Dissertations / Theses on the topic 'Array theory'

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1

Huang, J. "Frequency diversity array : theory and design." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/624503/.

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This thesis presents a novel concept of beam scanning and forming by employing frequency diversity in an array antenna. It is shown that by applying a linear frequency shift to the CW signals across the elements, a periodically scanning beam pattern is generated and the main beam direction is a function of time and range. Moreover, when transmitting a pulse signal, the frequency diversity array (FDA) can be used for beam forming in radar applications. These properties offer a more flexible beam scanning and forming option over traditional phase shifter implementations. The thesis begins with the discussion on FDA’s array factor. It is mathematically proven that the array factor is a periodic function of time and range and the scanning period itself is a function of the linear frequency shift. Then further discussion is made when a pulsed signal is transmitted by an FDA. The requirement on the pulse width for a certain linear frequency shift is specified and corresponding signal processing technique is provided for the frequency diverse signal receiver. The thesis subsequently goes on to an electromagnetic simulation of FDA. The CST Microwave Studio is utilized to model the FDA and simulate its transient field, which allows one to verify the relationship between the scanning period and the linear frequency shift. Finally, the implementation of FDA is considered with the focus laid on the generation of the required frequency diverse signals complying with the two basic assumptions. The PLL frequency synthesis technique is introduced as an effective approach of generating the frequency diverse signals. One low cost and profile design of integer-N frequency synthesizer is presented to illustrate the basic design considerations and guidelines. For comparison, a Σ − Δ fractional-N frequency synthesizer produced by Analog Device is introduced for designs where more budget is available.
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2

Arribas, Lázaro Javier. "GNSS array-based acquisition: theory and implementation." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/125031.

