Ring Resonators with Sagnac Loops for Photonic Processing in DWDM Backbone Networks

In this paper, optical configurations based on ring resonators (RR) with an internal Sagnac (SG) loop in the feedback path, are analyzed in terms of their amplitude response and dispersive properties for filtering and chromatic dispersion managing in digital transmission systems over amplified single- mode fiber (SMF) spans in DWDM backbone networks. Design issues for the architecture as regards quadratic dispersion and magnitude distortion are provided. The RR+SG compound filter provides frequency tunability of the amplitude and dispersion peaks by adjusting a coupling coefficient of an optical coupler, with no need for using integrated thermo-optic nor current- injection based phase shifters. The configuration can be employed as an additional structure for a general RR-based design and synthesis architecture, allowing bandwidth increase of dispersion compensators and flexibility. The performance of a compound filter consisting of a two RR in series stage and a RR+SG filter are reported as a more compact and effective solution for existing multi-channel SMF backbone links operating at high bit rates. Design guidelines of an integrated ring resonator based on polymer technology for showing feasibility of the proposal is reported.This work was partially supported by Spanish CICYT (TEC2006-13273-C03-03-MIC), European project NoE EPhoton/One+, CAM (FACTOTEM-CM:S-0505/ESP/000417), FENIS-CCG06-UC3MITIC-0619.Publicad

Radio-frequency ring resonators for self-referencing fiber-optic intensity sensors

A theoretical and experimental study of radiofrequency ring resonators (RR) for referencing and improving the sensitivity of fiber-optic intensity sensors (FOS) is reported. The separation between lead and transducer losses in the FOS is solved by converting the light intensity fluctuations to be measured into RR losses that produce high amplitude variations in the proximity of the RR resonance frequencies. Two different self-referencing techniques are developed. Via the definition of the measurement parameter RM , sensor linearity and sensitivity are analyzed. A calibration using an optical attenuator is reported to validate the model.Publicad

Evaluación de errores de futuros profesores en la construcción de gráficos estadísticos

Se analizan los gráficos producidos por 207 futuros profesores de educación primaria al resolver una tarea abierta en la que tenían que comparar dos distribuciones. Los gráficos producidos se clasifican según su corrección y se describen los errores en la selección y construcción de gráficos. Los resultados muestran gran diversidad de errores, la mayoría relacionados con las escalas y otros, conceptuales o relacionados con convenios de construcción de los distintos gráficos. Se analiza también la influencia del uso del ordenador en los errores encontrados

Comparación de distribuciones por futuros profesores

Este estudio tiene como objetivo analizar las estrategias usadas por los futuros profesores de educación primaria para comparar dos distribuciones de datos. Los resultados obtenidos en una muestra de 135 futuros profesores en una tarea abierta indican dificultades en la interpretación de medidas de posición central y escaso uso de las medidas de dispersión

De la mesa de dibujo a La Jungla

Nuestro departamento de investigación y desarrollo ha estado trabajando en una solución de alojamiento con los requisitos de mejorar la logística, el montaje, la flexibilidad, el aprovechamiento de los recursos naturales y, sobre todo, la mejora de las condiciones de habitabilidad. Finalmente volvimos a sistemas de arquitectura más tradicional, combinándolos con materiales tecnológicos avanzados

Optimized Design of Hot Water Storage in Solar Thermal Cooling Facilities

Solar thermal installations can provide a significant contribution to the energy needs of cooling demand of single family buildings. Unfortunately oversizing facility elements is not uncommon. Most of the design flaws concern collector field or auxiliary elements, such as backup boilers or electric resistances inside storage devices. This leads to lower than expected facility COP and SCOP, but also higher cost. Customer dissatisfaction is the result. This paper presents a numerical model of the multiple purpose solar thermal facility installed at Universidad Carlos III de Madrid (UC3M) using the TRNSYS® tool. The solar cooling facility (http://termica.uc3m.es/solar.htm) is completely monitored for its performance characterization in the production of AC, DHW and heating. Operational data for various summer seasons have been recorded, simultaneously with 7 meteorological variables. The experimental facility includes a single effect BrLi absorption chiller working at part load under summer season. TRNSYS is a completely feasible platform for simulating solar facilities and is commonly used by researchers and planners, for its simplicity and ease manipulation. This simulation tool contains general solar cooling elements found in most experimental facilities and has been kept as simple as possible. The model developed aims at analyzing facility elements in order to resize collector field and storage volumes. Furthermore it allows studying different configurations of the facility and the control schemes. These configurations include different hot water storage capacities within the facility allowing comparing with the facility without any kind of storage excepting its own thermal inertia. The simulation has been validated with instantaneous and seasonal experimental data for different summer seasons including 2003, 2004 and 2005. Simulation results show that there is a hot storage tank capacity that optimizes the facility in terms of COP, SCOP and total cold produced. Even with no storage at all, the facility still improves its behavior from current operating conditions. Simulation and experimental results are compared and an optimum configuration of the facility is proposed.Universidad Carlos III de Madrid - ITEA Research GroupPublicad

Estimación de la asociación por estudiantes de psicología

Las tablas de contingencia son un instrumento necesario en el trabajo de los profesionales de psicología y, en general, en ciencias de la salud, pues la emisión de un diagnóstico requiere del juicio de asociación sobre dos variables cuyos datos se presentan en una tabla de contingencia. En este trabajo describimos un estudio exploratorio de la percepción de la asociación y estimación de su intensidad en tablas de contingencia en una muestra de estudiantes de psicología (62 estudiantes de la Universidad de Granada y 62 de la Universidad de Huelva). Comparamos los resultados obtenidos entre las dos universidades, y además comparamos nuestros resultados con un estudio previo de Estepa (1993) con estudiantes de bachillerato

The development of wind energy in Galicia: public policies, effects on the economy and international comparison

Nowadays energy constitutes a very important concern of policy and public debate. It is justified by the effects of climate change and the national strategies to be self-sufficient in the supply of energy. Renewable energies are the alternative and public policies could play a key role in their development. Furthermore, those energies have potential to contribute to the endogenous development. In this paper we study the development of wind energy in Galicia (the most important renewable energy in terms of contribution to the energy balance) and the role of public policy in promotion of this type of energy. Its development is a recent phenomena but with a growing relevance, because of their impact in the regional economy. For this reason, we analyse the effects of this sector in the economy (employment, manufacturing production, exports, imports...) Moreover, we also compare the Galician model with the Denmark one, because it has a truly known successful integrated framework, in which, all the economical agents collaborate in order to build a competitive and innovated sector with several spill-over effects.