutions and laser processes for the development of superconductor-based applications

Memoria presentada por Álvaro Cubero Ruiz para optar al grado de Doctor en Física.El trabajo realizado en esta tesis doctoral aborda diferentes retos asociados con la implantación de tecnología superconductora en diversas aplicaciones. En la primera parte, se analiza la estabilidad térmica de cables y bobinas superconductoras. En particular, se ha estudiado la generación y propagación de quench en cables de diboruro de magnesio (MgB2) con geometría Rutherford. Se han empleado dos configuraciones para estudiar la dinámica de quench en estos conductores: la generación de calor localizada, simulando un punto caliente gracias a un calentador externo; y la aplicación de sobrecorrientes (corrientes por encima de la corriente crítica del cable). Además, se ha analizado la estabilidad térmica de una bobina tipo doble pancake fabricada con cinta de material superconductor de alta temperatura de segunda generación (2G-HTS), la cual se bobinó de forma continua y sin aislamiento entre espiras. La bobina se ancló térmicamente al dedo frío de un crio-generador para ser enfriada por conducción. Se ha analizado el comportamiento térmico y electromagnético de esta bobina incluyendo los procesos de carga y de descarga, la medida de la corriente crítica de la bobina, las pérdidas generadas, y sus diferentes contribuciones, durante las rampas de carga y descarga, así como la conductancia térmica que se establece en las diferentes uniones térmicas que se han utilizado para refrigerar la bobina. Para poder realizar estos estudios fue necesario inyectar de forma estable corrientes por encima de los 400 A. Esto supuso un reto por el calor generado en el equipo y en las barras de corriente, con un extremo a temperatura ambiente y otro a temperaturas criogénicas, por lo que son necesarios disipadores térmicos, que deben tener buena conductancia térmica y aislamiento eléctrico. En esta tesis se ha propuesto para esta aplicación emplear piezas de cobre recubiertas por una capa de alúmina proyectada por plasma, que es posteriormente densificada y re-fundida mediante el procesado láser de superficies, consiguiendo así una mejora notable de su conductividad térmica. Otro de los objetivos que se han abordado en este trabajo fue estudiar si las propiedades superconductoras pueden verse modificadas por la interacción con radiación láser. La versatilidad de las tecnologías láser permite facilitar la formación de nanoestructuras en la superficie del material con una disposición casi periódica, lo que abre un nuevo camino a la ingeniería de superficies. En esta tesis se ha estudiado como los tratamientos láser pueden modificar las propiedades superconductoras del material. Para estos estudios se han utilizado muestras de niobio por ser el elemento puro superconductor con una temperatura crítica y campos magnéticos críticos más altos. Dichas estructuras han sido generadas con distintos láseres: un láser ultravioleta con pulsos en el rango de cientos de picosegundos, y dos láseres que emiten pulsos en el infrarrojo cercano en el rango de los femtosegundos. Además, se han estudiado tratamientos en diferentes atmósferas. Esta modificación superficial es de gran interés para una aplicación directa del material, como es la construcción de cavidades resonantes de radio frecuencia.Agradecer también a las entidades públicas Ministerio y Gobierno de Aragón, por los fondos y los medios para hacer posible esta tesis englobando contrato predoctoral, ayuda para estancia y congresos varios.Peer reviewe