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This Dissertation addresses the signal acquisition problem using antenna arrays in the general framework of Global Navigation Satellite Systems (GNSS) receivers. The term GNSS classi es those navigation systems based on a constellation of satellites, which emit ranging signals useful for positioning. Although the American GPS is already available, which coexists with the renewed Russian Glonass, the forthcoming European contribution (Galileo) along with the Chinese Compass will be operative soon. Therefore, a variety of satellite constellations and signals will be available in the next years. GNSSs provide the necessary infrastructures for a myriad of applications and services that demand a robust and accurate positioning service. The positioning availability must be guaranteed all the time, specially in safety-critical and mission-critical services. Examining the threats against the service availability, it is important to take into account that all the present and the forthcoming GNSSs make use of Code Division Multiple Access (CDMA) techniques. The ranging signals are received with very low precorrelation signal-to-noise ratio (in the order of 􀀀���22 dB for a receiver operating at the Earth surface). Despite that the GNSS CDMA processing gain o ers limited protection against Radio Frequency interferences (RFI), an interference with a interference-to-signal power ratio that exceeds the processing gain can easily degrade receivers' performance or even deny completely the GNSS service, specially conventional receivers equipped with minimal or basic level of protection towards RFIs. As a consequence, RFIs (either intentional or unintentional) remain as the most important cause of performance degradation. A growing concern of this problem has appeared in recent times. Focusing our attention on the GNSS receiver, it is known that signal acquisition has the lowest sensitivity of the whole receiver operation, and, consequently, it becomes the performance bottleneck in the presence of interfering signals. A single-antenna receiver can make use of time and frequency diversity to mitigate interferences, even though the performance of these techniques is compromised in low SNR scenarios or in the presence of wideband interferences. On the other hand, antenna arrays receivers can bene t from spatial-domain processing, and thus mitigate the e ects of interfering signals. Spatial diversity has been traditionally applied to the signal tracking operation of GNSS receivers. However, initial tracking conditions depend on signal acquisition, and there are a number of scenarios in which the acquisition process can fail as stated before. Surprisingly, to the best of our knowledge, the application of antenna arrays to GNSS signal acquisition has not received much attention. This Thesis pursues a twofold objective: on the one hand, it proposes novel arraybased acquisition algorithms using a well-established statistical detection theory framework, and on the other hand demonstrates both their real-time implementation feasibility and their performance in realistic scenarios. The Dissertation starts with a brief introduction to GNSS receivers fundamentals, providing some details about the navigation signals structure and the receiver's architecture of both GPS and Galileo systems. It follows with an analysis of GNSS signal acquisition as a detection problem, using the Neyman-Pearson (NP) detection theory framework and the single-antenna acquisition signal model. The NP approach is used here to derive both the optimum detector (known as clairvoyant detector ) and the sov called Generalized Likelihood Ratio Test (GLRT) detector, which is the basis of almost all of the current state-of-the-art acquisition algorithms. Going further, a novel detector test statistic intended to jointly acquire a set of GNSS satellites is obtained, thus reducing both the acquisition time and the required computational resources. The eff ects of the front-end bandwidth in the acquisition are also taken into account. Then, the GLRT is extended to the array signal model to obtain an original detector which is able to mitigate temporally uncorrelated interferences even if the array is unstructured and moderately uncalibrated, thus becoming one of the main contributions of this Dissertation. The key statistical feature is the assumption of an arbitrary and unknown covariance noise matrix, which attempts to capture the statistical behavior of the interferences and other non-desirable signals, while exploiting the spatial dimension provided by antenna arrays. Closed form expressions for the detection and false alarm probabilities are provided. Performance and interference rejection capability are modeled and compared both to their theoretical bound. The proposed array-based acquisition algorithm is also compared to conventional acquisition techniques performed after blind null-steering beamformer approaches, such as the power minimization algorithm. Furthermore, the detector is analyzed under realistic conditions, accounting for the presence of errors in the covariance matrix estimation, residual Doppler and delay errors, and signal quantization e ects. Theoretical results are supported by Monte Carlo simulations. As another main contribution of this Dissertation, the second part of the work deals with the design and the implementation of a novel Field Programmable Gate Array (FPGA)-based GNSS real-time antenna-array receiver platform. The platform is intended to be used as a research tool tightly coupled with software de ned GNSS receivers. A complete signal reception chain including the antenna array and the multichannel phase-coherent RF front-end for the GPS L1/ Galileo E1 was designed, implemented and tested. The details of the digital processing section of the platform, such as the array signal statistics extraction modules, are also provided. The design trade-o s and the implementation complexities were carefully analyzed and taken into account. As a proof-of-concept, the problem of GNSS vulnerability to interferences was addressed using the presented platform. The array-based acquisition algorithms introduced in this Dissertation were implemented and tested under realistic conditions. The performance of the algorithms were compared to single antenna acquisition techniques, measured under strong in-band interference scenarios, including narrow/wide band interferers and communication signals. The platform was designed to demonstrate the implementation feasibility of novel array-based acquisition algorithms, leaving the rest of the receiver operations (mainly, tracking, navigation message decoding, code and phase observables, and basic Position, Velocity and Time (PVT) solution) to a Software De ned Radio (SDR) receiver running in a personal computer, processing in real-time the spatially- ltered signal sample stream coming from the platform using a Gigabit Ethernet bus data link. In the last part of this Dissertation, we close the loop by designing and implementing such software receiver. The proposed software receiver targets multi-constellation/multi-frequency architectures, pursuing the goals of e ciency, modularity, interoperability, and exibility demanded by user domains that require non-standard features, such as intermediate signals or data extraction and algorithms interchangeability. In this context, we introduce an open-source, real-time GNSS software de ned receiver (so-named GNSS-SDR) that contributes with several novel features such as the use of software design patterns and shared memory techniques to manage e ciently the data ow between receiver blocks, the use of hardware-accelerated instructions for time-consuming vector operations like carrier wipe-o and code correlation, and the availability to compile and run on multiple software platforms and hardware architectures. At this time of writing (April 2012), the receiver enjoys of a 2-dimensional Distance Root Mean Square (DRMS) error lower than 2 meters for a GPS L1 C/A scenario with 8 satellites in lock and a Horizontal Dilution Of Precision (HDOP) of 1.2.
