Transductor óptico-sonoro basado en procesado de imagen

En este proyecto se aborda la transducción óptico-sonora utilizando métodos de tratamiento digital de imagen. Para llevar a cabo el proyecto se consideran únicamente métodos de bajo presupuesto, por lo que para realizar todo el proceso de conversión óptico-sonora se utilizan un ordenador y un escáner doméstico. Como el principal objetivo del proyecto es comprobar si es viable utilizar el tratamiento digital de imagen como conversor no se ha contemplado la utilización de equipamiento profesional. La utilidad de este proyecto está en la restauración del sonido de material fílmico con importantes degradaciones, tales que no sea posible su reproducción en un proyector. Con el prototipo que se propone, realizado con el software de programación Matlab, se consigue digitalizar el audio analógico de las películas en malas condiciones ya que la captura de audio se efectúa de manera óptica sobre las bandas sonoras. Lo conseguido en este proyecto cobra especial importancia si se tiene en cuenta la cantidad de material cinematográfico que hay en películas de celulosa. La conservación de dicho material requiere unas condiciones de almacenamiento muy específicas para que el soporte no se vea afectado, pero con el paso del tiempo es habitual que las bobinas de película presenten deformaciones o incluso ruptura. Aplicando métodos de tratamiento digital de imagen es posible restaurar el audio de fragmentos de película que no puedan ser expuestos a la tensión producida por los rodillos de los proyectores, incluso es posible recuperar el audio de fotogramas concretos ya que la digitalización del audio se realiza capturando la imagen de la forma de onda. Por ello, el procedimiento seguido para digitalizar la película debe ser poco intrusivo para garantizar la conservación del soporte fílmico. Cabe destacar que en este proyecto se ha realizado la conversión óptico-sonora sobre las bandas de sonido analógicas de área variable presentes en la película, pero el procedimiento es aplicable también a las bandas de área variable realizando modificaciones en el prototipo. Esto último queda fuera del objetivo de este proyecto, pero puede ser un trabajo futuro. ABSTRACT This project addresses optical to sound conversion using digital image processing methods. To carry out the project are considered only low-budget methods , so for all optical to sound conversion process using a computer and a home scanner . As the main application of this project is to test the feasibility of using the digital image processing as a converter does not contemplate the use of professional equipment. The main objective of this project is the restoration of sound film material with significant impairments , such is not possible playback on a projector. With the proposed prototype , made with Matlab programming software , you get digitize analog audio bad movies because the audio capture is performed optically on the soundtracks. The achievements in this project is especially important if you consider the amount of film material is in cellulose films . The preservation of such material requires a very specific storage conditions to which the support is not affected , but over time it is common for film reels presenting deformations or even rupture. Applying methods of digital image processing is possible to restore the audio from movie clips that can not be exposed to the tension produced by the rollers of the projectors , it is even possible to retrieve specific frames audio and audio that digitization is done by capturing the image of the waveform. Therefore, the procedure used to digitize the film should be bit intrusive to ensure the conservation of the film medium. Note that in this project was carried out optical to sound conversion on analog variable area soundtracks present in the film, but the procedure is applicable to variable-area bands making changes to the prototype. The latter is beyond the scope of this project, but can be a future work.

Radiation heat savings in polysilicon production: validation of results through a CVD laboratory prototype

This work aims at a deeper understanding of the energy loss phenomenon in polysilicon production reactors by the so-called Siemens process. Contributions to the energy consumption of the polysilicon deposition step are studied in this paper, focusing on the radiation heat loss phenomenon. A theoretical model for radiation heat loss calculations is experimentally validated with the help of a laboratory CVD prototype. Following the results of the model, relevant parameters that directly affect the amount of radiation heat losses are put forward. Numerical results of the model applied to a state-of-the-art industrial reactor show the influence of these parameters on energy consumption due to radiation per kilogram of silicon produced; the radiation heat loss can be reduced by 3.8% when the reactor inner wall radius is reduced from 0.78 to 0.70 m, by 25% when the wall emissivity is reduced from 0.5 to 0.3, and by 12% when the final rod diameter is increased from 12 to 15 cm.

A new PET prototype for proton therapy: comparison of data and Monte Carlo simulations

Ion beam therapy is a valuable method for the treatment of deep-seated and radio-resistant tumors thanks to the favorable depth-dose distribution characterized by the Bragg peak. Hadrontherapy facilities take advantage of the specific ion range, resulting in a highly conformal dose in the target volume, while the dose in critical organs is reduced as compared to photon therapy. The necessity to monitor the delivery precision, i.e. the ion range, is unquestionable, thus different approaches have been investigated, such as the detection of prompt photons or annihilation photons of positron emitter nuclei created during the therapeutic treatment. Based on the measurement of the induced β+ activity, our group has developed various in-beam PET prototypes: the one under test is composed by two planar detector heads, each one consisting of four modules with a total active area of 10 × 10 cm2. A single detector module is made of a LYSO crystal matrix coupled to a position sensitive photomultiplier and is read-out by dedicated frontend electronics. A preliminary data taking was performed at the Italian National Centre for Oncological Hadron Therapy (CNAO, Pavia), using proton beams in the energy range of 93–112 MeV impinging on a plastic phantom. The measured activity profiles are presented and compared with the simulated ones based on the Monte Carlo FLUKA package.

