43,724 research outputs found
Recommended from our members
The David W. Fentress Family Letters, 1856-1969
No full textTranscript of a letter by an unidentified author to David Fentress regarding sharing federal newspapers and the banning of federal newspapers in some areas. The author passes on the news of the war including the destruction of the Federal merchantmen by the Confederate fleet. He passes along world news: Russia preparing to go to War with Europe and how that could negatively affect the Confederacy. There is also speculation on the future of the war
The David W. Fentress Family Letters, 1856-1969
No full textTranscript of a letter by an unidentified author to David Fentress regarding sharing federal newspapers and the banning of federal newspapers in some areas. The author passes on the news of the war including the destruction of the Federal merchantmen by the Confederate fleet. He passes along world news: Russia preparing to go to War with Europe and how that could negatively affect the Confederacy. There is also speculation on the future of the war
Control de la dispersión en antenas de onda de fuga planas para su uso en diferentes aplicaciones
No full text[SPA] Esta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones. Las antenas de onda de fuga (leaky-wave antennas o LWA) son un tipo de antenas muy conocido que consiste en una estructura de guía de onda con un mecanismo que permite la fuga de parte de la potencia que viaja por su interior. Por este motivo, también se conocen como "travelling-wave antennas". La fuga de potencia es la responsable de la radiación y, si se controla la propagación de la onda a lo largo de la estructura de guía de onda, el diagrama de radiación de la antena puede ser modelado de diferentes maneras. Hasta la fecha, a pesar de las buenas características de las LWAs como el escaneo de haz en frecuencia, la alta directividad o su sencillo mecanismo de alimentación, su uso en aplicaciones reales no está muy extendido, siendo los radares de onda continúa modulada en frecuencia o los sistemas de enfoque de campo cercano controlado en frecuencia algunos de ellos. Los primeros diseños de LWAs se basaban en la tecnología de guías de onda de gran tamaño, pero recientemente, la posibilidad de fabricar LWAs en tecnología plana, como la guía de onda integrada en el sustrato (substrate-integrated waveguide o SIW), abre una nueva variedad de aplicaciones, ya que combina sus buenas características con el bajo perfil, la integrabilidad y el bajo coste. En este contexto, el control de la dispersión de las LWAs planas (PLWA), que es su comportamiento al variar la frecuencia de la señal de alimentación, puede extender su uso a aplicaciones en las que, a priori, no son la solución más óptima, como las comunicaciones punto a punto, ya que el ancho de banda se reduce debido al escaneo de haz en frecuencia. De este modo, se pueden aprovechar las ventajas de las LWA, reduciendo los inconvenientes que las hacían útiles sólo para algunas aplicaciones. Además, se pueden diseñar nuevas aplicaciones teniendo en cuenta los principios de funcionamiento de las LWAs en el proceso de diseño, como la localización de dispositivos móviles en escenarios de Internet de las Cosas (Internet of Things o IoT) o los sistemas de Transmisión Inalámbrica de Energía (wireless power transfer o WPT) para Redes de Sensores Inalámbricos (wireless sensor networks o WSN). Esto cambia el paradigma del diseño de antenas, en el que ahora la antena no es una parte modular del sistema, sino que el sistema global se desarrolla teniendo en cuenta las características de las antenas. La principal aportación de esta Tesis es el estudio, análisis y diseño de PLWAs con el fin de aumentar su aplicabilidad donde sus características puedan ser de interés. Se han elegido tres aplicaciones principales, que definen los tres bloques principales de la tesis: - Reducción del escaneo de haz para las comunicaciones Punto a Punto: El objetivo aquí es reducir el escaneo de haz en frecuencia, inherente a la naturaleza de las PLWAs, para hacerlas adecuadas para las comunicaciones Punto a Punto. - Sistema basado en PLWAs para la localización de dispositivos en escenarios IoT: Aquí, el comportamiento de escaneo en frecuencia de las PLWAs se utiliza como base para diseñar un sistema de estimación de dirección que sea compatible con los actuales dispositivos móviles comerciales en el marco del IoT. Se ha desarrollado y probado un prototipo que muestra una mejora de las prestaciones respecto a trabajos anteriores con el mismo objetivo. - Sistema de transferencia de energía inalámbrica para redes de sensores inalámbricos con PLWAs: El último objetivo era diseñar una PLWA que fuera útil