Esta tesis aborda el problema de la adquisición de la señal usando arrays de antenas en el marco general de los receptores de Sistemas Globales de Navegación por Satélite (GNSS). El término GNSS engloba aquellos sistemas de navegación basados en una constelación de satélites que emiten señales útiles para el posicionamiento. Aunque el GPS americano ya está disponible, coexistiendo con el renovado sistema ruso GLONASS, actualmente se está realizando un gran esfuerzo para que la contribución europea (Galileo), junto con el nuevo sistema chino Compass, estén operativos en breve. Por lo tanto, una gran variedad de constelaciones de satélites y señales estarán disponibles en los próximos años. Estos sistemas proporcionan las infraestructuras necesarias para una multitud de aplicaciones y servicios que demandan un servicio de posicionamiento confiable y preciso. La disponibilidad de posicionamiento se debe garantizar en todo momento, especialmente en los servicios críticos para la seguridad de las personas y los bienes. Cuando examinamos las amenazas de la disponibilidad del servicio que ofrecen los GNSSs, es importante tener en cuenta que todos los sistemas presentes y los sistemas futuros ya planificados hacen uso de técnicas de multiplexación por división de código (CDMA). Las señales transmitidas por los satélites son recibidas con una relación señal-ruido (SNR) muy baja, medida antes de la correlación (del orden de -22 dB para un receptor ubicado en la superficie de la tierra). A pesar de que la ganancia de procesado CDMA ofrece una protección inherente contra las interferencias de radiofrecuencia (RFI), esta protección es limitada. Una interferencia con una relación de potencia de interferencia a potencia de la señal que excede la ganancia de procesado puede degradar el rendimiento de los receptores o incluso negar por completo el servicio GNSS. Este riesgo es especialmente importante en receptores convencionales equipados con un nivel mínimo o básico de protección frente las RFIs. Como consecuencia, las RFIs (ya sean intencionadas o no intencionadas), se identifican como la causa más importante de la degradación del rendimiento en GNSS. El problema esta causando una preocupación creciente en los últimos tiempos, ya que cada vez hay más servicios que dependen de los GNSSs Si centramos la atención en el receptor GNSS, es conocido que la adquisición de la señal tiene la menor sensibilidad de todas las operaciones del receptor, y, en consecuencia, se convierte en el factor limitador en la presencia de señales interferentes. Un receptor de una sola antena puede hacer uso de la diversidad en tiempo y frecuencia para mitigar las interferencias, aunque el rendimiento de estas técnicas se ve comprometido en escenarios con baja SNR o en presencia de interferencias de banda ancha. Por otro lado, los receptores basados en múltiples antenas se pueden beneficiar del procesado espacial, y por lo tanto mitigar los efectos de las señales interferentes. La diversidad espacial se ha aplicado tradicionalmente a la operación de tracking de la señal en receptores GNSS. Sin embargo, las condiciones iniciales del tracking dependen del resultado de la adquisición de la señal, y como hemos visto antes, hay un número de situaciones en las que el proceso de adquisición puede fallar. En base a nuestro grado de conocimiento, la aplicación de los arrays de antenas a la adquisición de la señal GNSS no ha recibido mucha atención, sorprendentemente. El objetivo de esta tesis doctoral es doble: por un lado, proponer nuevos algoritmos para la adquisición basados en arrays de antenas, usando como marco la teoría de la detección de señal estadística, y por otro lado, demostrar la viabilidad de su implementación y ejecución en tiempo real, así como su medir su rendimiento en escenarios realistas. La tesis comienza con una breve introducción a los fundamentos de los receptores GNSS, proporcionando algunos detalles sobre la estructura de las señales de navegación y la arquitectura del receptor aplicada a los sistemas GPS y Galileo. Continua con el análisis de la adquisición GNSS como un problema de detección, aplicando la teoría del detector Neyman-Pearson (NP) y el modelo de señal de una única antena. El marco teórico del detector NP se utiliza aquí para derivar tanto el detector óptimo (conocido como detector clarividente) como la denominada Prueba Generalizada de la Razón de Verosimilitud (en inglés, Generalized Likelihood Ratio Test (GLRT)), que forma la base de prácticamente todos los algoritmos de adquisición del estado del arte actual. Yendo más lejos, proponemos un nuevo detector diseñado para adquirir simultáneamente un conjunto de satélites, por lo tanto, obtiene una reducción del tiempo de adquisición y de los recursos computacionales necesarios en el proceso, respecto a las técnicas convencionales. El efecto del ancho de banda del receptor también se ha tenido en cuenta en los análisis. A continuación, el detector GLRT se extiende al modelo de señal de array de antenas para obtener un detector nuevo que es capaz de mitigar interferencias no correladas temporalmente, incluso utilizando arrays no estructurados y moderadamente descalibrados, convirtiéndose así en una de las principales aportaciones de esta tesis. La clave del detector es asumir una matriz de covarianza de ruido arbitraria y desconocida en el modelo de señal, que trata de captar el comportamiento estadístico de las interferencias y otras señales no deseadas, mientras que utiliza la dimensión espacial proporcionada por los arrays de antenas. Se han derivado las expresiones que modelan las probabilidades teóricas de detección y falsa alarma. El rendimiento del detector y su capacidad de rechazo a interferencias se han modelado y comparado con su límite teórico. El algoritmo propuesto también ha sido comparado con técnicas de adquisición convencionales, ejecutadas utilizando la salida de conformadores de haz que utilizan algoritmos de filtrado de interferencias, como el algoritmo de minimización de la potencia. Además, el detector se ha analizado bajo condiciones realistas, representadas con la presencia de errores en la estimación de covarianzas, errores residuales en la estimación del Doppler y el retardo de señal, y los efectos de la cuantificación. Los resultados teóricos se apoyan en simulaciones de Monte Carlo. Como otra contribución principal de esta tesis, la segunda parte del trabajo trata sobre el diseño y la implementación de una nueva plataforma para receptores GNSS en tiempo real basados en array de antenas que utiliza la tecnología de matriz programable de puertas lógicas (en ingles Field Programmable Gate Array (FPGA)). La plataforma está destinada a ser utilizada como una herramienta de investigación estrechamente acoplada con receptores GNSS definidos por software. Se ha diseñado, implementado y verificado la cadena completa de recepción, incluyendo el array de antenas y el front-end multi-canal para las señales GPS L1 y Galileo E1. El documento explica en detalle el procesado de señal que se realiza, como por ejemplo, la implementación del módulo de extracción de estadísticas de la señal. Los compromisos de diseño y las complejidades derivadas han sido cuidadosamente analizadas y tenidas en cuenta. La plataforma ha sido utilizada como prueba de concepto para solucionar el problema presentado de la vulnerabilidad del GNSS a las interferencias. Los algoritmos de adquisición introducidos en esta tesis se han implementado y probado en condiciones realistas. El rendimiento de los algoritmos se comparó con las técnicas de adquisición basadas en una sola antena. Se han realizado pruebas en escenarios que contienen interferencias dentro de la banda GNSS, incluyendo interferencias de banda estrecha y banda ancha y señales de comunicación. La plataforma fue diseñada para demostrar la viabilidad de la implementación de nuevos algoritmos de adquisición basados en array de antenas, dejando el resto de las operaciones del receptor (principalmente, los módulos de tracking, decodificación del mensaje de navegación, los observables de código y fase, y la solución básica de Posición, Velocidad y Tiempo (PVT)) a un receptor basado en el concepto de Radio Definida por Software (SDR), el cual se ejecuta en un ordenador personal. El receptor procesa en tiempo real las muestras de la señal filltradas espacialmente, transmitidas usando el bus de datos Gigabit Ethernet. En la última parte de esta Tesis, cerramos ciclo diseñando e implementando completamente este receptor basado en software. El receptor propuesto está dirigido a las arquitecturas de multi-constalación GNSS y multi-frecuencia, persiguiendo los objetivos de eficiencia, modularidad, interoperabilidad y flexibilidad demandada por los usuarios que requieren características no estándar, tales como la extracción de señales intermedias o de datos y intercambio de algoritmos. En este contexto, se presenta un receptor de código abierto que puede trabajar en tiempo real, llamado GNSS-SDR, que contribuye con varias características nuevas. Entre ellas destacan el uso de patrones de diseño de software y técnicas de memoria compartida para administrar de manera eficiente el uso de datos entre los bloques del receptor, el uso de la aceleración por hardware para las operaciones vectoriales más costosas, como la eliminación de la frecuencia Doppler y la correlación de código, y la disponibilidad para compilar y ejecutar el receptor en múltiples plataformas de software y arquitecturas de hardware. A fecha de la escritura de esta Tesis (abril de 2012), el receptor obtiene un rendimiento basado en la medida de la raíz cuadrada del error cuadrático medio en la distancia bidimensional (en inglés, 2-dimensional Distance Root Mean Square (DRMS) error) menor de 2 metros para un escenario GPS L1 C/A con 8 satélites visibles y una dilución de la precisión horizontal (en inglés, Horizontal Dilution Of Precision (HDOP)) de 1.2.
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3