Evaluation of three solar and daylighting control systems based on Calumen II, Ecotect and Radiance simulation programs to obtain an energy efficient and healthy interior in the experimental building prototype SDE10

Evaluation of three solar and daylighting control systems based on Calumen II, Ecotect and Radiance simulation programs to obtain an energy efficient and healthy interior in the experimental building prototype SDE10

Prototype of EN 301 549 Decision tree

The new European Standard EN 301 549 “Accessibility requirements suitable for public procurement of ICT products and services in Europe” is the response by CEN, CENELEC and ETSI to the European Commission’s Mandate 376. Today, ICT products and services are converging, and the boundaries between product categories are being constantly blurred. For that reason EN 301 549 has been drafted using a feature-based approach, instead of being based on product categories. The result is a standard that can be applied to any ICT product and service, by identifying applicable requirements depending on the features of the ICT. This demonstration presents ongoing work at the research group CETTICO of the Technical University of Madrid. CETTICO is developing a workgroup-based support tool where teams of people can annotate the result of performing a conformity assessment of a given ICT product or service according to the requirements of the EN. One of the functions of the tool is creating evaluation projects. During that task the user defines the features of the corresponding ICT product or service by answering questions presented by the tool. As a result of this process, the tool will create a list of applicable requirements and recommendations.

Uncertainty in ellipse fitting using a flatbed scanner: development and experimental verification

In the field of dimensional metrology, the use of optical measuring machines requires the handling of a large number of measurement points, or scanning points, taken from the image of the measurand. The presence of correlation between these measurement points has a significant influence on the uncertainty of the result. The aim of this work is the development of an estimation procedure for the uncertainty of measurement in a geometrically elliptical shape, taking into account the correlation between the scanning points. These points are obtained from an image produced using a commercial flat bed scanner. The characteristic parameters of the ellipse (coordinates of the center, semi-axes and the angle of the semi-major axis with regard to the horizontal) are determined using a least squares fit and orthogonal distance regression. The uncertainty is estimated using the information from the auto-correlation function of the residuals and is propagated through the fitting algorithm according to the rules described in Evaluation of Measurement Data—Supplement 2 to the ‘Guide to the Expression of Uncertainty in Measurement’—Extension to any number of output quantities. By introducing the concept of cut-off length, it can be observed how it is possible to take into account the presence of the correlation in the estimation of uncertainty in a very simple way while avoiding underestimation.

High power beam dump project for the accelerator prototype LIPAc: Cooling design and analysis

