Ballistic performance of nanocrystalline and nanotwinned ultrafine crystal steel

Because of their remarkable mechanical properties, nanocrystalline metals have been the focus of much research in recent years. Refining their grain size to the nanometer range (<100 nm) effectively reduces their dislocation mobility, thus achieving very high yield strength and surface hardness—as predicted by the Hall–Petch relation—as well as higher strain-rate sensitivity. Recent works have additionally suggested that nanocrystalline metals exhibit an even higher compressive strength under shock loading. However, the increase in strength of these materials is generally accompanied by an important reduction in ductility. As an alternative, efforts have been focused on ultrafine crystals, i.e. polycrystals with a grain size in the range of 500 nm to 1 μm, in which “growth twins” (twins introduced inside the grain before deformation) act as barriers against dislocation movement, thus increasing the strength in a similar way as nanocrystals but without significant loss of ductility. Due to their outstanding mechanical properties, both nanocrystalline and nanotwinned ultrafine crystalline steels appear to be relevant candidates for ballistic protection. The aim of the present work is to compare their ballistic performance against coarse-grained steel, as well as to identify the effect of the hybridization with a carbon fiber–epoxy composite layer. Hybridization is proposed as a way to improve the nanocrystalline brittle properties in a similar way as is done with ceramics in other protection systems. The experimental campaign is finally complemented by numerical simulations to help identify some of the intrinsic deformation mechanisms not observable experimentally. As a conclusion, nanocrystalline and nanotwinned ultrafine crystals show a lower energy absorption than coarse-grained steel under ballistic loading, but under equal impact conditions with no penetration, deformation in the impact direction is smaller by nearly 40%. This a priori surprising difference in the energy absorption is rationalized by the more important local contribution of the deviatoric stress vs. volumetric stress under impact than under uniaxial deformation. Ultimately, the deformation advantage could be exploited in the future for personal protection systems where a small deformation under impact is of key importance.

Non invasive moisture measurement in agricultural fiel using a rolling spherical robot

Irrigation management in large crop fields is a very important practice. Since the farm management costs and the crop results are directly connected with the environmental moisture, water control optimization is a critical factor for agricultural practices, as well as for the planet sustainability. Usually, the crop humidity is measured through the water stress index (WSI), using imagery acquired from satellites or airplanes. Nevertheless, these tools have a significant cost, lack from availability, and dependability from the weather. Other alternative is to recover to ground tools, such as ground vehicles and even static base stations. However, they have an outstanding impact in the farming process, since they can damage the cultivation and require more human effort. As a possible solution to these issues, a rolling ground robot have been designed and developed, enabling non-invasive measurements within crop fields. This paper addresses the spherical robot system applied to intra-crop moisture measurements. Furthermore, some experiments were carried out in an early stage corn field in order to build a geo-referenced WSI map.

Land use modelling and the role of stakeholders in natural protected areas: the case of Doñana national park, Spain

Doñana, a National Park since 1969, a UNESCO site since 1994 among other protected area designations of national and international character, is a coastal dune and marshland ecosystem of outstanding importance for biodiversity and conservation at the mouth of the Guadalaquivir River, Southwest Spain. However, the Doñana natural area is seriously threatened by global change factors such as humanly induced climate change, habitat loss, overexploitation of ecosystem services, and pollution. Not all stakeholders are convinced of the benefits of the national park, and management of Doñana, its environs and watershed are the subject of intense disagreement. This interplay between natural characteristics of great value with intense human pressure makes Doñana a fascinating workshop for the study of global human environment interactions. Here, we discuss the role of stakeholders in the application of a cellular automatabased model to Doñana and its environs and present the results of a series of exercises undertaken with stakeholders to parametrize the model, something often done by researchers without stakeholder engagement. By engaging with stakeholders early in the project, feedback generated from workshops contributes to model development. Stakeholders are therefore contributors of empirical data for the model as well as independent evaluators providing local and specialist knowledge.

VOTESCRIPT: Telematic voting system designed to enable final count verification

In this paper we present a global description of a telematic voting system based on advanced cryptography and on the use of smart cards (VOTESCRIPT system) whose most outstanding characteristic is the ability to verify that the tally carried out by the system is correct, meaning that the results published by the system correspond with votes cast. The VOTESCRIPT system provides an individual verification mechanism allowing each Voter to confirm whether his vote has been correctly counted. The innovation with respect to other solutions lies in the fact that the verification process is private so that Voters have no way of proving what they voted in the presence of a non-authorized third party. Vote buying and selling or any other kind of extortion are prevented. The existence of the Intervention Systems allows the whole electoral process to be controlled by groups of citizens or authorized candidatures. In addition to this the system can simply make an audit not only of the final results, but also of the whole process. Global verification provides the Scrutineers with robust cryptographic evidence which enables unequivocal proof if the system has operated in a fraudulent way.

The Dome-Shaped Fresnel-Köhler Concentrator

Manufacturing tolerances, along with a high concentration ratio, are key issues in order to obtain cheap CPV systems for mass production. Consequently, this manuscript presents a novel tolerant and cost effective concentrator optic: the domed-shaped Fresnel-Köhler, presenting a curved Fresnel lens as Primary Optical Element (POE). This concentrator is based on two previous successful CPV designs: the FK concentrator, based on a flat Fresnel lens, and the dome-shaped Fresnel lens system developed by Daido Steel, resulting on a superior concentrator. The manuscript shows outstanding simulation results for geometrical concentration factor of Cg? = ?1,230x: high tolerance and high optical efficiency, achieving acceptance angles of 1.18° (dealing to a CAP?=0.72) and efficiencies over 85% (without any anti-reflective coating). Moreover, Köhler integration provides good irradiance uniformity on the cell surface without increasing system complexity by means of any extra element. Daido Steel advanced technique for demolding injected plastic pieces will allow for easy manufacture of the dome-shaped POE of DFK concentrator.