Dalevi, Mathias. "S-Band Antenna Array." Thesis, Uppsala University, Astronomy and Space Physics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-126302.

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This report presents concepts for a planar active electronically scanned antenna(AESA). The goal of the project was to devlop a low-weight, low profile, thin, S-band antenna with wide-scan angle capabilities. In the final concept the service aspects of the T/R-modules was also taken into acount in order to allow easy and fast replacements of these components. The antenna was designed and optimised using the commercial software Ansoft HFSS. A prototype of the antenna was constructed and later measured and verified. The final concept is a 2m×2m antenna with an estimated weight of around 320 kg, around 11 cm thick (where the thickness of the antenna element is 1.76 cm) and has a maximum scan angle range of more than 45 degrees (with <–10dB active reflection) in the frequency band 3–3.5 GHz.

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Mardani, Reza. "High resolution algorithms for array signal processing." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292417.

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Daniel, J. S. "Synthesis and decoding of array error control codes." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374587.

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Cotterell, Philip S. "On the theory of second-order soundfield microphone." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250639.

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7

Glotzbach, John William. "A Color Filter Array Interpolation Method Based on Sampling Theory." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4785.

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Digital cameras use a single image sensor array with a color filter array (CFA) to measure a color image. Instead of measuring a red, green, and blue value at every pixel, these cameras have a filter built onto each pixel so that only one portion of the visible spectrum is measured. To generate a full-color image, the camera must estimate the missing two values at every pixel. This process is known as color filter array interpolation. The Bayer CFA pattern samples the green image on half of the pixels of the imaging sensor on a quincunx grid. The other half of the pixels measure the red and blue images equally on interleaved rectangular sampling grids. This thesis analyzes this problem with sampling theory. The red and blue images are sampled at half the rate of the green image and therefore have a higher probability of aliasing in the output image. This is apparent when simple interpolation algorithms like bilinear interpolation are used for CFA interpolation. Two reference algorithms, a projections onto convex sets (POCS) algorithm and an edge-directed algorithm by Adams and Hamilton (AH), are studied. Both algorithms address aliasing in the green image. Because of the high correlation among the red, green, and blue images, information from the red and blue images can be used to better interpolate the green image. The reference algorithms are studied to learn how this information is used. This leads to two new interpolation algorithms for the green image. The red and blue interpolation algorithm of AH is also studied to determine how the inter-image correlation is used when interpolating these images. This study shows that because the green image is sampled at a higher rate, it retains much of the high-frequency information in the original image. This information is used to estimate aliasing in the red and blue images. We present a general algorithm based on the AH algorithm to interpolate the red and blue images. This algorithm is able to provide results that are on average, better than both reference algorithms, POCS and AH.
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Meersman, Kristof de. "Estimating signal polarisations in seismic array data : theory and applications." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422060.

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Luker, L. Dwight. "Investigation of a cylindrical nonacoustic-wavenumber calibration array." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15885.

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Chen, Chiao-En. "Theory and applications of parametric estimation methods for sensor array signal processing." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1666392601&sid=24&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Larocque, Jean-René. "Advanced bayesian methods for array signal processing /." *McMaster only, 2001.

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Zelnio, Anne M. "Detection of Small Aircraft using an Acoustic Array." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1247075795.

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Elbergali, Abdalla Kh. "Factor analysis : theory and applications to evolutionary problems in chemometrics." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282138.

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Mulholland, P. J. "Adaptive filters and their application to an adaptive receiving array for an underwater acoustic data link." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234508.

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Wood, Sean James. "Image quality of optical systems when used with focal plane array detectors." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384898.

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McCormick, A. H. I. "Application of the moment method to the design of slotted waveguide array antennas." Thesis, Heriot-Watt University, 1988. http://hdl.handle.net/10399/1962.

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Dogan, Doganay. "Dual Polarized Slotted Waveguide Array Antenna." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613016/index.pdf.

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An X band dual polarized slotted waveguide antenna array is designed with very high polarization purity for both horizontal and vertical polarizations. Horizontally polarized radiators are designed using a novel non-inclined edge wall slots whereas the vertically polarized slots are implemented using broad wall slots opened on baffled single ridge rectangular waveguides. Electromagnetic model based on an infinite array unit cell approach is introduced to characterize the slots used in the array. 20 by 10 element planar array of these slots is manufactured and radiation fields are measured. The measurement results of this array are in very good accordance with the simulation results. The dual polarized antenna possesses a low sidelobe level of -35 dB and is able to scan a sector of ±
35 degrees in elevation. It also has a usable bandwidth of 600 MHz.
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Ng, William Reilly James P. "Advances in wideband array signal processing using numerical Bayesian methods /." *McMaster only, 2003.

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Murthy, Vinay. "Recovery from transient faults in wavefront processor arrays." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06302009-040356/.

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Semsir, Emine Zeynep. "Adaptive Beam Control Of Dual Beam Phased Array Antenna System." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610695/index.pdf.

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In this study, the Dual Beam Phased Array Antenna System designed for COST260* project is upgraded to have the abilities of beam steering, tracking and direction finding by providing the necessary computer codes using C++ Programming Language. The functions of new prototype are tested to verify the operation. *COST260 project was an adaptive phased array receiving antenna system for satellite communication, which was operating at 11.49-11.678 GHz band.
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Porter, Christopher Douglas. "Topics in the Theory of Josephson Arrays and Disordered Magnetic Systems." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1315459079.

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Bouktache, Essaid. "Analysis of an adaptive antenna array with intermediate-frequency weighting partially implemented by digital processing /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260135357046.

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Schafer, Ingo. "Orthogonal and Nonorthogonal Expansions for Multi-Level Logic Synthesis for Nearly Linear Functions and their Application to Field Programmable Gate Array Mapping." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/1339.