En el campo de la fusión nuclear y desarrollándose en paralelo a ITER (International Thermonuclear Experimental Reactor), el proyecto IFMIF (International Fusion Material Irradiation Facility) se enmarca dentro de las actividades complementarias encaminadas a solucionar las barreras tecnológicas que aún plantea la fusión. En concreto IFMIF es una instalación de irradiación cuya misión es caracterizar materiales resistentes a condiciones extremas como las esperadas en los futuros reactores de fusión como DEMO (DEMOnstration power plant). Consiste de dos aceleradores de deuterones que proporcionan un haz de 125 mA y 40 MeV cada uno, que al colisionar con un blanco de litio producen un flujo neutrónico intenso (1017 neutrones/s) con un espectro similar al de los neutrones de fusión [1], [2]. Dicho flujo neutrónico es empleado para irradiar los diferentes materiales candidatos a ser empleados en reactores de fusión, y las muestras son posteriormente examinadas en la llamada instalación de post-irradiación. Como primer paso en tan ambicioso proyecto, una fase de validación y diseño llamada IFMIFEVEDA (Engineering Validation and Engineering Design Activities) se encuentra actualmente en desarrollo. Una de las actividades contempladas en esta fase es la construcción y operación de una acelarador prototipo llamado LIPAc (Linear IFMIF Prototype Accelerator). Se trata de un acelerador de deuterones de alta intensidad idéntico a la parte de baja energía de los aceleradores de IFMIF. Los componentes del LIPAc, que será instalado en Japón, son suministrados por diferentes países europeos. El acelerador proporcionará un haz continuo de deuterones de 9 MeV con una potencia de 1.125 MW que tras ser caracterizado con diversos instrumentos deberá pararse de forma segura. Para ello se requiere un sistema denominado bloque de parada (Beam Dump en inglés) que absorba la energía del haz y la transfiera a un sumidero de calor. España tiene el compromiso de suministrar este componente y CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) es responsable de dicha tarea. La pieza central del bloque de parada, donde se para el haz de iones, es un cono de cobre con un ángulo de 3.5o, 2.5 m de longitud y 5 mm de espesor. Dicha pieza está refrigerada por agua que fluye en su superficie externa por el canal que se forma entre el cono de cobre y otra pieza concéntrica con éste. Este es el marco en que se desarrolla la presente tesis, cuyo objeto es el diseño del sistema de refrigeración del bloque de parada del LIPAc. El diseño se ha realizado utilizando un modelo simplificado unidimensional. Se han obtenido los parámetros del agua (presión, caudal, pérdida de carga) y la geometría requerida en el canal de refrigeración (anchura, rugosidad) para garantizar la correcta refrigeración del bloque de parada. Se ha comprobado que el diseño permite variaciones del haz respecto a la situación nominal siendo el flujo crítico calorífico al menos 2 veces superior al nominal. Se han realizado asimismo simulaciones fluidodinámicas 3D con ANSYS-CFX en aquellas zonas del canal de refrigeración que lo requieren. El bloque de parada se activará como consecuencia de la interacción del haz de partículas lo que impide cualquier cambio o reparación una vez comenzada la operación del acelerador. Por ello el diseño ha de ser muy robusto y todas las hipótesis utilizadas en la realización de éste deben ser cuidadosamente comprobadas. Gran parte del esfuerzo de la tesis se centra en la estimación del coeficiente de transferencia de calor que es determinante en los resultados obtenidos, y que se emplea además como condición de contorno en los cálculos mecánicos. Para ello por un lado se han buscado correlaciones cuyo rango de aplicabilidad sea adecuado para las condiciones del bloque de parada (canal anular, diferencias de temperatura agua-pared de decenas de grados). En un segundo paso se han comparado los coeficientes de película obtenidos a partir de la correlación seleccionada (Petukhov-Gnielinski) con los que se deducen de simulaciones fluidodinámicas, obteniendo resultados satisfactorios. Por último se ha realizado una validación experimental utilizando un prototipo y un circuito hidráulico que proporciona un flujo de agua con los parámetros requeridos en el bloque de parada. Tras varios intentos y mejoras en el experimento se han obtenido los coeficientes de película para distintos caudales y potencias de calentamiento. Teniendo en cuenta la incertidumbre de las medidas, los valores experimentales concuerdan razonablemente bien (en el rango de 15%) con los deducidos de las correlaciones. Por motivos radiológicos es necesario controlar la calidad del agua de refrigeración y minimizar la corrosión del cobre. Tras un estudio bibliográfico se identificaron los parámetros del agua más adecuados (conductividad, pH y concentración de oxígeno disuelto). Como parte de la tesis se ha realizado asimismo un estudio de la corrosión del circuito de refrigeración del bloque de parada con el doble fin de determinar si puede poner en riesgo la integridad del componente, y de obtener una estimación de la velocidad de corrosión para dimensionar el sistema de purificación del agua. Se ha utilizado el código TRACT (TRansport and ACTivation code) adaptándalo al caso del bloque de parada, para lo cual se trabajó con el responsable (Panos Karditsas) del código en Culham (UKAEA). Los resultados confirman que la corrosión del cobre en las condiciones seleccionadas no supone un problema. La Tesis se encuentra estructurada de la siguiente manera: En el primer capítulo se realiza una introducción de los proyectos IFMIF y LIPAc dentro de los cuales se enmarca esta Tesis. Además se describe el bloque de parada, siendo el diseño del sistema de rerigeración de éste el principal objetivo de la Tesis. En el segundo y tercer capítulo se realiza un resumen de la base teórica así como de las diferentes herramientas empleadas en el diseño del sistema de refrigeración. El capítulo cuarto presenta los resultados del relativos al sistema de refrigeración. Tanto los obtenidos del estudio unidimensional, como los obtenidos de las simulaciones