Photovoltaic performance of the dome-shaped Fresnel-Köhler concentrator

In order to have a cost-effective CPV system, two key issues must be ensured: high concentration factor and high tolerance. The novel concentrator we are presenting, the dome-shaped Fresnel-Köhler, can widely fulfill these two and other essential issues in a CPV module. This concentrator is based on two previous successful CPV designs: the FK concentrator with a flat Fresnel lens and the dome-shaped Fresnel lens system developed by Daido Steel, resulting on a superior concentrator. The concentrator has shown outstanding simulation results, achieving an effective concentration-acceptance product (CAP) value of 0.72, and an optical efficiency of 85% on-axis (no anti-reflective coating has been used). Moreover, Köhler integration provides good irradiance uniformity on the cell surface and low spectral aberration of this irradiance. This ensures an optimal performance of the solar cell, maximizing its efficiency. Besides, the dome-shaped FK shows optimal results for very compact designs, especially in the f/0.7-1.0 range. The dome-shaped Fresnel-Köhler concentrator, natural and enhanced evolution of the flat FK concentrator, is a cost-effective CPV optical design, mainly due to its high tolerances. Daido Steel advanced technique for demolding injected plastic pieces will allow for easy manufacture of the dome-shaped POE of DFK concentrator.

Dome-shaped Fresnel-Köhler: a novel high performance optical concentrator

The dome-shaped Fresnel-Köhler concentrator is a novel optical design for photovoltaic applications. It is based on two previous successful CPV optical designs: the FK concentrator with a flat Fresnel lens and the dome-shaped Fresnel lens system developed by Daido Steel, resulting on a superior concentrator. This optical concentrator will be able to achieve large concentration factors, high tolerance (i.e. acceptance angle) and high optical efficiency, three key issues when dealing with photovoltaic applications. Besides, its irradiance is distributed on the cell surface in a very even way. The concentrator has shown outstanding simulation results, achieving an effective concentration-acceptance product (CAP) value of 0.72, on-axis optical efficiency over 85% and good irradiance uniformity on the cell provided by Köhler integration. Furthermore, due to its high tolerance, we will present the dome-shaped Fresnel-Köhler concentrator as a cost-effective CPV optical design. All this makes this concentrator superior to other conventional competitors in the current market.

Güímar and La Orotava mega-landslides (Tenerife) and tsunamis deposits in Canary Islands

More than 20 mega-landslides have been described in the Canary Islands affecting the flanks of the volcanic edifices. Gliimar and La Orotava landslides, in Tenerife, are two exceptional cases due to their huge dimensions and outstanding geomorphological features. The estimated volume of these landslides exceed tens of cubic km. Tsunami deposits have been also identified in some of the islands of the archipelago probably associated to the large landslides of the islands flanks. An investigation has been carried out to explain the causes of these large instability processes and their failure mechanisms. One of the main aspects investigated was the geomechanical characteristics of the volcanic rock masses, specially the hyaloclastite rocks forming the substratum underlying the emerged volcanic building. The low strength and high deformability properties of these rocks have played a fundamental role on the stability of the island flanks. The results have shown the gravitational origin of these instability processes as the main failure mechanism. Volcanic eruptions or large earthquakes could be contributing factors to the instability, but according with the data obtained in Gliimar and La Orotava cases they are not necessary as triggering factors. As a result of the field work carried out in the frame of the project, three large tsunami deposits have been identified in the islands of Lanzarote, Tenerifc and Gran Canaria attributed to rnega-Iandslides, possibly related to Guimar and La Orotava. A Sumrnary of their main features is described.