en un sistema de transferencia inalámbrica de energía electromagnética para alimentar Redes de Sensores Inalámbricos. Este documento se presenta como una Tesis por compendio, por lo que se presentarán y explicarán brevemente los 5 artículos de revista que se han publicado durante el programa de doctorado. Además, también se presentarán algunos artículos de conferencias y otro trabajo en revisión para exponer algunas de las investigaciones que no han sido publicadas en revistas. El documento está organizado de la siguiente manera: En la Introducción se da una mejor contextualización sobre las LWAs y las tres aplicaciones mencionadas anteriormente junto con los principales objetivos de la Tesis. Las tres siguientes partes están dedicadas a presentar y comentar los trabajos publicados en cada una de las principales aplicaciones, esto es, la reducción del escaneo de haz en frecuencia en la Parte I, la localización de dispositivos en escenarios IoT en la Parte II y WPT en la Parte III. Finalmente, en la Parte IV, se discuten las conclusiones generales y las futuras líneas de investigación.[ENG] This doctoral dissertation has been presented in the form of thesis by publication. Leaky-Wave Antennas (LWA) are a well known type of antennas that consist on a waveguiding structure with a mechanism that allows the leakage of some of the power that is travelling inside it. For this reason, they are also known as “Travelling-Wave Antennas”. The leakage of power is the responsible for the radiation and, if the propagation of the wave along the waveguiding structure is controlled, the radiation pattern of the antenna can be shaped in different ways. To date, despite the good characteristics of LWAs like the frequency scanning, high directivity or their simple feeding mechanism, their use in real applications is not very extended, being frequency modulated continuous wave radars or near-field frequency controlled focusing systems some of them. The first LWA designs were based on bulky waveguide technology, but recently, the possibility to design and manufacture LWAs in planar technology, such as the Substrate-Integrated Waveguide (SIW), opens a new variety of applications, since it combines their good characteristics with low profile, integrability and low cost. In this context, the control of the dispersion of planar LWAs (PLWA), which is their behaviour as the frequency of the feeding signal is varied, can extend their use to applications in which, a priori, they are not the most optimal solution, such as point-to-point communications, since the bandwidth is reduced due to the frequency scanning. Thus, the benefits of LWAs can be exploited, reducing the drawbacks that kept them useful for just a few applications. Moreover, new applications can be designed, taking into account the working principles of LWAs in the design process, such as localization of mobile devices in Internet of Things (IoT) scenarios or Wireless Power Transfer (WPT) systems for Wireless Sensor Networks (WSN). This changes the paradigm of antenna design, in which now the antenna is not a modular part of the system, but instead the overall system is developed taking into account the antennas’ characteristics. The main contribution of this Thesis is the study, analysis and design of PLWAs in order to increase their applicability where their benefits can be of interest. Three main applications have been chosen, defining the three main blocks of this document: • Reduction of beam scanning for Point to Point communications: The objective here is to reduce the frequency scanning, inherent to the nature of PLWAs, in order to make them suitable for Point to Point communications. • PLWA-based system for localization in IoT scenarios: Here, the frequency scanning performance of LWAs is used as the base for designing a direction finding system which is compatible with current commercial IoT mobile devices. A prototype was developed and tested, showing an improvement of performance with respect to previous works with the same objective. • Wireless Power Transfer system for Wireless Sensor Networks with PLWA: The last objective was to design a PLWA that was useful in a system for wireless transfer of electromagnetic energy to power Wireless Sensor Networks. This document is presented as a Thesis by compilation, so the 5 journal articles that have been published during the Ph.D program will be presented and briefly explained. Besides, some conference articles and other work under review will be also presented to expose some of the research that has not been published in journals. The document is organized as follows: In chapter 1, a better contextualization about LWAs and the three applications mentioned above