fluidodinámicas 3D mediante el empleo del código ANSYS-CFX. En el quinto capítulo se presentan los resultados referentes al análisis de corrosión del circuito de refrigeración del bloque de parada. El capítulo seis se centra en la descripción del montaje experimental para la obtención de los valores de pérdida de carga y coeficiente de transferencia del calor. Asimismo se presentan los resultados obtenidos en dichos experimentos. Finalmente encontramos un capítulo de apéndices en el que se describen una serie de experimentos llevados a cabo como pasos intermedios en la obtención del resultado experimental del coeficiente de película. También se presenta el código informático empleado para el análisis unidimensional del sistema de refrigeración del bloque de parada llamado CHICA (Cooling and Heating Interaction and Corrosion Analysis). ABSTRACT In the nuclear fusion field running in parallel to ITER (International Thermonuclear Experimental Reactor) as one of the complementary activities headed towards solving the technological barriers, IFMIF (International Fusion Material Irradiation Facility) project aims to provide an irradiation facility to qualify advanced materials resistant to extreme conditions like the ones expected in future fusion reactors like DEMO (DEMOnstration Power Plant). IFMIF consists of two constant wave deuteron accelerators delivering a 125 mA and 40 MeV beam each that will collide on a lithium target producing an intense neutron fluence (1017 neutrons/s) with a similar spectra to that of fusion neutrons [1], [2]. This neutron flux is employed to irradiate the different material candidates to be employed in the future fusion reactors, and the samples examined after irradiation at the so called post-irradiative facilities. As a first step in such an ambitious project, an engineering validation and engineering design activity phase called IFMIF-EVEDA (Engineering Validation and Engineering Design Activities) is presently going on. One of the activities consists on the construction and operation of an accelerator prototype named LIPAc (Linear IFMIF Prototype Accelerator). It is a high intensity deuteron accelerator identical to the low energy part of the IFMIF accelerators. The LIPAc components, which will be installed in Japan, are delivered by different european countries. The accelerator supplies a 9 MeV constant wave beam of deuterons with a power of 1.125 MW, which after being characterized by different instruments has to be stopped safely. For such task a beam dump to absorb the beam energy and take it to a heat sink is needed. Spain has the compromise of delivering such device and CIEMAT (Centro de Investigaciones Energéticas Medioambientales y Tecnológicas) is responsible for such task. The central piece of the beam dump, where the ion beam is stopped, is a copper cone with an angle of 3.5o, 2.5 m long and 5 mm width. This part is cooled by water flowing on its external surface through the channel formed between the copper cone and a concentric piece with the latter. The thesis is developed in this realm, and its objective is designing the LIPAc beam dump cooling system. The design has been performed employing a simplified one dimensional model. The water parameters (pressure, flow, pressure loss) and the required annular channel geometry (width, rugoisty) have been obtained guaranteeing the correct cooling of the beam dump. It has been checked that the cooling design allows variations of the the beam with respect to the nominal position, being the CHF (Critical Heat Flux) at least twice times higher than the nominal deposited heat flux. 3D fluid dynamic simulations employing ANSYS-CFX code in the beam dump cooling channel sections which require a more thorough study have also been performed. The beam dump will activateasaconsequenceofthe deuteron beam interaction, making impossible any change or maintenance task once the accelerator operation has started. Hence the design has to be very robust and all the hypotheses employed in the design mustbecarefully checked. Most of the work in the thesis is concentrated in estimating the heat transfer coefficient which is decisive in the obtained results, and is also employed as boundary condition in the mechanical analysis. For such task, correlations which applicability range is the adequate for the beam dump conditions (annular channel, water-surface temperature differences of tens of degrees) have been compiled. In a second step the heat transfer coefficients obtained from the selected correlation (Petukhov- Gnielinski) have been compared with the ones deduced from the 3D fluid dynamic simulations, obtaining satisfactory results. Finally an experimental validation has been performed employing a prototype and a hydraulic circuit that supplies a flow with the requested parameters in the beam dump. After several tries and improvements in the experiment, the heat transfer coefficients for different flows and heating powers have been obtained. Considering the uncertainty in the measurements the experimental values agree reasonably well (in the order of 15%) with the ones obtained from the correlations. Due to radiological reasons the quality of the cooling water must be controlled, hence minimizing the copper corrosion. After performing a bibligraphic study the most adequate water parameters were identified (conductivity, pH and dissolved oxygen concentration). As part of this thesis a corrosion study of the beam dump cooling circuit has been performed with the double aim of determining if corrosion can pose a risk for the copper beam dump , and obtaining an estimation of the corrosion velocitytodimension the water purification system. TRACT code(TRansport and ACTivation) has been employed for such study adapting the code for the beam dump case. For such study a collaboration with the code responsible (Panos Karditsas) at Culham (UKAEA) was established. The work developed in this thesis has supposed the publication of three articles in JCR journals (”Journal of Nuclear Materials” y ”Fusion Engineering and Design”), as well as presentations in more than four conferences and relevant meetings.