La evolución del paisaje fluvial en la confluencia de los ríos Tajo y Jarama

La tesis doctoral que se presenta realiza un análisis de la evolución del paisaje fluvial de las riberas de los ríos Tajo y Jarama en el entorno de Aranjuez desde una perspectiva múltiple. Contempla y conjuga aspectos naturales, tales como los hidrológicos, geomorfológicos y ecológicos; también culturales, como la regulación hidrológica y la gestión del agua, las intervenciones en cauce y márgenes, la evolución de la propiedad y los cambios de usos del suelo, fundamentalmente. Este análisis ha permitido identificar el sistema de factores, dinámico y complejo, que ha creado este paisaje, así como las interrelaciones, conexiones, condicionantes y dependencias de los descriptores paisajísticos considerados. Por ejemplo, se han estudiado las relaciones cruzadas observadas entre dinámica fluvial-propiedad de la tierra-estado de conservación, cuestiones que hasta la fecha no habían sido tratadas, evaluadas o cuantificadas en otros trabajos dedicados a esta zona. La investigación se ha organizado en tres fases fundamentales que han dado lugar a los capítulos centrales del documento (capítulos 2, 3 y 4). En primer lugar, se ha realizado una caracterización de los factores, naturales y culturales, que organizan el paisaje de este territorio eminentemente fluvial (geomorfología, factores climáticos e hidrológicos, vegetación, propiedad de la tierra y elementos culturales de significación paisajística). A continuación, se ha realizado el estudio de la evolución del paisaje fluvial mediante el análisis de diversos elementos, previamente identificados y caracterizados. Para ello se han procesado imágenes aéreas correspondientes a cinco series temporales así como varios planos antiguos, obteniendo una amplia base de datos que se ha analizado estadísticamente. Finalmente, se han contrastado los resultados parciales obtenidos en los capítulos anteriores, lo que ha permitido identificar relaciones causales entre los factores que organizan el paisaje y la evolución de los elementos que lo constituyen. También, interconexiones entre factores o entre elementos. Este método de trabajo ha resultado muy útil para la comprensión del funcionamiento y evolución de un sistema complejo, como el paisaje de la vega de Aranjuez, un territorio con profundas y antiguas intervenciones culturales donde lo natural, en cualquier caso, siempre subyace. Es posible que la principal aportación de este trabajo, también su diferencia más destacada respecto a otros estudios de paisaje, haya sido mostrar una visión completa y exhaustiva de todos los factores que han intervenido en la conformación y evolución del paisaje fluvial, destacando las relaciones que se establecen entre ellos. Esta manera de proceder puede tener una interesante faceta aplicada, de tal manera que resulta un instrumento muy útil para el diseño de planes de gestión de este territorio fluvial. No en vano, una parte sustancial de la vega del Tajo-Jarama en Aranjuez es un Lugar de Importancia Comunitaria (LIC) y su posterior e ineludible declaración como Zona de Especial Conservación (ZEC) de la Red Natura 2000, de acuerdo con lo establecido en la Directiva 92/43/CE, exige la elaboración de un Plan de Gestión que, en gran medida, podría nutrirse de lo presentado, analizado e interpretado en este trabajo. En este sentido, conviene señalar la conciencia ya asumida de considerar, por su carácter integrador de la realidad territorial, el paisaje como elemento clave para la gestión adecuada de la naturaleza y el territorio. Por otra parte, se considera que los resultados de esta Tesis Doctoral permitirían plantear medidas para la puesta en valor de un paisaje sobresaliente, cuyos límites sobrepasan con creces los que en la actualidad conforman el Paisaje Cultural declarado por la UNESCO. En suma, el análisis de este espacio fluvial realizado con la profundidad y amplitud que permite el método de trabajo seguido puede utilizarse para el diseño de estrategias que dirijan la evolución de este territorio en una línea que garantice su conservación global en términos paisajísticos, patrimoniales y ecológicos, permitiendo además, de este modo, su uso equilibrado como recurso económico, cultural o educativo. This doctoral thesis shows an analysis of fluvial landscape evolution from multiple perspectives on the banks of Tagus and Jarama rivers, around Aranjuez. The thesis contemplates and combines natural features, such as hydrological, geomorphological and ecological features, as well as cultural features, like hydrological regulation and water management, interventions in channels and margins, changes in ownership and land use changes, mainly. This analysis has allowed to identify the factors system, dynamic and complex, that this landscape has created, as well as the interrelationships, connections, constraints and dependencies among considered landscape descriptors. For example, we have studied the relationships observed among fluvial dynamics- land ownership -conservation status, issues not addressed, assessed or quantified up to now in other works about this area. The research is organized into three major phases that led to the paper's central chapters (Chapters 2, 3 and 4). First, there has been a characterization of the factors, both natural and cultural, that organize the landscape of this predominantly fluvial area (geomorphology, climate and hydrological factors, vegetation, land and cultural elements of landscape significance). Then, it was made to study of fluvial landscape evolution by analyzing various elements previously identified and characterized. Aerial images were processed for five series and several old maps, obtaining an extensive database, that has been analyzed statistically. Finally, we have contrasted the partial results obtained in the previous chapters, making it possible to identify causal relationships between the factors that organize the landscape and the evolution of the elements that constitute it. This working method has been very useful for understanding the operation and evolution of a complex system, as the landscape of the Vega de Aranjuez, a territory with deep and ancient cultural interventions where anyway, nature feature always lies. It is possible that the main contribution of this work, also its most prominent difference compared with other studies of landscape, has been to show a complete and exhaustive view of all factors involved in the formation and evolution of the fluvial landscape, highlighting the relationships established among them. This approach could have an interesting applied facet, so that is a very useful tool for designing management plans on this river territory. Not surprisingly, a substantial part of the valley of the Tagus-Jarama in Aranjuez is a Site of Community Importance (SCI) and their subsequent and inevitable declaration as Special Area of Conservation (SAC) of the Natura 2000 network, in accordance with the provisions Directive 92/43/EC, requires the development of a management plan that largely could draw on what was presented, analyzed and interpreted in this paper. In this regard, it should be noted conscience and assumed to consider, on the inclusiveness of territorial reality, the landscape as a key element for the proper management of nature and territory. On the other hand, it is considered that the results of this thesis allow to propose measures for enhancement of outstanding scenery, which go well beyond the boundaries that currently the Cultural Landscape declared by UNESCO. In sum, the analysis of this river area made with the depth and breadth that enables working method can be used to design strategies that address the evolution of this territory in a line that guarantees global conservation landscape terms, heritage and ecological, also, allowing its use as a balancing economic, cultural or educational resource.

Ingeniería de la conservación: Investigación aplicada para la conservación de la fauna mediterránea amenazada