is given along with the main objectives of the Thesis. The next three parts are dedicated to present and comment the published works in each of the main applications, this is, reduction of beam scanning in Part I, IoT localization in Part II and WPT in Part III. Finally, in Part IV, the overall conclusions and the future research lines are discussed.Escuela Internacional de Doctorado de la Universidad Politécnica de CartagenaPrograma de Doctorado en Tecnologías de la Información y las ComunicacionesEsta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones. Está formada por un total de 12 artículos: 1. M. Poveda-Garcia, D. Cañete-Rebenaque, G. Goussetis, and J. L. Gomez-Tornero, “Coupling Substrate-Integrated Waveguides to Increase the Gain Bandwidth of Leaky-Wave Antennas” IEEE Transactions on Microwave Theory and Techniques, vol. 66, no. 6, pp. 3099-3109, 2018. 2. M. Poveda-Garcia, D. Cañete-Rebenaque, and J. L. Gomez-Tornero, “Frequency-Scanned Monopulse Pattern Synthesis Using Leaky-Wave Antennas for Enhanced Power-Based Direction-of-Arrival Estimation” IEEE Transactions on Antennas and Propagation, vol. 67, no. 11, pp. 7071-7086, 2019. 3. M. Poveda-Garcia, A. Gomez-Alcaraz, D. Cañete-Rebenaque, A. S. Martinez-Sala, and J. L. Gomez-Tornero, “RSSI-Based direction-of-departure estimation in bluetooth low energy using an array of frequency-steered leaky-wave antennas” IEEE Access, vol. 8, pp. 9380-9394, 2020. 4. M. Poveda-Garcia and J. L. Gomez-Tornero, “Ambiguity Resolution in Amplitude-Monopulse Systems using Broad-Beam Patterns” in IEEE Antennas and Wireless Propagation Letters, vol. 40, no. 4, pp. 503-507, 2021. 5. M. Poveda-Garcia, J. Oliva-Sanchez, R. Sanchez-Iborra, D. Cañete-Rebenaque and J. L. Gomez-Tornero, “Dynamic Wireless Power Transfer for Cost-Effective Wireless Sensor Networks Using Frequency-Scanned Beaming” in IEEE Access, vol. 7, pp. 8081-8094, 2019. 6. M. Poveda-Garcia, S. K. Podilchak, G. Goussetis, and J. L. Gomez-Tornero, “Millimeter-Wave Substrate-Integrated Waveguide Based Leaky-Wave Antenna With Broadbeam Radiation at Broadside” 12th European Conference on Antennas and Propagation (EuCAP), London, pp. 1-5, 2018. 6. M. Poveda-Garcia, S. K. Podilchak, G. Goussetis, and J. L. Gomez-Tornero, “Millimeter-Wave Substrate-Integrated Waveguide Based Leaky-Wave Antenna With Broadbeam Radiation at Broadside” 12th European Conference on Antennas and Propagation (EuCAP), London, pp. 1-5, 2018. 7. M. Poveda-Garcia, J. L. Gomez-Tornero, and D. Cañete-Rebenaque,“Study of the Efficiency of Half-Width Substrate Integrated Waveguide Leaky-Wave Antennas in FR4” in 2nd URSI AT-RASC, 2018, pp. 1-4. 8. M. Poveda-Garcia, A. Gil-Martinez and J. L. Gomez-Tornero, “Frequency-Scanned Focused Leaky-Wave Antennas for Direction-of-Arrival Detection in Proximity BLE Sensing Applications” 14th European Conference on Antennas and Propagation (EuCAP), Copenhagen, pp. 1-4, 2020. 9. M. Poveda-Garcia, E. Andreu-Garcia, J. Garcia-Fernandez, D. Cañete-Rebenaque and J. L. Gomez-Tornero “Frequency-Scanned Leaky-Wave Antenna Topologies for Two-dimensional Direction of Arrival Estimation in IoT Wireless Networks” 2021 15th European Conference on Antennas and Propagation (EuCAP), Online, 2021. 10. M. Poveda-Garcia and J. L. Gomez-Tornero, “Beaming Efficiency of 1-D Frequency-Scanned Based Radiative WPT System for Wireless Sensor Networks” 2019 IEEE Wireless Power Transfer Conference (WPTC), London, 2019, pp. 338-342. 11. M. Poveda-Garcia and J. L. Gomez-Tornero, “Two-Dimensional Quasi-Bessel Beam Synthesis and Frequency-Scanning Leaky-Wave Launchers” 2019 PhotonIcs and Electromagnetics Research Symposium - Spring (PIERS-Spring), Rome, 2019, pp. 295-302. 12. M. Poveda-Garcia, R. Guzman-Quiros, D. Cañete-Rebenaque, and J. L. Gomez-Tornero, “Defocusing Leaky-Wave Antennas to Overcome the Directivity-Bandwidth Product” XXXII Simposium Nacional de la Union Cientifica Internacional de Radio (URSI 2009), Cartagena, Spain, Sep. 2017.Universidad Politécnica de Cartagen
Portrait of author David Foster at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Author David Foster with academic Jeff Doyle at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Author David Foster and academic Jeff Doyle at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
David Braithwaite at White Waltham Steam Fair
No full textDavid Braithwaite, fairground enthusiast and author photographed at White Waltham Steam Fair, August 1964
David Zimmer Christmas letter
No full textThis Christmas letter written November 30, 1999, by David Zimmer is titled "Season's Greetings from the last of the Red-Hot-Santas!" It features an illustration of Santa Claus with a guitar, and a summary of Zimmer's year.
