Las tutorías virtuales en la formación de profesores de matemáticas

En este trabajo se presenta una experiencia de formación de maestros en nuevas tecnologías para la enseñanza de las matemáticas utilizando un modelo de enseñanza-aprendizaje semipresencial basado en un entorno de trabajo WebCT. Se describe el diseño y estructura del curso así como algunas incidencias ocurridas durante el mismo y se analizan los cambios que se producen en las tutorías respecto a una dinámica de docencia presencial

Las tutorías virtuales en la formación de profesores en matemáticas

Presentamos una experiencia de tutorías virtuales llevadas a cabo durante el desarrollo de la asignatura optativa “Nuevas Tecnologías en la Enseñanza de las Matemáticas” del título de Maestro de la Universidad de Almería. Esta experiencia se ha realizado siguiendo un modelo de enseñanza semipresencial y en ella se ha puesto de manifiesto que las tutorías en entornos virtuales van más allá, en posibilidades, de las funciones atribuibles en un modelo de enseñanza presencial, en particular en lo relativo a las tutorías como apoyo a la actividad académica

Modeling and optimization of frequencies on congested bus lines

In this paper some mathematical programming models are exposed in order to set the number of services on a specified system of bus lines, which are intended to assist high demand levels which may arise because of the disruption of Rapid Transit services or during the celebration of massive events. By means of this model two types of basic magnitudes can be determined, basically: a) the number of bus units assigned to each line and b) the number of services that should be assigned to those units. In these models, passenger flow assignment to lines can be considered of the system optimum type, in the sense that the assignment of units and of services is carried out minimizing a linear combination of operation costs and total travel time of users. The models consider delays experienced by buses as a consequence of the get in/out of the passengers, queueing at stations and the delays that passengers experience waiting at the stations. For the case of a congested strategy based user optimal passenger assignment model with strict capacities on the bus lines, the use of the method of successive averages is shown

Variable-based multi-module data caches for clustered VLIW processors

Memory structures consume an important fraction of the total processor energy. One solution to reduce the energy consumed by cache memories consists of reducing their supply voltage and/or increase their threshold voltage at an expense in access time. We propose to divide the L1 data cache into two cache modules for a clustered VLIW processor consisting of two clusters. Such division is done on a variable basis so that the address of a datum determines its location. Each cache module is assigned to a cluster and can be set up as a fast power-hungry module or as a slow power-aware module. We also present compiler techniques in order to distribute variables between the two cache modules and generate code accordingly. We have explored several cache configurations using the Mediabench suite and we have observed that the best distributed cache organization outperforms traditional cache organizations by 19%-31% in energy-delay and by 11%-29% in energy-delay. In addition, we also explore a reconfigurable distributed cache, where the cache can be reconfigured on a context switch. This reconfigurable scheme further outperforms the best previous distributed organization by 3%-4%.Peer ReviewedPostprint (published version

Bond graph simulation of error propagation in position estimation of a hydraulic cylinder using low cost accelerometers

The indirect calculation from acceleration of transversal displacement of the piston inside the body of a double effect linear hydraulic cylinder during its operating cycle is assessed. Currently an extensive effort exists in the improvement of the mechanical and electronic design of the highly sophisticated MEMS accelerometers. Nevertheless, the predictable presence of measurement errors in the current commercial accelerometers is the main origin of velocity and displacement measurement deviations during integration of the acceleration. A bond graph numerical simulation model of the electromechanical system has been developed in order to forecast the effect of several measurement errors in the use of low cost two axes accelerometers. The level of influence is assessed using quality indicators and visual signal evaluation, for both simulations and experimental results. The obtained displacements results are highly influenced by the diverse dynamic characteristics of each measuring axis. The small measuring errors of a simulated extremely high performance sensor generate only moderate effects in longitudinal displacement but deep deviations in the reconstruction of piston transversal movements. The bias error has been identified as the source of the higher deviations of displacement results; although, its consequences can be easily corrected.Peer ReviewedPostprint (published version

Experimental study of 3D movement in cushioning of hydraulic cylinder

A double acting cylinder operation has been fully monitored in its key functional parameters, focused on characterization of end-of-stroke cushioning and starting phases. Being the cylinder performance reliant in the piston constructive geometry, the number and location of piston circumferential grooves is a significant parameter affecting the internal cushioning system performance. An eddy current displacement sensor assembled in the piston allows assessment of piston radial displacement inside the cylinder tube, which is directly related with the studied operating phases. Due to such 3D displacements, the piston becomes as an active and self-adjusting element along the functional cycle of the cylinder. Mechanical joints orientation and operating pressure are also relevant parameters affecting piston radial displacement and, thus, the cushioning and starting performance. Computational Fluid Dynamics (CFD) results confirm the observed functional role of the perimeter grooves; the flow and pressure distributions, where develops a significant radial force, are also in accordance with the registered radial displacement.Peer ReviewedPostprint (published version

Image hashing for loop closing in underwater visual SLAM

This article presents an experimental assessment of a hash-based loop closure detection methodology specially addressed to Multi-robot underwater visual Simultaneous Localization and Mapping (SLAM). This methodology uses two diferent top quality image global descriptors, one learned (NetVLAD) and one handcrafted (HALOC). Complete tests were done to compare the performance of both hashing techniques applied in an extensive set of real underwater imagery.Peer Reviewe

Comparative study of energy management strategies in collaborative microgrids of domestic prosumers

An optimization model is proposed to manage a residential microgrid including a charging spot with a vehicle-togrid system and renewable energy sources. We consider the microgrid operated in grid-connected mode. The model is executed one-day-ahead and generates a schedule for all components of the microgrid. The microgrids are ubicated in Xermade, Galicia, Spain.Postprint (published version

Las tutorías virtuales en la formación de profesores en matemáticas

En este trabajo se presenta una experiencia de formación de maestros en nuevas tecnologías para la enseñanza de las matemáticas utilizando un modelo de enseñanza-aprendizaje semipresencial basado en un entorno de trabajo WebCT. Se describe el diseño y estructura del curso así como algunas incidencias ocurridas durante el mismo y se analizan los cambios que se producen en las tutorías respecto a una dinámica de docencia presencial.Eje: Educación universitaria: Experiencias uso NTICRed de Universidades con Carreras en Informática (RedUNCI

GeroMAG: in-house prototype of an innovative sealed, compact and non-shaft-driven gerotor pump with magnetically-driving outer rotor

The technology of gerotor pumps is progressing towards cutting-edge applications in emerging sectors, which are more demanding for pump performance. Moreover, recent environmental standards are heading towards leakage-free and noiseless hydraulic systems. Hence, in order to respond to these demands, this study, which will be referred to as the GeroMAG concept, aims to make a leap from the standard gerotor pump technology: a sealed, compact, non-shaft-driven gerotor pump with a magnetically-driving outer rotor. The GeroMAG pump is conceived as a variable-flow pump to accomplish a standard volumetric flow rate at low rotational speed with satisfactory volumetric efficiency. By following the authors’ methodology based on a catalogue of best-practice rules, a custom trochoidal gear set is designed. Then, two main technological challenges are encountered: how to generate the rotational movement of the driving outer rotor and how to produce the guide of rotation of the gear set once there is no drive shaft. To confront them, a quiet magnet brushless motor powers the driving outer rotor through pole pieces placed in its external sideway and the rotational movement is guided by the inner edgewise pads carved on it. Subsequently, GeroMAG pump architecture, prototype, housing, methodology, materials and manufacture will be presented. As a principal conclusion, the GeroMAG proof of concept and pump prototype are feasible, which is corroborated by experimental results and performance indexes.Peer ReviewedPostprint (published version