El ser humano nunca ha tenido una capacidad semejante a la actual para alterar el medio en el que vive. A través fundamentalmente de cambios en el uso del hábitat, alteración de los ciclos biogeoquímicos, cambio climático y presencia de especies invasoras, la tasa de extinción de especies se ha acelerado enormemente. Al crecer más rápido la población humana dentro de las áreas en las que se concentra una mayor biodiversidad (biodiversity hotspots), las tasas de transformación son mayores, por lo que dicha biodiversidad se encuentra más amenazada. Entre los principales 25 biodiversity hotspots globales se encuentra la cuenca mediterránea. Las afecciones a la biodiversidad hacen por tanto que en dicha cuenca mediterránea sea necesario poner en práctica iniciativas innovadoras para su conservación. Pero además de una cuidadosa selección, es necesario el seguimiento y la evaluación de la eficacia y la eficienca de dichas medidas, para comprobar su idoneidad y mejorarlas cuando sea posible. Esta es la tarea de la ingeniería de la conservación. Esta Memoria busca analizar y proponer mejoras en cuatro acciones experimentales de conservación de la biodiversidad que tienen un marco común, la conservación de especies subrogadas del monte mediterráneo. En concreto de cinco especies amenazadas: conejo de monte (Oryctolagus cuniculus, especie llave), águila imperial ibérica (Aquila adalberti), águila perdicera (Aquila fasciata), cigüeña negra (Ciconia nigra) y lince ibérico (Lynx pardinus), todas ellas especies paraguas y bandera. Casi todas estas especies se enfrentan a amenazas comunes, como son la pérdida de la calidad del hábitat, la mortalidad de origen humano, la escasez de alimento o la falta de eficiencia en las técnicas de seguimiento. Las acciones destinadas a revertir o minimizar estas amenazas han tenido un marco geográfico y ecológico común, 49 fincas privadas de monte mediterráneo situadas en 9 espacios de la Red Natura 2000 del centro-occidental peninsular, en las que se ha podido trabajar merced a acuerdos de custodia del territorio. Dichas actividades han sido financiadas casi por completo con cargo a fondos LIFE Naturaleza de la Comisión Europea. El presente documento contribuye a aportar el conocimiento científico imprescindible para mejorar la eficacia y eficiencia de las medidas técnicas de gestión y conservación: la ingeniería de la conservación. Como resultados más relevantes se pueden citar que la selección del conejo de las zonas sembradas aumenta con la presencia tanto de isletas de matorral como de refugios y resulta inferior en las zonas de matorral más cerrado; que la electrocución es una de las principales causas de mortalidad de las rapaces amenazadas, así como que se ha detectado que la mortalidad se concentra en determinadas zonas que deben ser prioritarias para su corrección y que éstas deben pasar por las modificaciones estructurales; que la selección de zonas de alimentación por parte de la cigüeña negra se ve afectada por numerosos factores y que una adecuada ubicación y gestión de las charcas para ganadería y caza mayor puede favorecer no sólo la alimentación de esta especie, sino suponer un lugar de cría para diversas especies de anfibios y peces autóctonos, en franco declive; finalmente, hay que destacar que la mejora en el seguimiento de las poblaciones de lince ibérico pasa por la incorporación de métodos de seguimiento novedosos, como las cámaras infrarrojas en letrinas, dada la capacidad de aprendizaje de la especie. Abstract Nowadays the human being has reached its top ability to exchange its environment. Mainly through habitat change, altering biogeochemical cycles, climatic change and alien species, global extinction rate has increased dramatically. Population increases faster in biodiversity hotspots, thus change rates are higher. Mediterranean basin is included within the 25 most valuable biodiversity hotspots. Affections on biodiversity turns necessary to develop innovative actions to maintain the most threatened species in this hotspot. But further than a careful selection and implementarion, survey and evaluation of those practices is necessary to check its suitability. Those are actions for the conservation engineering. This Memory looks for to analyze and to put forward improvements in four experimental biodiversity conservation actions with a common framework: conservation of surrogate Mediterranean species. Those actions were specifically directed to five threatened species: the European wild rabbit (Oryctolagus cuniculus, key species), Spanish imperial eagle (Aquila adalberti) and Bonelli’s eagle (Aquila fasciata, both of the umbrella and flagship species), black stork (Ciconia nigra, umbrella and flagship species) and the Iberian lynx (Lynx pardinus, umbrella and flagship species). Those species have common threats: habitat loss, maninduced mortality, food shortening and lack of surveying efficiency. Actions aimed to minimize those threats also had a common geographical frame: 49 privately owned states within 9 Natura 2000 areas in Southwestern Spain. Actions were developed through lands tewardship agreements, and were even wholly undertaken through European Commision LIFE’s fund. This document contributes to develop cientific knowledge necessary for increasing efficacy and efficiency for implementing technical measures devoted to conservation, the conservation engineering. One of the most outstanding result might be the necessity of including bushy islets or rabbit shelter within sowings when enhacing rabbit populations is the goal. Electrocution is one of the commonest man-induced death causes for raptors, especially for the threatened ones. Areas of concentration of this mortality have been detected, and when mitigation measures have been evaluated, only structural modifications had results. The black stork’s selection of feeding areas is influenced by several factors. An adequate location and management of livestock’s ponds can favour not only this species, but also creating new breeding places for amphibians and indigenous fish species, most of them in a sharp decline. Finally, improving the survey of the Iberian lynx might be achieved through implementing newly developed surveying systems, such as the infrared cameras in latrines.

Evaluación de la contribución y el impacto de las tecnologías del habla en la detección automática del Síndrome de la Apnea Obstructiva del Sueño = Contributions and impact assessment of speech technologies on the automatic detection of severe Obstructive Sleep Apnea syndrome