Design evaluation of a prototype user interface to support a guideline-based decision support system in gestational diabetes

Gestational Diabetes (GD) has increased over the last 20 years, affecting up to 15% of pregnant women worldwide. The complications associated can be reduced with the appropriate glycemic control during the pregnancy.

Prototype emitter for use in subsurface drip irrigation: Manufacturing, hydraulic evaluation and experimental analyses

The current research aims to analyse theoretically and evaluate a self-manufactured simple design for subsurface drip irrigation (SDI) emitter to avoid root and soil intrusion. It was composed of three concentric cylindrical elements: an elastic silicone membrane; a polyethylene tube with two holes drilled on its wall for water discharge; and a vinyl polychloride protector system to wrap the other elements. The discharge of the emitter depends on the change in the membrane diameter when it is deformed by the water pressure. The study of the operation of this emitter is a new approach that considers mechanical and hydraulic principles. Thus, the estimation on the membrane deformation was based on classical mechanical stress theories in composite cylinders. The hydraulic principles considered the solid deformation due to force based on water pressure and the general Darcy–Weisbach head-loss equation. Twenty emitter units, with the selected design, were handcrafted in a lathe and were used in this study. The measured pressure/discharge relationship for the emitters showed good agreement with that calculated by the theoretical approach. The variation coefficient of the handcrafted emitters was high compared to commercial emitters. Results from field evaluations showed variable values for the relative flow variation, water emission uniformity and relative flow rate coefficients, but no emitter was obstructed. Therefore, the current emitter design could be suitable for SDI following further studies to develop a final prototype.