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The growing complexity of integrated circuits and the large variety of architectures of Field Programmable Gate Arrays (FPGAs) require sophisticated logic design tools. In the beginning of the eighties the research in logic design was concentrated on the development of fast two-level AND-OR logic minimizers like the well known ESPRESSO. However, most logic functions have a smaller and often faster circuit realization as a multi-level circuit. Thus, synthesis tools emerged for the minimization of the circuit area in a multi-level realization. Most of these synthesis tools are based on the "unate paradigm". Therefore, the synthesis methods are only advantageous for functions having a minimal circuit realization based on AND-OR gates. However, many common functions have a minmal circuit realization having a mix of AND, OR and EXOR gates like counters, adders, multipliers, and parity generators. Therefore, the design of such functions with synthesis tools based on the "unated paradigm" is very inefficient. Circuits incorporating the EXOR gate have received less attention than AND-OR circuits because the EXOR gate was perceived as slower and larger in terms of its circuit realization than the AND and the OR gate. However, the upcoming of Field Programmable Gate Arrays (FPGAs) like the Xilinx Table-Look-Up (TLU) architecture the Actel ACTâ„¢ series and the CLi 6000 series from Concurrent Logic, which allow the realization of the EXOR gate with the same speed and circuit cost as the AND and OR gate, eliminates the disadvantages of the EXOR gate over the AND and OR gate. Thus, there is a strong need for logic synthesis tools that take advantage of EXOR gates. The mapping to the new FPGAs recently obtained an increased interest. The developed synthesis algorithms for FPGAs are based on the mapping and restructuring of the Directed Acyclic Graph (DAG) representation of the logic function. Even though the new FPGAs allow the realization of the EXOR gate without any speed and circuit size penalty in comparison to the AND and OR gate, the synthesis methods have been based on the "unate paradigm". To overcome the disadvantages of the current logic synthesis tools with respect to (nearly) linear functions and FPGA synthesis, this dissertation introduces an extended theory of spectral methods for multiple-valued input, incompletely specified binary output logic. The spectral methods have not been popular in logic synthesis because of their four major drawbacks: (1) the computational complexity, especially if no Fast Transform exists, (2) the memory requirement to store the function in the necessary minterm representation, (3) they cannot take efficiently advantage of incompletely specified functions, (4) suitable only for few applications in logic synthesis. To overcome the two last stated drawbacks, this dissertation introduces the T spectrum. The T spectrum separates the information obtained for the specified and not specified parts of the underlying function. Thus, it is possible to determine directly the contribution of the specified and the not specified part of the function to a single spectral coefficient. Moreover, the T spectrum is an extension of the known spectra like Walshtype, Adding, Arithmetic, and Reed-Muller spectra to any orthogonal and nonorthogonal transform describing logic functions. Thus, transforms can be constructed that describe certain gate structures, as for example the realizable functions of a FPGA macrocell. This allows the development of special synthesis algorithms for the different types of FPGA architectures. As an exemplification of this method, a complete multi-level synthesis algorithm is introduced for the circuit realization with multiplexer modules, which form the basic macrocell of the Actel ACfâ„¢ FPGA series. Additionally, this dissertation presents the classification of the applications of spectral methods in logic synthesis into three categories: (1) The decomposition of logic functions based on the information obtained by the computation of a single spectrum. As an example the linearization procedure developed by Karpowsky is generalized to incompletely specified multi-output Boolean functions. The linearization procedure is based on the computation of the Rademacher-Walsh spectrum with a following decomposition of the underlying function based on high value spectral coefficients. (2) The circuit realization of a logic function based on the repetitive application of (1). This synthesis method is exemplified by an multi-level synthesis algorithm for multiplexer gates. (3) The realization of a logic function as an AND-EXOR circuit based on a GF 2 (Galois Field (2)) spectrum. The GF 2 transforms exhibit the property that they describe a realization of the underlying function as a two-level AND-EXOR circuit. The Multiple-Valued Input Kronecker Reed-Muller (MIKRM) form is introduced as an application of GF 2 transforms. To overcome the drawbacks of spectral methods concerning the computational complexity and high memory requirements, this dissertation presents a computation method for spectra from disjoint representations. The introduced application of the disjoint cube representation and the Ordered Decision Diagrams for the computation of spectra proves to be an ideal concept. Thus, this dissertation presents general synthesis methods based on new spectral methods that overcome the deficiencies of current logic synthesis methods with respect to the synthesis for FPGAs as well as the computational complexity and memory requirements of spectral methods.
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Maltais, Elizabeth Jane. "Graph-dependent Covering Arrays and LYM Inequalities." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34434.

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The problems we study in this thesis are all related to covering arrays. Covering arrays are combinatorial designs, widely used as templates for efficient interaction-testing suites. They have connections to many areas including extremal set theory, design theory, and graph theory. We define and study several generalizations of covering arrays, and we develop a method which produces an infinite family of LYM inequalities for graph-intersecting collections. A common theme throughout is the dependence of these problems on graphs. Our main contribution is an extremal method yielding LYM inequalities for $H$-intersecting collections, for every undirected graph $H$. Briefly, an $H$-intersecting collection is a collection of packings (or partitions) of an $n$-set in which the classes of every two distinct packings in the collection intersect according to the edges of $H$. We define ``$F$-following" collections which, by definition, satisfy a LYM-like inequality that depends on the arcs of a ``follow" digraph $F$ and a permutation-counting technique. We fully characterize the correspondence between ``$F$-following" and ``$H$-intersecting" collections. This enables us to apply our inequalities to $H$-intersecting collections. For each graph $H$, the corresponding inequality inherently bounds the maximum number of columns in a covering array with alphabet graph $H$. We use this feature to derive bounds for covering arrays with the alphabet graphs $S_3$ (the star on three vertices) and $\kvloop{3}$ ($K_3$ with loops). The latter improves a known bound for classical covering arrays of strength two. We define covering arrays on column graphs and alphabet graphs which generalize covering arrays on graphs. The column graph encodes which pairs of columns must be $H$-intersecting, where $H$ is a given alphabet graph. Optimizing covering arrays on column graphs and alphabet graphs is equivalent to a graph-homomorphism problem to a suitable family of targets which generalize qualitative independence graphs. When $H$ is the two-vertex tournament, we give constructions and bounds for covering arrays on directed column graphs. FOR arrays are the broadest generalization of covering arrays that we consider. We define FOR arrays to encompass testing applications where constraints must be considered, leading to forbidden, optional, and required interactions of any strength. We model these testing problems using a hypergraph. We investigate the existence of FOR arrays, the compatibility of their required interactions, critical systems, and binary relational systems that model the problem using homomorphisms.
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Tran, Nguyen Duy. "Performance bounds in terms of estimation and resolution and applications in array processing." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00777503.

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This manuscript concerns the performance analysis in signal processing and consists into two parts : First, we study the lower bounds in characterizing and predicting the estimation performance in terms of mean square error (MSE). The lower bounds on the MSE give the minimum variance that an estimator can expect to achieve and it can be divided into two categories depending on the parameter assumption: the so-called deterministic bounds dealing with the deterministic unknown parameters, and the so-called Bayesian bounds dealing with the random unknown parameter. Particularly, we derive the closed-form expressions of the lower bounds for two applications in two different fields: (i) The first one is the target localization using the multiple-input multiple-output (MIMO) radar in which we derive the lower bounds in the contexts with and without modeling errors, respectively. (ii) The other one is the pulse phase estimation of X-ray pulsars which is a potential solution for autonomous deep space navigation. In this application, we show the potential universality of lower bounds to tackle problems with parameterized probability density function (pdf) different from classical Gaussian pdf since in X-ray pulse phase estimation, observations are modeled with a Poisson distribution. Second, we study the statistical resolution limit (SRL) which is the minimal distance in terms of the parameter of interest between two signals allowing to correctly separate/estimate the parameters of interest. More precisely, we derive the SRL in two contexts: array processing and MIMO radar by using two approaches based on the estimation theory and information theory. We also present in this thesis the usefulness of SRL in optimizing the array system.
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26

Polat, Ozgur Murat. "Ray Anlaysis Of Electromagnetic Scattering From Semi-infinite Array Of Dipoles In Free Space." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608347/index.pdf.