La presente Tesis analiza las posibilidades que ofrecen en la actualidad las tecnologías del habla para la detección de patologías clínicas asociadas a la vía aérea superior. El estudio del habla que tradicionalmente cubre tanto la producción como el proceso de transformación del mensaje y las señales involucradas, desde el emisor hasta alcanzar al receptor, ofrece una vía de estudio alternativa para estas patologías. El hecho de que la señal emitida no solo contiene este mensaje, sino también información acerca del locutor, ha motivado el desarrollo de sistemas orientados a la identificación y verificación de la identidad de los locutores. Estos trabajos han recibido recientemente un nuevo impulso, orientándose tanto hacia la caracterización de rasgos que son comunes a varios locutores, como a las diferencias existentes entre grabaciones de un mismo locutor. Los primeros resultan especialmente relevantes para esta Tesis dado que estos rasgos podrían evidenciar la presencia de características relacionadas con una cierta condición común a varios locutores, independiente de su identidad. Tal es el caso que se enfrenta en esta Tesis, donde los rasgos identificados se relacionarían con una de la patología particular y directamente vinculada con el sistema de físico de conformación del habla. El caso del Síndrome de Apneas Hipopneas durante el Sueno (SAHS) resulta paradigmático. Se trata de una patología con una elevada prevalencia mundo, que aumenta con la edad. Los pacientes de esta patología experimentan episodios de cese involuntario de la respiración durante el sueño, que se prolongan durante varios segundos y que se reproducen a lo largo de la noche impidiendo el correcto descanso. En el caso de la apnea obstructiva, estos episodios se deben a la imposibilidad de mantener un camino abierto a través de la vía aérea, de forma que el flujo de aire se ve interrumpido. En la actualidad, el diagnostico de estos pacientes se realiza a través de un estudio polisomnográfico, que se centra en el análisis de los episodios de apnea durante el sueño, requiriendo que el paciente permanezca en el hospital durante una noche. La complejidad y el elevado coste de estos procedimientos, unidos a las crecientes listas de espera, han evidenciado la necesidad de contar con técnicas rápidas de detección, que si bien podrían no obtener tasas tan elevadas, permitirían reorganizar las listas de espera en función del grado de severidad de la patología en cada paciente. Entre otros, los sistemas de diagnostico por imagen, así como la caracterización antropométrica de los pacientes, han evidenciado la existencia de patrones anatómicos que tendrían influencia directa sobre el habla. Los trabajos dedicados al estudio del SAHS en lo relativo a como esta afecta al habla han sido escasos y algunos de ellos incluso contradictorios. Sin embargo, desde finales de la década de 1980 se conoce la existencia de patrones específicos relativos a la articulación, la fonación y la resonancia. Sin embargo, su descripción resultaba difícilmente aprovechable a través de un sistema de reconocimiento automático, pero apuntaba la existencia de un nexo entre voz y SAHS. En los últimos anos las técnicas de procesado automático han permitido el desarrollo de sistemas automáticos que ya son capaces de identificar diferencias significativas en el habla de los pacientes del SAHS, y que los distinguen de los locutores sanos. Por contra, poco se conoce acerca de la conexión entre estos nuevos resultados, los sé que habían obtenido en el pasado y la patogénesis del SAHS. Esta Tesis continua la labor desarrollada en este ámbito considerando específicamente: el estudio de la forma en que el SAHS afecta el habla de los pacientes, la mejora en las tasas de clasificación automática y la combinación de la información obtenida con los predictores utilizados por los especialistas clínicos en sus evaluaciones preliminares. Las dos primeras tareas plantean problemas simbióticos, pero diferentes. Mientras el estudio de la conexión entre el SAHS y el habla requiere de modelos acotados que puedan ser interpretados con facilidad, los sistemas de reconocimiento se sirven de un elevado número de dimensiones para la caracterización y posterior identificación de patrones. Así, la primera tarea debe permitirnos avanzar en la segunda, al igual que la incorporación de los predictores utilizados por los especialistas clínicos. La Tesis aborda el estudio tanto del habla continua como del habla sostenida, con el fin de aprovechar las sinergias y diferencias existentes entre ambas. En el análisis del habla continua se tomo como punto de partida un esquema que ya fue evaluado con anterioridad, y sobre el cual se ha tratado la evaluación y optimización de la representación del habla, así como la caracterización de los patrones específicos asociados al SAHS. Ello ha evidenciado la conexión entre el SAHS y los elementos fundamentales de la señal de voz: los formantes. Los resultados obtenidos demuestran que el éxito de estos sistemas se debe, fundamentalmente, a la capacidad de estas representaciones para describir dichas componentes, obviando las dimensiones ruidosas o con poca capacidad discriminativa. El esquema resultante ofrece una tasa de error por debajo del 18%, sirviéndose de clasificadores notablemente menos complejos que los descritos en el estado del arte y de una única grabación de voz de corta duración. En relación a la conexión entre el SAHS y los patrones observados, fue necesario considerar las diferencias inter- e intra-grupo, centrándonos en la articulación característica del locutor, sustituyendo los complejos modelos de clasificación por el estudio de los promedios espectrales. El resultado apunta con claridad hacia ciertas regiones del eje de frecuencias, sugiriendo la existencia de un estrechamiento sistemático en la sección del tracto en la región de la orofaringe, ya prevista en la patogénesis de este síndrome. En cuanto al habla sostenida, se han reproducido los estudios realizados sobre el habla continua en grabaciones de la vocal /a/ sostenida. Los resultados son cualitativamente análogos a los anteriores, si bien en este caso las tasas de clasificación resultan ser más bajas. Con el objetivo de identificar el sentido de este resultado se reprodujo el estudio de los promedios espectrales y de la variabilidad inter e intra-grupo. Ambos estudios mostraron importantes diferencias con los anteriores que podrían explicar estos resultados. Sin embargo, el habla sostenida ofrece otras oportunidades al establecer un entorno controlado para el estudio de la fonación, que también había sido identificada como una fuente de información para la detección del SAHS. De su estudio se pudo observar que, en el conjunto de datos disponibles, no existen variaciones que pudieran asociarse fácilmente con la fonación. Únicamente aquellas dimensiones que describen la distribución de energía a lo largo del eje de frecuencia evidenciaron diferencias significativas, apuntando, una vez más, en la dirección de las resonancias espectrales. Analizados los resultados anteriores, la Tesis afronta la fusión de ambas fuentes de información en un único sistema de clasificación. Con ello es posible mejorar las tasas de clasificación, bajo la hipótesis de que la información presente en el habla continua y el habla sostenida es fundamentalmente distinta. Esta tarea se realizo a través de un sencillo esquema de fusión que obtuvo un 88.6% de aciertos en clasificación (tasa de error del 11.4%), lo que representa una mejora significativa respecto al estado del arte. Finalmente, la combinación de este clasificador con los predictores utilizados por los especialistas clínicos ofreció una tasa del 91.3% (tasa de error de 8.7%), que se encuentra dentro del margen ofrecido por esquemas más costosos e intrusivos, y que a diferencia del propuesto, no pueden ser utilizados en la evaluación previa de los pacientes. Con todo, la Tesis ofrece una visión clara sobre la relación entre el SAHS y el habla, evidenciando el grado de madurez alcanzado por la tecnología del habla en la caracterización