70 resultados para Mateo Sagasta
em Universidad Politécnica de Madrid
Resumo:
Speed enforcement on public roadways is an important issue in order to guarantee road security and to reduce the number and seriousness of traffic accidents. Traditionally, this task has been partially solved using radar and/or laser technologies and, more recently, using video-camera based systems. All these systems have significant shortcomings that have yet to be overcome. The main drawback of classical Doppler radar technology is that the velocity measurement fails when several vehicles are in the radars beam. Modern radar systems are able to measure speed and range between vehicle and radar. However, this is not enough to discriminate the lane where the vehicle is driving on. The limitation of several vehicles in the beam is overcome using laser technology. However, laser systems have another important limitation: They cannot measure the speed of several vehicles simultaneously. Novel video-camera systems, based on license plate identification, solve the previous drawbacks, but they have the problem that they can only measure average speed but never top-speed. This paper studies the feasibility of using an interferometric linear frequency modulated continuous wave radar to improve top-speed enforcement on roadways. Two different systems based on down-the-road and across-the-road radar configurations are presented. The main advantage of the proposed solutions is they can simultaneously measure speed, range, and lane of several vehicles, allowing the univocal identification of the offenders. A detailed analysis about the operation and accuracy of these solutions is reported. In addition, the feasibility of the proposed techniques has been demonstrated with simulations and real experiments using a Ka-band interferometric radar developed by our research group.
Resumo:
La elaboración de este estudio pretende caracterizar los accidentes causados por animales ocurridos en la Comunidad de Madrid entre el año 2006 y el 2009 mediante la identificación de zonas prioritarias de actuación con métodos de estadística espacial (análisis Hot Spot). Con ello se elabora a escala de paisaje un modelo predictivo de colisiones generado a partir de variables ambientales que determinan el desplazamiento de ungulados en el territorio, lo que a su vez influye en los cambios de uso del suelo.
Resumo:
Los paneles sándwich de madera son un producto de creciente aplicación en la edificación de nuestro país. Este ascendente uso del material debe estar acompañado de las garantías necesarias avaladas por un estudio previo de sus prestaciones. Como es preceptivo y entre otros, se evalúa su durabilidad frente a las condiciones climatológicas, clave en los productos derivados de la madera, acorde a la normativa actual definida con tal fin, la Guía ETAG 016. Sin embargo, debido a la clase de uso del material, se ha detectado que dicha normativa tal y como está concebida no es capaz de valorar su envejecimiento adecuadamente. En este trabajo se proponen ensayos alternativos al establecido tras exhaustivos aná- lisis que recrean las condiciones reales de uso y más acordes a los productos de madera. Se concluye que la incorporación de una lámina impermeable, pero permeable al vapor de agua hacia el exterior, como las utilizadas en el montaje, aportan el mejor procedimiento de ensayo. Composite lightweight wood panels are being increasingly used in construction in Spain. Their growing use should be accompanied by necessary guarantees based on studies of their properties. As it is prescriptive and in addition to others tests, in the present work is examinated the durability of these panels when exposed to the climatic conditions, a characteristic of great importance for wood products, according to Guide ETAG 016, the current standard defining the ageing tests to be used. However, due to the use class of this material, there are indications that the testing outlined in this Guide is inappropriate for assessing the ageing of wood-based sandwich panels. Alternative tests are here proposed that recreate rather better the real conditions under which these products are used. Covering the samples in a waterproof sheeting permeable to the outward movement of water vapour, which is in fact used in the installation, provided the best procedure for testing these panels.
Resumo:
Las recientes investigaciones realizadas en los potentes yacimientos de arcillas que se encuentran en la Ciudad de Malabo (Bioko Norte), República de Guinea Ecuatorial, revelaron la presencia mayoritaria de una fase compuesta por sepiolita, acompañada por especies secundarias de feldespato, caolinita, hematita, moscovita e illita. Los análisis por microscopía electrónica de barrido (MEB), difracción de rayos x (DRX) y agregado orientado con etilenglicol (AO), indican un comportamiento similar y homogéneo de la composición de las muestras estudiadas. Por otro lado, los análisis químicos, puzolanicidad, granulometría (tamizado en seco), consistencia, tiempo de inicio y final de fraguado y la determinación de la estabilidad de volumen, confirman la idoneidad de estas arcillas sepiolíticas no expansivas para sustituir hasta un 25% del cemento portland en los proyectos de mezclas de morteros. No se tiene noticia sobre la realización de proyectos de investigación en estas formaciones sedimentarias, por lo que se considera el primer trabajo de carácter científico que se inicia para la caracterización, sistematización y posibles aplicaciones de estas arcillas en la aún incipiente industria de la construcción ecuatoguineana.