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Electromagnetic wave scattering from a semi-infinite array of dipoles in free space is described by using asymptotic high frequency methods. An electric field integral expression is obtained and solved with asymptotic high frequency methods. An asymptotic field expression is obtained for a finite ×
infinite array of dipoles in free space. The analytical closed form expression for the array guided surface wave launching coefficient is obtained via a combination of an asymptotic high frequency analysis of a related reciprocal problem and Lorentz reciprocity integral formulation for the semi-infinite planar dipole array in which modified Kirchhoff approximation is used. The accuracy and the validity of the asymptotic analytical solutions are compared with the numerical solutions available in the literature before.
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27

Yoon, Sungsoo. "Array-Based Measurements of Surface Wave Dispersion and Attenuation Using Frequency-Wavenumber Analysis." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7246.

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Surface wave methods have been used to determine dynamic properties of near-surface soils in geotechnical engineering for the past 50 years. Although the capabilities of engineering surface wave methods have improved in recent years due to several advances, several issues including (1) near-field effects, (2) combined active and passive measurements, and (3) accurate measurements of surface wave attenuation still require study to further improve the capabilities of modern surface wave methods. Near-field effects have been studied for traditional surface wave methods with two receivers and several filtering criteria to mitigate the effects have been recommended. However, these filtering criteria are not applicable to surface wave methods with multiple receivers. Moreover, the criteria are not quantitatively based and do not account for different types of soil profiles, which strongly influence near-field effects. A new study of near-field effects on surface wave methods with multiple receivers was conducted with numerical and experimental methods. Two normalized parameters were developed to capture near-field effects. Quantitatively based near-field effect criteria for an ideal homogeneous half-space and three typical soil profiles are presented. Combining active and passive surface wave measurements allows developing a shear wave velocity profile to greater depth without sacrificing the near-surface resolution offered by active measurements. Generally, active and passive measurements overlap in the frequency range from approximately 4 to 10 Hz, and there are often systematic differences between the two measurements. The systematic errors in active and passive surface wave methods were explored to explain and resolve the differences, allowing for a more accurate composite dispersion curve. The accuracy of measured surface wave attenuation is improved by properly accounting for (1) geometric spreading, (2) near-field effects, and (3) ambient noise. In this study, a traditional estimation method and a frequency-wavenumber method utilizing sub-arrays were investigated using displacement data from numerical simulations, focusing on near-field and ambient noise effects. Detailed procedures for the frequency-wavenumber estimation method are developed based on a study of the primary factors affecting attenuation estimates. The two methods are also evaluated using experimental displacement data obtained from surface wave field measurements with three different arrays.
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Siverns, James D. "Yb ion trap experimental set-up and two-dimensional ion trap surface array design towards analogue quantum simulations." Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/43344/.

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Ions trapped in Paul traps provide a system which has been shown to exhibit most of the properties required to implement quantum information processing. In particular, a two-dimensional array of ions has been shown to be a candidate for the implementation of quantum simulations. Microfabricated surface geometries provide a widely used technology with which to create structures capable of trapping the required two-dimensional array of ions. To provide a system which can utilise the properties of trapped ions a greater understanding of the surface geometries which can trap ions in two-dimensional arrays would be advantageous, and allow quantum simulators to be fabricated and tested. In this thesis I will present the design, set-up and implementation of an experimental apparatus which can be used to trap ions in a variety of different traps. Particular focus will be put on the ability to apply radio-frequency voltages to these traps via helical resonators with high quality factors. A detailed design guide will be presented for the construction and operation of such a device at a desired resonant frequency whilst maximising the quality factor for a set of experimental constraints. Devices of this nature will provide greater filtering of noise on the rf voltages used to create the electric field which traps the ions which could lead to reduced heating in trapped ions. The ability to apply higher voltages with these devices could also provide deeper traps, longer ion lifetimes and more efficient cooling of trapped ions. In order to efficiently cool trapped ions certain transitions must be known to a required accuracy. In this thesis the 2S1/2 → 2P1/2 Doppler cooling and 2D3/2 → 2D[3/2]1/2 repumping transition wavelengths are presented with a greater accuracy then previous work. These transitions are given for the 170, 171, 172, 174 and 176 isotopes of Yb+. Two-dimensional arrays of ions trapped above a microfabricated surface geometry provide a technology which could enable quantum simulations to be performed allowing solutions to problems currently unobtainable with classical simulation. However, the spin-spin interactions used in the simulations between neighbouring ions are required to occur on a faster time-scale than any decoherence in the system. The time-scales of both the ion-ion interactions and decoherence are determined by the properties of the electric field formed by the surface geometry. This thesis will show how geometry variables can be used to optimise the ratio between the decoherence time and the interaction time whilst simultaneously maximising the homogeneity of the array properties. In particular, it will be shown how the edges of the geometry can be varied to provide the maximum homogeneity in the array and how the radii and separation of polygons comprising the surface geometry vary as a function of array size for optimised arrays. Estimates of the power dissipation in these geometries will be given based on a simple microfabrication.
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Sheikh, Muhammad Hassan. "Time-Modulated Array Co-Simulation with the Aid of Commercial Software." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13957/.

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This thesis report exhibits an integrated Electromagnetic/Circuit level technique to analyze the time modulated arrays. I restate this work in commercial software which was already developed in CAD domain i.e. combining the exact harmonic balanced based analysis of non-linear switches with the electromagnetic characterization of the radiating elements. In this commercial software I try to perform a full-wave co-simulation to compute the radiated far-field envelope to show the array behavior. Simulation in this new software allows a precise evaluation of several non-linear performance aspects of the radiating system, such as power usage capabilities and the switch modulation frequency boundary. Secondly I also discuss a TMA wireless power transfer technique which is based on two step procedure. In this case I carry out the full wave co-simulation in this new commercial software to analyze the antenna array with modulated non-linear feeding network. Schottky-diode based network provide proper modulated RF excitations of the array elements. Therefore, the array architecture is extremely simple, if compared to phased arrays, only simple control circuit board.
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30

Tendero, Yohann. "Mathematical theory of the Flutter Shutter : its paradoxes and their solution." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00752409.