y detección del SAHS, poniendo de manifiesto que su uso para la evaluación de los pacientes ya sería posible, y dejando la puerta abierta a futuras investigaciones que continúen el trabajo aquí iniciado. ABSTRACT This Thesis explores the potential of speech technologies for the detection of clinical disorders connected to the upper airway. The study of speech traditionally covers both the production process and post processing of the signals involved, from the speaker up to the listener, offering an alternative path to study these pathologies. The fact that utterances embed not just the encoded message but also information about the speaker, has motivated the development of automatic systems oriented to the identification and verificaton the speaker’s identity. These have recently been boosted and reoriented either towards the characterization of traits that are common to several speakers, or to the differences between records of the same speaker collected under different conditions. The first are particularly relevant to this Thesis as these patterns could reveal the presence of features that are related to a common condition shared among different speakers, regardless of their identity. Such is the case faced in this Thesis, where the traits identified would relate to a particular pathology, directly connected to the speech production system. The Obstructive Sleep Apnea syndrome (OSA) is a paradigmatic case for analysis. It is a disorder with high prevalence among adults and affecting a larger number of them as they grow older. Patients suffering from this disorder experience episodes of involuntary cessation of breath during sleep that may last a few seconds and reproduce throughout the night, preventing proper rest. In the case of obstructive apnea, these episodes are related to the collapse of the pharynx, which interrupts the air flow. Currently, OSA diagnosis is done through a polysomnographic study, which focuses on the analysis of apnea episodes during sleep, requiring the patient to stay at the hospital for the whole night. The complexity and high cost of the procedures involved, combined with the waiting lists, have evidenced the need for screening techniques, which perhaps would not achieve outstanding performance rates but would allow clinicians to reorganize these lists ranking patients according to the severity of their condition. Among others, imaging diagnosis and anthropometric characterization of patients have evidenced the existence of anatomical patterns related to OSA that have direct influence on speech. Contributions devoted to the study of how this disorder affects scpeech are scarce and somehow contradictory. However, since the late 1980s the existence of specific patterns related to articulation, phonation and resonance is known. By that time these descriptions were virtually useless when coming to the development of an automatic system, but pointed out the existence of a link between speech and OSA. In recent years automatic processing techniques have evolved and are now able to identify significant differences in the speech of OSAS patients when compared to records from healthy subjects. Nevertheless, little is known about the connection between these new results with those published in the past and the pathogenesis of the OSA syndrome. This Thesis is aimed to progress beyond the previous research done in this area by addressing: the study of how OSA affects patients’ speech, the enhancement of automatic OSA classification based on speech analysis, and its integration with the information embedded in the predictors generally used by clinicians in preliminary patients’ examination. The first two tasks, though may appear symbiotic at first, are quite different. While studying the connection between speech and OSA requires simple narrow models that can be easily interpreted, classification requires larger models including a large number dimensions for the characterization and posterior identification of the observed patterns. Anyhow, it is clear that any progress made in the first task should allow us to improve our performance on the second one, and that the incorporation of the predictors used by clinicians shall contribute in this same direction. The Thesis considers both continuous and sustained speech analysis, to exploit the synergies and differences between them. On continuous speech analysis, a conventional speech processing scheme, designed and evaluated before this Thesis, was taken as a baseline. Over this initial system several alternative representations of the speech information were proposed, optimized and tested to select those more suitable for the characterization of OSA-specific patterns. Evidences were found on the existence of a connection between OSA and the fundamental constituents of the speech: the formants. Experimental results proved that the success of the proposed solution is well explained by the ability of speech representations to describe these specific OSA-related components, ignoring the noisy ones as well those presenting low discrimination capabilities. The resulting scheme obtained a 18% error rate, on a classification scheme significantly less complex than those described in the literature and operating on a single speech record. Regarding the connection between OSA and the observed patterns, it was necessary to consider inter-and intra-group differences for this analysis, and to focus on the articulation, replacing the complex classification models by the long-term average spectra. Results clearly point to certain regions on the frequency axis, suggesting the existence of a systematic narrowing in the vocal tract section at the oropharynx. This was already described in the pathogenesis of this syndrome. Regarding sustained speech, similar experiments as those conducted on continuous speech were reproduced on sustained phonations of vowel / a /. Results were qualitatively similar to the previous ones, though in this case perfomance rates were found to be noticeably lower. Trying to derive further knowledge from this result, experiments on the long-term average spectra and intraand inter-group variability ratios were also reproduced on sustained speech records. Results on both experiments showed significant differences from the previous ones obtained from continuous speech which could explain the differences observed on peformance. However, sustained speech also provided the opportunity to study phonation within the controlled framework it provides. This was also identified in the literature as a source of information for the detection of OSA. In this study it was found that, for the available dataset, no sistematic differences related to phonation could be found between the two groups of speakers. Only those dimensions which relate energy distribution along the frequency axis provided significant differences, pointing once again towards the direction of resonant components. Once classification schemes on both continuous and sustained speech were developed, the Thesis addressed their combination into a single classification system. Under the assumption that the information in continuous and sustained speech is fundamentally different, it should be possible to successfully merge the two of them. This was tested through a simple fusion scheme which obtained a 88.6% correct classification (11.4% error rate), which represents a significant improvement over the state of the art. Finally, the combination of this classifier with the variables used by clinicians obtained a 91.3% accuracy (8.7% error rate). This is within the range of alternative, but costly and intrusive schemes, which unlike the one proposed can not be used in the preliminary assessment of patients’ condition. In the end, this Thesis has shed new light on the underlying connection between OSA and speech, and evidenced the degree of maturity reached by speech technology on OSA characterization and detection, leaving the door open for future research which shall continue in the multiple directions that have been pointed out and left as future work.