David Zimmer (1929-2005) was born in Harrisburg, Ohio. He enlisted in the U.S. Army and served for two years during the Korean War at the Brooke Army Medical Center in San Antonio, where he performed in drag for wounded soldiers. After the war, he returned to Ohio. Zimmer performed as Dolly Divine, a name inspired by the song "Hello Dolly." In 1964, he established the Berwick Ball with Orn Huntington, another important early gay activist in Central Ohio. The Ball began as a formal Halloween costume ball that provided a safe space to gather and enjoy drag shows for the gay community each year; over the years, it grew into an annual Halloween tradition and an important fundraiser for the AIDS movement and other charities. During the 1970s, Zimmer was also known for hosting lavish parties at his Harrisburg home. In 1989, he moved to the German Village area of Columbus where he remained active in the community. During the 1990s, Zimmer continued to perform in and out of drag and commissioned costume designer Dick Frank to make elaborate outfits. Zimmer worked for Huntington National Bank for 39 years and was a member of the Harrisburg United Methodist Church, Veterans of Foreign Wars and the German Village Society
David Zimmer Christmas letter
No full textThis Christmas letter was written December 7, 2004, by David Zimmer. It features a small illustration of Santa Claus, a summary of Zimmer's year, and a clipping from the Village Crier recognizing his 75th birthday celebration.
David Zimmer (1929-2005) was born in Harrisburg, Ohio. He enlisted in the U.S. Army and served for two years during the Korean War at the Brooke Army Medical Center in San Antonio, where he performed in drag for wounded soldiers. After the war, he returned to Ohio. Zimmer performed as Dolly Divine, a name inspired by the song "Hello Dolly." In 1964, he established the Berwick Ball with Orn Huntington, another important early gay activist in Central Ohio. The Ball began as a formal Halloween costume ball that provided a safe space to gather and enjoy drag shows for the gay community each year; over the years, it grew into an annual Halloween tradition and an important fundraiser for the AIDS movement and other charities. During the 1970s, Zimmer was also known for hosting lavish parties at his Harrisburg home. In 1989, he moved to the German Village area of Columbus where he remained active in the community. During the 1990s, Zimmer continued to perform in and out of drag and commissioned costume designer Dick Frank to make elaborate outfits. Zimmer worked for Huntington National Bank for 39 years and was a member of the Harrisburg United Methodist Church, Veterans of Foreign Wars and the German Village Society
Juana María Poveda, violonchelo (Colombia)
No full textConcierto interpretado por la violonchelista Juana María Póveda, en compañía del violonchelista José David Acosta. Póveda nació en 1989. Inició sus estudios musicales en la Fundación Batuta con Gabriel Guzmán y en 2006 ingresó a la Escuela de Música de Cámara de Bogotá, siempre bajo la guía de Gabriel Guzmán y de Adriana Marín.
En 2005 obtuvo la beca Ruta Quetzal BBVA 2005, por una composición de su autoría para violonchelo solo, y en 2009 obtuvo el Diploma ATCL Recital de la Trinity College of London, como una distinción por su desempeño como intérprete. En 2010 hizo parte de la Orquesta Filarmónica Joven de Colombia, participó en la temporada de conciertos del Auditorio Fabio Lozano y fue seleccionada para la temporada 2011 en la Serie de los jóvenes intérpretes del Banco de la República. Ha recibido clases magistrales con Aldo Mata, Suren Bagratuni, Kristina Reiko Cooper, Alisa Weilerstein y Nicholas Tzavaras. Y estudió en la Scuola di Música di Fiesole en Florencia (Italia) con la maestra Marianne Che
- …