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This thesis provides theoretical and practical solutions to two problems raised by digital photography of moving scenes, and infrared photography. Until recently photographing moving objects could only be done using short exposure times. Yet, two recent groundbreaking works have proposed two new designs of camera allowing arbitrary exposure times. The flutter shutter of Agrawal et al. creates an invertible motion blur by using a clever shutter technique to interrupt the photon flux during the exposure time according to a well chosen binary sequence. The motion-invariant photography of Levin et al. gets the same result by accelerating the camera at a constant rate. Both methods follow computational photography as a new paradigm. The conception of cameras is rethought to include sophisticated digital processing. This thesis proposes a method for evaluating the image quality of these new cameras. The leitmotiv of the analysis is the SNR (signal to noise ratio) of the image after deconvolution. It gives the efficiency of these new camera design in terms of image quality. The theory provides explicit formulas for the SNR. It raises two paradoxes of these cameras, and resolves them. It provides the underlying motion model of each flutter shutter, including patented ones. A shorter second part addresses the the main quality problem in infrared video imaging, the non-uniformity. This perturbation is a time-dependent noise caused by the infrared sensor, structured in columns. The conclusion of this work is that it is not only possible but also efficient and robust to perform the correction on a single image. This permits to ensure the absence of ''ghost artifacts'', a classic of the literature on the subject, coming from inadequate processing relative to the acquisition model.
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31

Garcia, Fábio Lumertz 1979. "Implementação de codificador LDPC para um sistema de TV digital usando ferramentas de prototipagem rapida." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258896.

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Orientadores: Dalton Soares Arantes, Fabbryccio A. Cardoso
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-08T03:13:26Z (GMT). No. of bitstreams: 1 Garcia_FabioLumertz_M.pdf: 3287022 bytes, checksum: 7cf0e283ddc5a0d2f929f3cc22b17903 (MD5) Previous issue date: 2006
Resumo: O objetivo deste trabalho é apresentar as diversas etapas de implementação de um codificador LDPC para um sistema de televisão digital, desenvolvido através do emprego de algumas tecnologias inovadoras de prototipagem rápida em FPGA. O codificador implementado foi baseado em um código LDPC eIRA, que consiste em uma classe estendida de códigos de repetição e acumulação irregulares, com palavra-código de 9792 bits e taxa de 3/4. Visando agregar outras tecnologias emergentes ao projeto de TV Digital, o sistema proposto foi desenvolvido para operar sobre o Protocolo de Internet - IP. Os esforços para a realização deste trabalho fizeram parte de um esforço mais amplo de um consórcio de universidades brasileiras, visando à concepção, ao projeto, à simulação e à implementação em hardware de um Sistema de Modulação Inovadora para o SBTVD. A grande sinergia obtida neste projeto e o uso intensivo de ferramentas de prototipagem rápida em FPGA possibilitaram a obtenção de uma prova de conceito implementada e testada em um prazo de apenas 12 meses
Abstract: This work presents the several phases in the implementation of an LDPC encoder for a digital television system, developed using innovative technologies for rapid prototyping on Field Programmable Gate Array devices - FPGAs. The implemented encoder was based on an eIRA - extended Irregular Repeat Accumulate - LDPC code with codeword-Iength equal to 9792 bits and rate 3/4. The proposed system was developed to work with video streaming over the Internet Protocol- IP. This work is part of a more ambitious project that resulted in the development of an advanced Modulation System for the Brazilian Digital TV System - BTVD
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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32

Giuliani, Chiara. "Alteration of ocean waves by periodic submerged structures for renewable energy extraction." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

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Questa tesi si concentra sul comportamento di strutture immerse e sulla loro interazione con fenomeni ondosi oceanici allo scopo di modificarne l’ampiezza in superficie. Si suppone che queste strutture siano disposte sul fondale marino secondo schemi geometrici ricorrenti, per esempio lenti. Opportune disposizioni strutturali possono indurre un’interferenza costruttiva sulle onde di superficie, le quali presentano tipicamente un carattere pseudo-periodico nel tempo e nello spazio aumentandone così l’ampiezza. Noto che l’energia delle onde di superficie è proporzionale alla loro ampiezza, i risultati proposti in questa ricerca possono essere utilizzati per migliorare, in maniera del tutto sostenibile, l’efficienza dei dispositivi che sfruttano il moto ondoso per l’estrazione di energia rinnovabile, anche noti come energy harvesters. Per questi ultimi infatti l’efficienza della conversione dell’energia dipende dalla variazione altimetrica fra la cresta e il ventre dell’onda. Nello studio del problema, si considereranno le equazioni classiche di Navier-Stokes applicate al caso di fondali medio bassi (shallow waters). Successivamente teorie complesse per lo studio di sistemi periodici (già utilizzate in altri campi come la fisica quantistica e l’elettromagnetismo), verranno applicate per descrivere l’interazione tra le onde e il fondale periodico. Tale formulazione consentirà di progettare le strutture sul fondale capaci ottimizzare l’ampiezza dell’onda rispetto al caso di fondale indisturbato.
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33

Wijaya, Shierly. "Fixed-point realisation of erbium doped fibre amplifer control algorithms on FPGA." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0132.

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The realisation of signal processing algorithms in fixed-point offers substantial performance advantages over floating-point realisations. However, it is widely acknowledged that the task of realising algorithms in fixed-point is a challenging one with limited tool support. This thesis examines various aspects related to the translation of algorithms, given in infinite precision or floating-point, into fixed-point. In particular, this thesis reports on the implementation of a given algorithm, an EDFA (Erbium-Doped Fibre Amplifier) control algorithm, on a FPGA (Field Programmable Gate Array) using fixed-point arithmetic. An analytical approach is proposed that allows the automated realisation of algorithms in fixedpoint. The technique provides fixed-point parameters for a given floating-point model that satisfies a precision constraint imposed on the primary output of the algorithm to be realised. The development of a simulation framework based on this analysis allows fixed-point designs to be generated in a shorter time frame. Albeit being limited to digital algorithms that can be represented as a data flow graph (DFG), the approach developed in the thesis allows for a speed up in the design and development cycle, reduces the possibility of error and eases the overall effort involved in the process. It is shown in this thesis that a fixed-point realisation of an EDFA control algorithm using this technique produces results that satisfy the given constraints.
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34

Schürmann, Klaus-Bernd. "Suffix arrays in theory and practice." [S.l.] : [s.n.], 2007. http://bieson.ub.uni-bielefeld.de/volltexte/2007/1179/index.html.