Resumo:
PREDICT POTENTIAL DISTRIBUTION. Spatial and temporal evolution of the species under different climate scenarios. Generation of habitat suitability models (HSM) high degree of uncertainty and limitations. The importance of their validation has been stressed. In this work we discuss the present potential distribution of P. sylvestris and P. nigra in the Iberian Peninsula by using MaxEnt, and evaluate the influence of the different environmental variables. Our intention is to select a set of environmental variables that explains better their current distribution, to achieve the most accurate and reliable models. Then we project them to the past climatic conditions (21 to 0 kyrs BP), to evaluate the outputs with existing palaeo-ecological data.
Resumo:
Las gemas se evalúan mediante la norma de clasificación visual (UNE 56544), pero su aplicación en estructuras existentes y grandes escuadrías resulta poco eficaz y conduce a estimaciones demasiado conservadoras. Este trabajo analiza la influencia de las gemas comparando la resistencia de piezas con gemas y piezas correctamente escuadradas. Se han analizado 218 piezas de pino silvestre con dimensiones nominales 150 x 200 x 4.200 mm, de las que 102 presentaban una gema completa a lo largo de toda su longitud y el resto estaban correctamente escuadradas. En las piezas con gema se ha medido la altura de la sección cada 30 cm (altura en cada cara y altura máxima). Para determinar la resistencia se han ensayado todas las piezas de acuerdo a la norma EN 408. Se ha comparado la resistencia obtenida para las piezas con gema, diferenciando si la gema se encuentra en el borde comprimido o en el borde traccionado, con las piezas escuadradas. Puede concluirse que la presencia de gemas disminuye la resistencia excepto si la gema se encuentra en el borde traccionado, en cuyo caso los resultados obtenidos han sido similares a los de las piezas escuadradas. The wanes on structural timber are evaluated according to the visual grading standard (UNE 56544), but its application on existing structures and large cross sections is ineffective and leads to conservative estimations. This paper analyzes the influence of the wanes by comparing the resistance of pieces with wanes and square pieces. 218 pieces of Scotch pine with nominal dimensions 150 x 200 x 4200 mm have been analyzed, 102 of them had a complete wane along its length and the rest were properly squared. The height of the cross section was measured every 30 cm (the height on each side and the maximum height) for the pieces with wane. The bending strength of all the pieces was obtained according to the EN 408 standard. The bending strength of the pieces with wane has been compared with the strength of the squared pieces, taking into account if the wane is positioned on the compressed edge or on the tensioned edge. It can be concluded that the bending strength of the pieces with wanes is lower than the one of squared pieces, except if the wanes are on the tensioned edge of the beam.
Resumo:
Six-port network is an interesting radiofrequency architecture with multiple possibilities. Since it was firstly introduced in the seventies as an alternative network analyzer, the six-port network has been used for many applications, such as homodyne receivers, radar systems, direction of arrival estimation, UWB (Ultra-Wide-Band), or MIMO (Multiple Input Multiple Output) systems. Currently, it is considered as a one of the best candidates to implement a Software Defined Radio (SDR). This thesis comprises an exhaustive study of this promising architecture, where its fundamentals and the state-of-the-art are also included. In addition, the design and development of a SDR 0.3-6 GHz six-port receiver prototype is presented in this thesis, which is implemented in conventional technology. The system is experimentally characterized and validated for RF signal demodulation with good performance. The analysis of the six-port architecture is complemented by a theoretical and experimental comparison with other radiofrequency architectures suitable for SDR. Some novel contributions are introduced in the present thesis. Such novelties are in the direction of the highly topical issues on six-port technique: development and optimization of real-time I-Q regeneration techniques for multiport networks; and search of new techniques and technologies to contribute to the miniaturization of the six-port architecture. In particular, the novel contributions of this thesis can be summarized as: - Introduction of a new real-time auto-calibration method for multiport receivers, particularly suitable for broadband designs and high data rate applications. - Introduction of a new direct baseband I-Q regeneration technique for five-port receivers. - Contribution to the miniaturization of six-port receivers by the use of the multilayer LTCC (Low Temperature Cofired Ceramic) technology. Implementation of a compact (30x30x1.25 mm) broadband (0.3-6 GHz) six-port receiver in LTTC technology. The results and conclusions derived from this thesis have been satisfactory, and quite fruitful in terms of publications. A total of fourteen works have been published, considering international journals and conferences, and national conferences. Aditionally, a paper has been submitted to an internationally recognized journal, which is currently under review.