OOPS! (OntOlogy Pitfall Scanner!): a web-based tool for ontology evaluation

Presentación en Workshop EUON 2014

Low-Cost Radar-Based Target Identification Prototype using an Expert System

Smart and green cities are hot topics in current research because people are becoming more conscious about their impact on the environment and the sustainability of their cities as the population increases. Many researchers are searching for mechanisms that can reduce power consumption and pollution in the city environment. This paper addresses the issue of public lighting and how it can be improved in order to achieve a more energy efficient city. This work is focused on making the process of turning the streetlights on and off more intelligent so that they consume less power and cause less light pollution. The proposed solution is comprised of a radar device and an expert system implemented on a low-cost platform based on a DSP. By analyzing the radar echo in both the frequency and time domains, the system is able to detect and identify objects moving in front of it. This information is used to decide whether or not the streetlight should be turned on. Experimental results show that the proposed system can provide hit rates over 80%, promising a good performance. In addition, the proposed solution could be useful in kind of other applications such as intelligent security and surveillance systems and home automation.

Contribución a la caracterización espacial de canales con sistemas MIMO-OFDM en la banda de 2,45 Ghz

La tecnología de múltiples antenas ha evolucionado para dar soporte a los actuales y futuros sistemas de comunicaciones inalámbricas en su afán por proporcionar la calidad de señal y las altas tasas de transmisión que demandan los nuevos servicios de voz, datos y multimedia. Sin embargo, es fundamental comprender las características espaciales del canal radio, ya que son las características del propio canal lo que limita en gran medida las prestaciones de los sistemas de comunicación actuales. Por ello surge la necesidad de estudiar la estructura espacial del canal de propagación para poder diseñar, evaluar e implementar de forma más eficiente tecnologías multiantena en los actuales y futuros sistemas de comunicación inalámbrica. Las tecnologías multiantena denominadas antenas inteligentes y MIMO han generado un gran interés en el área de comunicaciones inalámbricas, por ejemplo los sistemas de telefonía celular o más recientemente en las redes WLAN (Wireless Local Area Network), principalmente por la mejora que proporcionan en la calidad de las señales y en la tasa de transmisión de datos, respectivamente. Las ventajas de estas tecnologías se fundamentan en el uso de la dimensión espacial para obtener ganancia por diversidad espacial, como ya sucediera con las tecnologías FDMA (Frequency Division Multiplexing Access), TDMA (Time Division Multiplexing Access) y CDMA (Code Division Multiplexing Access) para obtener diversidad en las dimensiones de frecuencia, tiempo y código, respectivamente. Esta Tesis se centra en estudiar las características espaciales del canal con sistemas de múltiples antenas mediante la estimación de los perfiles de ángulos de llegada (DoA, Direction-of- Arrival) considerando esquemas de diversidad en espacio, polarización y frecuencia. Como primer paso se realiza una revisión de los sistemas con antenas inteligentes y los sistemas MIMO, describiendo con detalle la base matemática que sustenta las prestaciones ofrecidas por estos sistemas. Posteriormente se aportan distintos estudios sobre la estimación de los perfiles de DoA de canales radio con sistemas multiantena evaluando distintos aspectos de antenas, algoritmos de estimación, esquemas de polarización, campo lejano y campo cercano de las fuentes. Así mismo, se presenta un prototipo de medida MIMO-OFDM-SPAA3D en la banda ISM (Industrial, Scientific and Medical) de 2,45 Ghz, el cual está preparado para caracterizar experimentalmente el rendimiento de los sistemas MIMO, y para caracterizar espacialmente canales de propagación, considerando los esquemas de diversidad espacial, por polarización y frecuencia. Los estudios aportados se describen a continuación. Los sistemas de antenas inteligentes dependen en gran medida de la posición de los usuarios. Estos sistemas están equipados con arrays de antenas, los cuales aportan la diversidad espacial necesaria para obtener una representación espacial fidedigna del canal radio a través de los perfiles de DoA (DoA, Direction-of-Arrival) y por tanto, la posición de las fuentes de señal. Sin embargo, los errores de fabricación de arrays así como ciertos parámetros de señal conlleva un efecto negativo en las prestaciones de estos sistemas. Por ello se plantea un modelo de señal parametrizado que permite estudiar la influencia que tienen estos factores sobre los errores de estimación de DoA, tanto en acimut como en elevación, utilizando los algoritmos de estimación de DOA más conocidos en la literatura. A partir de las curvas de error, se pueden obtener parámetros de diseño para sistemas de localización basados en arrays. En un segundo estudio se evalúan esquemas de diversidad por polarización con los sistemas multiantena para mejorar la estimación de los perfiles de DoA en canales que presentan pérdidas por despolarización. Para ello se desarrolla un modelo de señal en array con sensibilidad de polarización que toma en cuenta el campo electromagnético de ondas planas. Se realizan simulaciones MC del modelo para estudiar el efecto de la orientación de la polarización como el número de polarizaciones usadas en el transmisor como en el receptor sobre la precisión en la estimación de los perfiles de DoA observados en el receptor. Además, se presentan los perfiles DoA obtenidos en escenarios quasiestáticos de interior con un prototipo de medida MIMO 4x4 de banda estrecha en la banda de 2,45 GHz, los cuales muestran gran fidelidad con el escenario real. Para la obtención de los perfiles DoA se propone un método basado en arrays virtuales, validado con los datos de simulación y los datos experimentales. Con relación a la localización 3D de fuentes en campo cercano (zona de Fresnel), se presenta un tercer estudio para obtener con gran exactitud la estructura espacial del canal de propagación en entornos de interior controlados (en cámara anecóica) utilizando arrays virtuales. El estudio analiza la influencia del tamaño del array y el diagrama de radiación en la estimación de los parámetros de localización proponiendo, para ello, un modelo de señal basado en un vector de enfoque de onda esférico (SWSV). Al aumentar el número de antenas del array se consigue reducir el error RMS de estimación y mejorar sustancialmente la representación espacial del canal. La estimación de los parámetros de localización se lleva a cabo con un nuevo método de búsqueda multinivel adaptativo, propuesto con el fin de reducir drásticamente el tiempo de procesado que demandan otros algoritmos multivariable basados en subespacios, como el MUSIC, a costa de incrementar los requisitos de memoria. Las simulaciones del modelo arrojan resultados que son validados con resultados experimentales y comparados con el límite de Cramer Rao en términos del error cuadrático medio. La compensación del diagrama de radiación acerca sustancialmente la exactitud de estimación de la distancia al límite de Cramer Rao. Finalmente, es igual de importante la evaluación teórica como experimental de las prestaciones de los sistemas MIMO-OFDM. Por ello, se presenta el diseño e implementación de un prototipo de medida MIMO-OFDM-SPAA3D autocalibrado con sistema de posicionamiento de antena automático en la banda de 2,45 Ghz con capacidad para evaluar la capacidad de los sistemas MIMO. Además, tiene la capacidad de caracterizar espacialmente canales MIMO, incorporando para ello una etapa de autocalibración para medir la respuesta en frecuencia de los transmisores y receptores