Los últimos poetas hebreos de Sefarad: poesía hebrea en el mundo románico

During the two decades of renaissance elapsed between the bloody events of 1391 and the year 1414, in which the Dispute of Tortosa concluded, a completely new phenomenon took place in the history of the Hebrew poetry in the Hispanic Kingdoms: A group of poets congregated in the Crown of Aragon that, in words of E. Fleischer, felt «linked by a kind of a friends' pact... and considered themselves as representatives of Hebrew poetry in Spain at the moment». They are the poets of the Circle of Zaragoza, and the same as the poets of their milieu who wrote in Romance languages, they interchanged letters in form of poems and participated in contests and disputes. The master and unquestionable leader of this group was Solomon de Piera. The study of some aspects of the work of these poets, sometimes still unpublished, allows us to conclude that they were probably influenced by the surrounding atmosphere. Romance languages were their languages; they knew the poetry of their contemporaries; they used images that could have originated in the poetic competitions of the time... There is still a lot of work to do, and it is an arduous task to determine the Romance influence in their poetry. They preferred to adhere to their past more than to be influenced by the environment. Why should they innovate? They wrote their poems in the language in which God created the world; their inspiration came from the Bible; their legacy was that of the authors of Al-Andalus... It is time of giving them back their voice and to study their work in the frame of the Romance and non Romance literatures of the Hispanic Kingdoms.During the two decades of renaissance elapsed between the bloody events of 1391 and the year 1414, in which the Dispute of Tortosa concluded, a completely new phenomenon took place in the history of the Hebrew poetry in the Hispanic Kingdoms: A group of poets congregated in the Crown of Aragon that, in words of E. Fleischer, felt «linked by a kind of a friends’ pact... and considered themselves as representatives of Hebrew poetry in Spain at the moment». They are the poets of the Circle of Zaragoza, and the same as the poets of their milieu who wrote in Romance languages, they interchanged letters in form of poems and participated in contests and disputes. The master and unquestionable leader of this group was Solomon de Piera. The study of some aspects of the work of these poets, sometimes still unpublished, allows us to conclude that they were probably influenced by the surrounding atmosphere. Romance languages were their languages; they knew the poetry of their contemporaries; they used images that could have originated in the poetic competitions of the time... There is still a lot of work to do, and it is an arduous task to determine the Romance influence in their poetry. They preferred to adhere to their past more than to be influenced by the environment. Why should they innovate? They wrote their poems in the language in which God created the world; their inspiration came from the Bible; their legacy was that of the authors of Al-Andalus... It is time of giving them back their voice and to study their work in the frame of the Romance and non Romance literatures of the Hispanic Kingdoms

Historia del texto griego del Libro de los Jueces

Tesis Univ. Complutense. Madrid.Depto. de Filología ClásicaFac. de FilologíaTRUEProQuestpu