Resumo:
El principal objetivo de este estudio es evaluar la influencia de las fendas de secado en las propiedades mecánicas de vigas de madera. Para esto, se utilizan 40 vigas de Pino silvestre (Pinus sylvestris L) de 4200 mm de longitud y 150x200 mm de sección que fueron ensayadas según norma EN 408. Las fendas se registran detalladamente atendiendo a su longitud y posición en cada cara de la viga, y midiendo el espesor y la profundidad cada 100mm a lo largo de la viga. Solo el 10% de la muestra es rechazada por las fendas, según los criterios establecidos por la norma española de clasificación visual UNE 56544. Para evaluar la influencia de las fendas en las propiedades mecánicas, se usan tres parámetros globales basados en el área, el volumen o la profundad de la fenda, y dos locales basados en la profundidad máxima y la profundidad en la zona de rotura. Además se determina la densidad de las piezas. Estos parámetros se comparan con las propiedades mecánicas (tensión de rotura, módulo de elasticidad y energía de rotura) y se encuentra escasa relación entre ellos. Las mejores correlaciones se encuentran entre los parámetros relacionados con la profundidad de las fendas, tanto con el módulo de elasticidad como con la tensión de rotura. The aim of this study is the evaluation of the influence of drying fissures on the mechanical properties of timber beams. For that purpose, 40 sawn timber pieces of Scots pine (Pinus sylvestris L.) with 150x200 mm in cross-section and 4200 mm in length have been tested according to EN 408, obtaining MOR and MOE. The fissures were registered in detail measuring their length and position in each face of the beam, and the thickness and depth every 100 mm in length. Only 10 % of the pieces were rejected because fissures, according to UNE 56544 Spanish visual grading standard. To evaluate the influence of fissures in mechanical properties three global parameters: Fissures Area Ratio or ratio between the area occupied by fissures and the total area in the neutral axis plane of the beam; Fissures Volume Ratio or ratio between volume of fissures and the total volume of the beam; Fissures Average Depth and two local parameters were used: Fissures Maximum Depth in the beam, and Fissures Depth in the broken zone of the beam. Also the density of the beams was registered. These parameters were compared with mechanical properties (tensile strength, elasticity modulus, and rupture energy) and the relationship between them had not been founded. The best relationship was founded between the elasticity modulus y the tensile strength with the parameters which included the depth of the fissures.
Resumo:
Large cross section structural timber have been used in many structures over long periods of time and still make up an important part of the market due to its mechanical properties. Furthermore, it is frequent its employment in new construction site. It involves the need for a visual grading standard for timber used in construction according to the quality assessment. The material has to satisfy the requirements according to the currently regulations. UNE 56544 is the Spanish visual grading standard for coniferous structural timber. The 2007 version defined a new visual grade in the standard for large section termed Structural Large Timber (MEG). This research checks the new visual grading and consists of 116 structural size specimens of sawn coniferous timber of Scotch pine (Pinus sylvestris L.) from Segovia, Spain. The pieces had a cross section of 150 by 200 mm. They were visually graded according to UNE 56544:2007. Also, mechanical properties have been obtained according to standard EN 408. The results show very low output with an excessive percentage of rejected pieces (33%). The main reasons for the rejection of pieces are fissures and twist
Resumo:
El proyecto tiene por objeto establecer, en el marco de la Ley 31/1995, de 8 de noviembre, sobre prevención de riesgos laborales, y en su norma reglamentaria, el Real Decreto 1627/1997 de 24 de octubre, sobre disposiciones mínimas de seguridad y salud en las obras de construcción, la identificación y evaluación de riesgos de una planta industrial de molienda de clinker para fabricación de cemento, con objeto de determinar las medidas preventivas necesarias para garantizar las adecuadas condiciones de seguridad y salud de los trabajadores que intervengan en la construcción de la obra civil, y en los montajes eléctrico y mecánico. La metodología que se empleó para estimar los niveles de riesgo se basa en la conjunción de la probabilidad estimada y las consecuencias esperadas. Los resultados obtenidos a partir de los niveles de riesgo identificados demostraron que mediante la mejora de los controles existentes y la implantación de nuevas medidas de control, priorizando de forma que éstas siempre sean proporcionales al riesgo identificado y valorado, es posible garantizar los adecuados niveles de seguridad y salud durante la ejecución de la obra. ABSTRACT The main objective of this project is, in the frame of the Law 31/1995 of November 8th about prevention of labor risks and in its regulation norm, Royal Decree 1627/1997 of October 24th, about minimum dispositions of safety and health in the works of construction, the identification and evaluation of the risks involved in an industrial plant of grinding of clinker for cement manufacture in order to determine the preventive necessary measures to ensure the suitable conditions of safety and health of the workers who take part of civil works, and of electrical and mechanical erections. The methodology chosen to estimate the risk levels is based on the probability of happening together with the awaited consequences. The results obtained from the levels of risk identified demonstrated that by means of the improvement of the existing controls and the implementation of new control measures, determining priorities always proportionally to the identified and valued risk, it is possible to guarantee the suitable levels of safety and health during the execution of the works.