de RF, y así poder caracterizar la respuesta de fase del canal con mayor precisión. Este sistema incorpora un posicionador de antena automático 3D (SPAA3D) basado en un scanner con 3 brazos mecánicos sobre los que se desplaza un posicionador de antena de forma independiente, controlado desde un PC. Este posicionador permite obtener una gran cantidad de mediciones del canal en regiones locales, lo cual favorece la caracterización estadística de los parámetros del sistema MIMO. Con este prototipo se realizan varias campañas de medida para evaluar el canal MIMO en términos de capacidad comparando 2 esquemas de polarización y tomando en cuenta la diversidad en frecuencia aportada por la modulación OFDM en distintos escenarios. ABSTRACT Multiple-antennas technologies have been evolved to be the support of the actual and future wireless communication systems in its way to provide the high quality and high data rates required by new data, voice and data services. However, it is important to understand the behavior of the spatial characteristics of the radio channel, since the channel by itself limits the performance of the actual wireless communications systems. This drawback raises the need to understand the spatial structure of the propagation channel in order to design, assess, and develop more efficient multiantenna technologies for the actual and future wireless communications systems. Multiantenna technologies such as ‘Smart Antennas’ and MIMO systems have generated great interest in the field of wireless communications, i.e. cellular communications systems and more recently WLAN (Wireless Local Area Networks), mainly because the higher quality and the high data rate they are able to provide. Their technological benefits are based on the exploitation of the spatial diversity provided by the use of multiple antennas as happened in the past with some multiaccess technologies such as FDMA (Frequency Division Multiplexing Access), TDMA (Time Division Multiplexing Access), and CDMA (Code Division Multiplexing Access), which give diversity in the domains of frequency, time and code, respectively. This Thesis is mainly focus to study the spatial channel characteristics using schemes of multiple antennas considering several diversity schemes such as space, polarization, and frequency. The spatial characteristics will be study in terms of the direction-of-arrival profiles viewed at the receiver side of the radio link. The first step is to do a review of the smart antennas and MIMO systems technologies highlighting their advantages and drawbacks from a mathematical point of view. In the second step, a set of studies concerning the spatial characterization of the radio channel through the DoA profiles are addressed. The performance of several DoA estimation methods is assessed considering several aspects regarding antenna array structure, polarization diversity, and far-field and near-field conditions. Most of the results of these studies come from simulations of data models and measurements with real multiantena prototypes. In the same way, having understand the importance of validate the theoretical data models with experimental results, a 2,4 GHz MIMO-OFDM-SPAA2D prototype is presented. This prototype is intended for evaluating MIMO-OFDM capacity in indoor and outdoor scenarios, characterize the spatial structure of radio channels, assess several diversity schemes such as polarization, space, and frequency diversity, among others aspects. The studies reported are briefly described below. As is stated in Chapter two, the determination of user position is a fundamental task to be resolved for the smart antenna systems. As these systems are equipped with antenna arrays, they can provide the enough spatial diversity to accurately draw the spatial characterization of the radio channel through the DoA profiles, and therefore the source location. However, certain real implementation factors related to antenna errors, signals, and receivers will certainly reduce the performance of such direction finding systems. In that sense, a parameterized narrowband signal model is proposed to evaluate the influence of these factors in the location parameter estimation through extensive MC simulations. The results obtained from several DoA algorithms may be useful to extract some parameter design for directing finding systems based on arrays. The second study goes through the importance that polarization schemes can have for estimating far-field DoA profiles in radio channels, particularly for scenarios that may introduce polarization losses. For this purpose, a narrowband signal model with polarization sensibility is developed to conduct an analysis of several polarization schemes at transmitter (TX) and receiver (RX) through extensive MC simulations. In addition, spatial characterization of quasistatic indoor scenarios is also carried out using a 2.45 GHz MIMO prototype equipped with single and dual-polarized antennas. A good agreement between the measured DoA profiles with the propagation scenario is achieved. The theoretical and experimental evaluation of polarization schemes is performed using virtual arrays. In that case, a DoA estimation method is proposed based on adding an phase reference to properly track the DoA, which shows good results. In the third study, the special case of near-field source localization with virtual arrays is addressed. Most of DoA estimation algorithms are focused in far-field source localization where the radiated wavefronts are assume to be planar waves at the receive array. However, when source are located close to the array, the assumption of plane waves is no longer valid as the wavefronts exhibit a spherical behavior along the array. Thus, a faster and effective method of azimuth, elevation angles-of-arrival, and range estimation for near-field sources is proposed. The efficacy of the proposed method is evaluated with simulation and validated with measurements collected from a measurement campaign carried out in a controlled propagation environment, i.e. anechoic chamber. Moreover, the performance of the method is assessed in terms of the RMSE for several array sizes, several source positions, and taking into account the effect of radiation pattern. In general, better results are obtained with larger array and larger source distances. The effect of the antennas is included in the data model leading to more accurate results, particularly for range rather than for angle estimation. Moreover, a new multivariable searching method based on the MUSIC algorithm, called MUSA (multilevel MUSIC-based algorithm), is presented. This method is proposed to estimate the 3D location parameters in a faster way than other multivariable algorithms, such as MUSIC algorithm, at the cost of increasing the memory size. Finally, in the last chapter, a MIMO-OFDM-SPAA3D prototype is presented to experimentally evaluate different MIMO schemes regarding antennas, polarization, and frequency in different indoor and outdoor scenarios. The prototype has been developed on a Software-Defined Radio (SDR) platform. It allows taking measurements where future wireless systems will be developed. The novelty of this prototype is concerning the following 2 subsystems. The first one is the tridimensional (3D) antenna positioning system (SPAA3D) based on three linear scanners which is developed for making automatic testing possible reducing errors of the antenna array positioning. A set of software has been developed for research works such as MIMO channel characterization, MIMO capacity, OFDM synchronization, and so on. The second subsystem is the RF autocalibration module at the TX and RX. This subsystem allows to properly tracking the spatial structure of indoor and outdoor channels in terms of DoA profiles. Some results are draw regarding performance of MIMO-OFDM systems with different polarization schemes and different propagation environments.