Optimización de la composición del hueco de fachada en materia de eficiencia energética. Propuesta de indicador como herramienta para el análisis integral del elemento acristalado = Energy performance optimization of window systems. Proposal of an indicator as a tool for an integrated analysis of glazing

La hipótesis de esta tesis es: "La optimización de la ventana considerando simultáneamente aspectos energéticos y aspectos relativos a la calidad ambiental interior (confort higrotérmico, lumínico y acústico) es compatible, siempre que se conozcan y consideren las sinergias existentes entre ellos desde las primeras fases de diseño". En la actualidad se desconocen las implicaciones de muchas de las decisiones tomadas en torno a la ventana; para que su eficiencia en relación a todos los aspectos mencionados pueda hacerse efectiva es necesaria una herramienta que aporte más información de la actualmente disponible en el proceso de diseño, permitiendo así la optimización integral, en función de las circunstancias específicas de cada proyecto. En la fase inicial de esta investigación se realiza un primer acercamiento al tema, a través del estado del arte de la ventana; analizando la normativa existente, los componentes, las prestaciones, los elementos experimentales y la investigación. Se observa que, en ocasiones, altos requisitos de eficiencia energética pueden suponer una disminución de las prestaciones del sistema en relación con la calidad ambiental interior, por lo que surge el interés por integrar al análisis energético aspectos relativos a la calidad ambiental interior, como son las prestaciones lumínicas y acústicas y la renovación de aire. En este punto se detecta la necesidad de realizar un estudio integral que incorpore los distintos aspectos y evaluar las sinergias que se dan entre las distintas prestaciones que cumple la ventana. Además, del análisis de las soluciones innovadoras y experimentales se observa la dificultad de determinar en qué medida dichas soluciones son eficientes, ya que son soluciones complejas, no caracterizadas y que no están incorporadas en las metodologías de cálculo o en las bases de datos de los programas de simulación. Por lo tanto, se plantea una segunda necesidad, generar una metodología experimental para llevar a cabo la caracterización y el análisis de la eficiencia de sistemas innovadores. Para abordar esta doble necesidad se plantea la optimización mediante una evaluación del elemento acristalado que integre la eficiencia energética y la calidad ambiental interior, combinando la investigación teórica y la investigación experimental. En el ámbito teórico, se realizan simulaciones, cálculos y recopilación de información de distintas tipologías de hueco, en relación con cada prestación de forma independiente (acústica, iluminación, ventilación). A pesar de haber partido con un enfoque integrador, resulta difícil esa integración detectándose una carencia de herramientas disponible. En el ámbito experimental se desarrolla una metodología para la evaluación del rendimiento y de aspectos ambientales de aplicación a elementos innovadores de difícil valoración mediante la metodología teórica. Esta evaluación consiste en el análisis comparativo experimental entre el elemento innovador y un elemento estándar; para llevar a cabo este análisis se han diseñado dos espacios iguales, que denominamos módulos de experimentación, en los que se han incorporado los dos sistemas; estos espacios se han monitorizado, obteniéndose datos de consumo, temperatura, iluminancia y humedad relativa. Se ha realizado una medición durante un periodo de nueve meses y se han analizado y comparado los resultados, obteniendo así el comportamiento real del sistema. Tras el análisis teórico y el experimental, y como consecuencia de esa necesidad de integrar el conocimiento existente se propone una herramienta de evaluación integral del elemento acristalado. El desarrollo de esta herramienta se realiza en base al procedimiento de diagnóstico de calidad ambiental interior (CAI) de acuerdo con la norma UNE 171330 “Calidad ambiental en interiores”, incorporando el factor de eficiencia energética. De la primera parte del proceso, la parte teórica y el estado del arte, se obtendrán los parámetros que son determinantes y los valores de referencia de dichos parámetros. En base a los parámetros relevantes obtenidos se da forma a la herramienta, que consiste en un indicador de producto para ventanas que integra todos los factores analizados y que se desarrolla según la Norma UNE 21929 “Sostenibilidad en construcción de edificios. Indicadores de sostenibilidad”. ABSTRACT The hypothesis of this thesis is: "The optimization of windows considering energy and indoor environmental quality issues simultaneously (hydrothermal comfort, lighting comfort, and acoustic comfort) is compatible, provided that the synergies between these issues are known and considered from the early stages of design ". The implications of many of the decisions made on this item are currently unclear. So that savings can be made, an effective tool is needed to provide more information during the design process than the currently available, thus enabling optimization of the system according to the specific circumstances of each project. The initial phase deals with the study from an energy efficiency point of view, performing a qualitative and quantitative analysis of commercial, innovative and experimental windows. It is observed that sometimes, high-energy efficiency requirements may mean a reduction in the system's performance in relation to user comfort and health, that's why there is an interest in performing an integrated analysis of indoor environment aspects and energy efficiency. At this point a need for a comprehensive study incorporating the different aspects is detected, to evaluate the synergies that exist between the various benefits that meet the window. Moreover, from the analysis of experimental and innovative windows, a difficulty in establishing to what extent these solutions are efficient is observed; therefore, there is a need to generate a methodology for performing the analysis of the efficiency of the systems. Therefore, a second need arises, to generate an experimental methodology to perform characterization and analysis of the efficiency of innovative systems. To address this dual need, the optimization of windows by an integrated evaluation arises, considering energy efficiency and indoor environmental quality, combining theoretical and experimental research. In the theoretical field, simulations and calculations are performed; also information about the different aspects of indoor environment (acoustics, lighting, ventilation) is gathered independently. Despite having started with an integrative approach, this integration is difficult detecting lack available tools. In the experimental field, a methodology for evaluating energy efficiency and indoor environment quality is developed, to be implemented in innovative elements which are difficult to evaluate using a theoretical methodology This evaluation is an experimental comparative analysis between an innovative element and a standard element. To carry out this analysis, two equal spaces, called experimental cells, have been designed. These cells have been monitored, obtaining consumption, temperature, luminance and relative humidity data. Measurement has been performed during nine months and results have been analyzed and compared, obtaining results of actual system behavior. To advance this optimization, windows have been studied from the point of view of energy performance and performance in relation to user comfort and health: thermal comfort, acoustic comfort, lighting comfort and air quality; proposing the development of a methodology for an integrated analysis including energy efficiency and indoor environment quality. After theoretical and experimental analysis and as a result of the need to integrate existing knowledge, a comprehensive evaluation procedure for windows is proposed. This evaluation procedure is developed according to the UNE 171330 "Indoor Environmental Quality", also incorporating energy efficiency and cost as factors to evaluate. From the first part of the research process, outstanding parameters are chosen and reference values of these parameters are set. Finally, based on the parameters obtained, an indicator is proposed as windows product indicator. The indicator integrates all factors analyzed and is developed according to ISO 21929-1:2011"Sustainability in building construction. Sustainability indicators. Part 1: Framework for the development of indicators and a core set of indicators for buildings".