Sparse channel estimation based on compressed sensing theory for UWB systems

Català: L'estimació de canal en receptors wireless esdevé un factor determinant a l'hora de incrementar les prestacions dels sistemes sense fils per tal de satisfer les exigències cada vegades més elevades dels consumidors en quant a velocitats de transmissió i qualitat. En aquesta tesi es proposa explotar la "sparsity" que mostren els canals wireless per tal de millorar els clàssics sistemes d'estimació de canal mitjançant les noves teòries de Compressed Sensing. Així doncs, es proposa un nou model freqüencial de senyal on el canal i un nou algoritme de reconstrucció de senyals sparse que redueix la probabilitat de detecció de falsos camins de propagació millorant d'aquesta manera l'estimació de temps d'arribada.Castellano: En los últimos años, la revolución inalámbrica se ha convertido en una realidad. Wi-fi está en todas partes, impactando significativamente en nuestro estilo de vida. Sin embargo, las comunicaciones inalámbricas nunca tendrán las condiciones de propagación igual que los cables debido a las duras condiciones de la propagación inalámbricas. El canal de radio móvil se caracteriza por la recepción múltiple, eso es que la señal recibida no sólo contiene una camino de propagación, sino también un gran número de ondas reflejadas. Estas ondas reflejadas interfieren con la onda directa, lo que provoca una degradación significativa del rendimiento del enlace. Un sistema inalámbrico debe estar diseñado de tal manera que el efecto adverso del desvanecimiento multicamino sea reducido al mínimo. Afortunadamente, el multipath puede ser visto como diversidad de información dependiendo de la cantidad de Channel State Information (CSI) disponible para el sistema. Sin embargo, en la práctica CSI rara vez se dispone a priori y debe ser estimado. Por otro lado, un canal inalámbrico a menudo puede ser modelado como un canal sparse, en la que el retraso de propagación puede ser muy grande, pero el número de caminos de propagación es normalmente muy pequeño. El conocimiento previo de la sparsity del canal se puede utilizar eficazmente para mejorar la estimación de canal utilizando la nueva teoría de Compressed Sensing (CS). CS se origina en la idea de que no es necesario invertir una gran cantidad de energía en la observación de las entradas de una señal sparse porque la mayoría de ellas será cero. Por lo tanto, CS proporciona un marco sólido para la reducción del número de medidas necesarias para resumir señales sparse. La estimación de canal sparse se centra en este trabajo en Ultra-Wideband (UWB) porque la gran resolución temporal que proporcionan las señales UWB se traduce en un número muy grande de componentes multipath que se pueden resolver. Por lo tanto, UWB mitiga significativamente la distorsión de trayectoria múltiple y proporciona la diversidad multicamino. Esta diversidad junto con la resolución temporal de las señales UWB crear un problema de estimación de canal muy interesante. En esta tesis se estudia el uso de CS en la estimación de canal altamente sparse por medio de un nuevo enfoque de estimación basado en el modelo de frecuencial de la señal UWB. También se propone un nuevo algoritmo llamado extended Orthogonal Matching Pursuit (eOMP) basado en los mismos principios que el clásico OMP, con el fin de mejorar algunas de sus característica.English: In recent years, the wireless revolution has become a reality. Wireless is everywhere having significant impact on our lifestyle. However, wireless will never have the same propagation conditions as wires due to the harsh conditions of the wireless propagation. The mobile radio channel is characterized by multipath reception, that is the signal offered to the receiver contains not only a direct line-of-sight radio wave, but also a large number of reflected radio waves. These reflected waves interfere with the direct wave, which causes significant degradation of the performance of the link. A wireless system has to be designed in such way that the adverse effect of multipath fading is minimized. Fortunately, multipath can be seen as a blessing depending on the amount of Channel State Information (CSI) available to the system. However, in practise CSI is seldom available a priori and needs to be estimated. On the other hand, a wireless channel can often be modeled as a sparse channel in which the delay spread could be very large, but the number of significant paths is normally very small. The prior knowledge of the channel sparseness can be effectively use to improve the channel estimation using the novel Compressed Sensing (CS) theory. CS originates from the idea that is not necessary to invest a lot of power into observing the entries of a sparse signal because most of them will be zero. Therefore, CS provides a robust framework for reducing the number of measurement required to summarize sparse signals. The sparse channel estimation here is focused on Ultra-WideBand (UWB) systems because the very fine time resolution of the UWB signal results in a very large number of resolvable multipath components. Consequently, UWB significantly mitigates multipath distortion and provides path diversity. The rich multipath coupled with the fine time resolution of the UWB signals create a challenging sparse channel estimation problem. This Master Thesis examines the use of CS in the estimation of highly sparse channel by means of a new sparse channel estimation approach based on the frequency domain model of the UWB signal. It is also proposed a new greedy algorithm named extended Orthogonal Matching Pursuit (eOMP) based on the same principles than classical Orthogonal Matching Pursuit (OMP) in order to improve some OMP characteristics. Simulation results show that the new eOMP provides lower false path detection probability compared with classical OMP, which also leads to a better TOA estimation without significant degradation of the channel estimation. Simulation results will also show that the new frequency domain sparse channel model outperforms other models presented in the literature

Estimación conjunta de TOA y DOA en sistemas UWB para localización

El objetivo de este proyecto es el diseño de un algoritmo de localización para sistemas con tecnología Ultra-Wideband (UWB)