Resumo:
Una de las principales causas de la actual crisis de biodiversidad es la pérdida y fragmentación del hábitat. En muchos casos, esta fragmentación es consecuencia de la construcción de infraestructuras lineales. El tramo de la carretera M-301 de Madrid estudiado es el que concentra mayor número de atropellos de anfibios en la Comunidad. Los atropellos son especialmente numerosos durante las migraciones reproductoras de los individuos (Se han registrado hasta 400 atropellos/noche). En el estudio se analiza la conectividad de la zona para el sapo común (Bufo bufo) y el sapo corredor (Bufo calamita) mediante los programas UNICOR y Circuitscape. Los resultados, como queda demostrado, presentan modelos de rutas muy próximos a la realidad. Finalmente se presentan posibles medidas correctoras útiles para anfibios y otros grupos faunísticos. El estudio proporciona herramientas para solucionar posibles problemas de conectividad del territorio que se presenten en futuros levantamientos de infraestructuras.
Resumo:
Information reconciliation is a crucial procedure in the classical post-processing of quantum key distribution (QKD). Poor reconciliation e?ciency, revealing more information than strictly needed, may compromise the maximum attainable distance, while poor performance of the algorithm limits the practical throughput in a QKD device. Historically, reconciliation has been mainly done using close to minimal information disclosure but heavily interactive procedures, like Cascade, or using less e?cient but also less interactive ?just one message is exchanged? procedures, like the ones based in low-density parity-check (LDPC) codes. The price to pay in the LDPC case is that good e?ciency is only attained for very long codes and in a very narrow range centered around the quantum bit error rate (QBER) that the code was designed to reconcile, thus forcing to have several codes if a broad range of QBER needs to be catered for. Real world implementations of these methods are thus very demanding, either on computational or communication resources or both, to the extent that the last generation of GHz clocked QKD systems are ?nding a bottleneck in the classical part. In order to produce compact, high performance and reliable QKD systems it would be highly desirable to remove these problems. Here we analyse the use of short-length LDPC codes in the information reconciliation context using a low interactivity, blind, protocol that avoids an a priori error rate estimation. We demonstrate that 2×103 bits length LDPC codes are suitable for blind reconciliation. Such codes are of high interest in practice, since they can be used for hardware implementations with very high throughput.
Resumo:
Puncturing is a well-known coding technique widely used for constructing rate-compatible codes. In this paper, we consider the problem of puncturing low-density parity-check codes and propose a new algorithm for intentional puncturing. The algorithm is based on the puncturing of untainted symbols, i.e. nodes with no punctured symbols within their neighboring set. It is shown that the algorithm proposed here performs better than previous proposals for a range of coding rates and short proportions of punctured symbols.
Resumo:
To perform Quantum Key Distribution, the mastering of the extremely weak signals carried by the quantum channel is required. Transporting these signals without disturbance is customarily done by isolating the quantum channel from any noise sources using a dedicated physical channel. However, to really profit from this technology, a full integration with conventional network technologies would be highly desirable. Trying to use single photon signals with others that carry an average power many orders of magnitude bigger while sharing as much infrastructure with a conventional network as possible brings obvious problems. The purpose of the present paper is to report our efforts in researching the limits of the integration of QKD in modern optical networks scenarios. We have built a full metropolitan area network testbed comprising a backbone and an access network. The emphasis is put in using as much as possible the same industrial grade technology that is actually used in already installed networks, in order to understand the throughput, limits and cost of deploying QKD in a real network.
Resumo:
During the 25 years of existence of the first protocol for Quantum Key Distribution, much has been said and expected of what came to be termed as Quantum Cryptography. After all this time, much progress has been done but also the reality check and analysis that naturally comes with maturity is underway. A new panorama is emerging, and the way in which the challenges imposed by market requirements are tackled will determine the fate of Quantum Cryptography. The present paper attempts to frame a reasonable view on the issues of the security and market requirements that QKD should achieve to become a marketable technology.