Tres iglesias sajonas fortificadas en Transilvania, Rumanía: Hosman, Pelişor y Moşna

Saxon colonization in Transylvania occurred from 12th Century with the establishment of the populations with certain degree of freedom and autonomy. External threats over this territory obliged to the fortification of their churches, mainly between 15th and 16th Centuries with the advance of Turkish Empire. The fortification of the churches consists on the building of walls with gates and flanking towers, and also with the incorporation of several defensive elements over the apses. Most outstanding characteristics of this fortified system are the homogeneity in typology, construction and polyorcetic, without detracting of the singularity of each one of the more of 150 conserved churches. The article presents an actual state of the art. Also, it develops the main historical elements and it explains the architectonic typology and the constructive characteristics. At last, defensive elements are analyzed from the comparative and deep study through three proper examples: the churches of Hosman, Pelisor and Mosna. La colonización sajona de Transilvania se produjo a partir del siglo XII con el asentamiento de poblaciones con cierto grado de libertad y autonomía. Las amenazas externas sobre este territorio obligaron a la fortificación de sus iglesias, principalmente entre los siglos XV y XVI ante el avance del imperio turco. La fortificación de las iglesias consta de la construcción de murallas con puertas y torres de flanqueo, además de la incorporación de diversos elementos poliorcéticos sobre las cabeceras de las iglesias. Las características más relevantes de este sistema fortificado es la homogeneidad tipológica, constructiva y poliorcética sin menoscabo de la singularidad de cada una de las más de 150 iglesias conservadas. El artículo presenta un estado de la cuestión actualizado, además de desarrollar los elementos históricos más relevantes, explicar la tipología arquitectónica y las característica constructivas y analizar los elementos poliorcéticos desde el estudio comparado y profundo de tres ejemplos característicos: las iglesias de Hosman, Pelisor y Mosna.

Implementación y configuración de un receptor de radio definido por software (SDR) para estudios de propagación

The constant development of digital systems in radio communications demands the adaptation of the current receiving equipment to the new technologies. In this context, a new Software Defined Radio based receiver is being implemented with the aim of carrying out different experiments to analyze the propagation of signals through the atmosphere from a satellite beacon. The receiver selected for this task is the PERSEUS SDR from the Italian company Microtelecom s.r.l. It is a software defined VLF-LF-MF-HF receiver based on an outstanding direct sampling digital architecture which features a 14 bit 80 MSamples/s analog-to-digital converter, a high-performance FPGA-based digital down-converter and a high-speed 480 Mbit/s USB2.0 PC interface. The main goal is to implement the related software and adapt the new receiver to the current working environment. In this paper, SDR technology guidelines are given and PERSEUS receiver digital signal processing is presented with the most remarkable results.

Technology of bare tether current collection

The outstanding problem for useful applications of electrodynamic tethers is obtaining sufficient electron current from the ionospheric plasma. Bare tether collectors, in which the conducting tether itself, left uninsulated over kilometers of its length, acts as the collecting anode, promise to attain currents of 10 A or more from reasonably sized systems. Current collection by a bare tether is also relatively insensitive to drops in electron density, which are regularly encountered on each revolution of an orbit. This makes nighttime operation feasible. We show how the bare tether's high efficiency of current collection and ability to adjust to density variations follow from the orbital motion limited collection law of thin cylinders. We consider both upwardly deployed (power generation mode) and downwardly deployed (reboost mode) tethers, and present results that indicate how bare tether systems would perform as their magnetic and plasma environment varies in low earth orbit.