A voltage disturbances prototype for testing electrical generators connected to microgrids

The search for new energy models arises as a necessity to have a sustainable power supply. The inclusion of distributed generation sources (DG) allows to reduce the cost of facilities, increase the security of the grid or alleviate problems of congestion through the redistribution of power flows. In remote microgrids it is needed in a particular way a safe and reliable supply, which can cover the demand for a low cost; due to this, distributed generation is an alternative that is being widely introduced in these grids. But the remote microgrids are especially weak grids because of their small size, low voltage level, reduced network mesh and distribution lines with a high ratio R/X. This ratio affects the coupling between grid voltages and phase shifts, and stability becomes an issue of greater importance than in interconnected systems. To ensure the appropriate behavior of generation sources inserted in remote microgrids -and, in general, any electrical equipment-, it is essential to have devices for testing and certification. These devices must, not only faithfully reproduce disturbances occurring in remote microgrids, but also to behave against the equipment under test (EUT) as a real weak grid. This also makes the device commercially competitive. To meet these objectives and based on the aforementioned, it has been designed, built and tested a voltage disturbances generator, in order to provide a simple, versatile, full and easily scalable device to manufacturers and laboratories in the sector.

Development of a full hybrid lighting-CPV prototype and savings in a real case operation

A full Hybrid lighting-CPV prototype has been assembled. This new concept mixes a classical CPV module with the production of light for illumination without a double conversion (solar energy to electricity and electricity to light) allowing a higher efficiency to the whole system. The present prototype is based on a commercial CPV module that has been adapted in order to be hybrid, adjusting the receivers to pass the fibers into the module, inserting a holder to adjust x,y and z position of the fibers and changing the original parquet of lenses by a bifocal one composed most of the original lenses and the inclusion of other lenses in the position of the corners. Results show that with a minimal loss in the CPV part, a luminous flux is obtained that can be used to illuminate. Adding an additional electrical lamp and a light sensor that enables this lamp when no light from the sun is received, a 38% saving on lighting electricity is expected in Madrid during a year.

De la isla de Menorca a las costas sur y este de Inglaterra: análisis del prototipo de torre Martello = From the island of Minorca to the south and east coasts of England: analysis of the prototype of the Martello tower

Esta tesis doctoral desarrolla una investigación original sobre las torres defensivas de Menorca y las torres Martello de las costas sur y este de Inglaterra. Con respecto a las torres menorquinas, se distinguen las de Alcaufar y Punta Prima, construidas por ingenieros militares españoles, en 1786; de las levantadas por el ejército británico durante su último periodo de dominación de la isla, entre 1798 y 1802. Estos ingenieros reales británicos construyen las torres Martello en las costas inglesas, entre 1805 y 1812; y otras, semejantes a ellas, en el resto de su Imperio, hasta mediados del siglo XIX. La falta de estudios que relacionen las torres defensivas de Menorca y las Martello inglesas dentro del marco disciplinario de la construcción, ha constituido la justificación de esta investigación. La hipótesis de trabajo plantea un objetivo principal: el estudio y análisis comparativo entre ellas, que se desarrolla en varios niveles de análisis: morfológico, físico-constructivo, de visibilidades; pero también territorial, histórico y poliorcético. Esta tesis cuestiona, en consecuencia, la idea tradicionalmente aceptada de que las torres Martello tomaran la torre de Mortella, en Córcega, o cualquiera de las denominadas torres "preMartello", como referencia para crear su prototipo. La metodología empleada combina los trabajos de gabinete con una intensa labor de campo, en la que se documentaron cincuenta y siete torres, catorce en Menorca y cuarenta y tres en Inglaterra. Se han redactado sus correspondientes fichas de datos, que incluyen aspectos generales - morfológicos y constructivos -, así como documentación fotográfica. Se han elaborado los levantamientos morfológicos de siete de estas torres, aquellas que por sus particularidades constructivas, o bien representan un determinado tipo de torre, o bien se distinguen del resto. Del mismo modo, se han desarrollado los levantamientos físico-constructivos y la caracterización de materiales de las cuatro torres más relevantes para este estudio: las menorquinas Alcaufar y Punta Prima, y las torres 24 y C, que ejemplifican, respectivamente, las levantadas en las costas sur y este de Inglaterra. El sistemático método de trabajo llevado a cabo ha favorecido la investigación y ha ayudado a obtener conclusiones que verifican la hipótesis planteada en la tesis y cumplen los objetivos establecidos al comienzo de la misma. ABSTRACT This doctoral thesis develops an original research on the defensive towers of Minorca, and the Martello towers on the south and east coasts of England. Regarding the Minorcan towers, Alcaufar and Punta Prima, built by the Spanish military engineers in 1786, must be distinguished from those erected by the British Army during its last period of domination of the island between 1798 and 1802. These Royal Engineers build the Martello towers on the English coasts between 1805 and 1812; and others, similar to them, in the rest of their Empire until the middle of the 19th century. The lack of studies linking these Minorcan and English towers, within the disciplinary framework of construction, has been the justification for this research. The hypothesis poses a main goal: the study and comparative analysis of them, which takes place at several levels of analysis: morphological, constructive, of visibilities; but also territorial, historical and poliorcetic. Consequently, this thesis questions the traditionally accepted notion that the Martello towers took the Corsican Mortella Tower, or any of the so-called “preMartello” towers as a reference to create their prototype. The methodology combines the cabinet works with significant fieldwork, in which fifty seven towers were documented, fourteen in Minorca and forty three in England. The corresponding data sheets were drafted including general aspects - morphological and constructive-, and photographic documentation. Morphological survey plans were developed for seven of these towers due to their construction peculiarities, which either denote a specific type of tower or makes it stand out from the rest. Likewise, constructive survey plans and material characterisation sheets of the four more relevant towers in this study were developed: the Minorcan Alcaufar and Punta Prima, and towers 24 and C, both respectively exemplifying those built on the south and east coasts of England. The systematic method of work encouraged the research and helped to draw conclusions that both confirm the hypothesis raised in the thesis and meet the objectives established at the beginning of it.