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35

Khoi, Nguyen Trong. "Couplage d'ondes pour le chauffage des plasmas à la fréquence hybride basse." Grenoble INPG, 1986. http://www.theses.fr/1986INPG0016.

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La theorie lineaire et quasi-lineaire de la propagation des ondes au voisinage de la frequence hybride inferieure et de leur interaction avec les particules du plasma est utilisee pour determiner les parametres et le dimensionnement des coupleurs d'ondes lentes dans les trois applications principales : chauffage des ions, chauffage des electrons et generation de courant. Le tenseur dielectrique "plasma froid" est utilise pour determiner l'admittance de surface plasma qui represente la charge de l'antenne et conditionne son efficacite
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36

Wood, John Jesse. "Theory of surface modes in structured plasmonic arrays." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/45355.

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Metamaterials can provide many different functionalities and striking optical properties, whereby the optical control often comes from metallic building blocks which exhibit plasmonic resonances in the optical and infra-red frequency regimes. However, one of the major obstacles in the use of metallic elements is the overcoming of the losses in plasmonic structures. In this thesis, we consider how mode hybridisation can be used to circumvent these losses using cut-wire plasmonic arrays coupled to photonic slab waveguides. The resulting hybrid modes can have low loss characteristics and we investigate how the geometric parameters of the structure can be used to control the transmission and dispersion properties. We then investigate finite arrays finding they can support modes with extremely high quality factors (Q∼ 4000), which is highly unusual in plasmonic systems, and that the individual loss mechanisms can be controlled via the geometry. In the second part of the thesis we consider another type of surface mode, the spoof SPP. Theoretical methods for describing spoof SPPs in perfectly conducting materials are well established, enabling the design of an arbitrary spoof plasma frequency. However, for dispersive materials there have been a lack of theoretical studies. We begin by considering first how small changes to the spoof plasmon geometry affect the characteristics of spoof SPP waves, adapting the coupled mode method to slanted geometries and even right-angled triangular indentations, a structure not normally associated with spoof SPPs. We then develop a formalism based on the coupled mode method allowing the dispersion of real metal spoof SPPs to be understood and tuned, thus enabling control of the optical spoof SPP characteristics via both the geometry and the incorporated materials. This method also enables an in depth look at the modal losses which occur once dispersive materials are incorporated into the spoof plasmon dispersion relation and vary drasticallywith the groove width.
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37

Peiffer, Benjamin Michael. "Theory and implementation of scalable, retrodirective distributed arrays." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/6833.

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A Distributed Multi-Input Multi-Output (DMIMO) system consists of many transceivers coordinating themselves into a "virtual antenna array" in order to emulate MIMO capabilities. In recent years, the field of research investigating DMIMO Communications has grown substantially. DMIMO systems offer all of the same benefits of standard MIMO systems on a larger scale because arrays are not limited by the physical constraint of placing many antennas on a single transceiver. This additional benefit does come at a cost, however. Since nodes are distributed and run from independent clock signals and with unknown geometry, each one must its own obtain channel state information (CSI) to the target nodes. In existing DMIMO architectures, array nodes depend on feedback from target nodes to properly synchronize. This means that target nodes must be cooperative and are responsible for the overhead calculating and transmitting CSI feedback to each node in the array. Within this work, we develop a set of techniques for Retrodirective Distributed Antenna Arrays. Retrodirective arrays have traditionally been used to direct a beam towards a target node, but the work in this thesis seeks to develop a more generalized definition of retrodirectivity. By our definition, a retrodirective array is one that acquires CSI to one or more intended targets simply by listening to the incoming transmissions of those targets; the array may subsequently use this information to do any number of typical MIMO tasks (i.e., beamforming, nullforming, spatial multiplexing, etc.). We explore two primary techniques: i) distributed beamforming and ii) distributed nullforming. Beamforming involves focusing transmitted power towards a specific target node and nullforming involves directing transmissions of array nodes to cancel one another at a specific target node. We focus on these techniques because they can be thought of as basic building blocks for more sophisticated DMIMO techniques. We first develop the theory for retrodirective arrays. Then, we present an architecture for the implementation of this theory. Specifically, we focus on the pre-synchronization of the array, which involves use of a master/slave architecture and a timeslotted message exchange among the array nodes. Finally, developing algorithms to make these arrays both robust and scalable is the focus of this thesis.
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Ait-Boudaoud, Djamel. "Novel cell architectures for systolic signal processing arrays." Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334976.

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39

Elgayar, Saad M. "From Theory to Practice: Randomly Sampled Arrays for Passive Radar." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503304471335023.

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40

Mandal, Abhyuday. "Some Contributions to Design Theory and Applications." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7142.

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The thesis focuses on the development of statistical theory in experimental design with applications in global optimization. It consists of four parts. In the first part, a criterion of design efficiency, under model uncertainty, is studied with reference to possibly nonregular fractions of general factorials. The results are followed by a numerical study and the findings are compared with those based on other design criteria. In the second part, optimal designs are dentified using Bayesian methods. This work is linked with response surface methodology where the first step is to perform factor screening, followed by response surface exploration using different experiment plans. A Bayesian analysis approach is used that aims to achieve both goals using one experiment design. In addition we use a Bayesian design criterion, based on the priors for the analysis approach. This creates an integrated design and analysis framework. To distinguish between competing models, the HD criterion is used, which is based on the pairwise Hellinger distance between predictive densities. Mixed-level fractional factorial designs are commonly used in practice but its aliasing relations have not been studied in full rigor. These designs take the form of a product array. Aliasing patterns of mixed level factorial designs are discussed in the third part. In the fourth part, design of experiment ideas are used to introduce a new global optimization technique called SELC (Sequential Elimination of Level Combinations), which is motivated by genetic algorithms but finds the optimum faster. The two key features of the SELC algorithm, namely, forbidden array and weighted mutation, enhance the performance of the search procedure. Illustration is given with the optimization of three functions, one of which is from Shekel's family. A real example on compound optimization is also given.
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Fisher, Kent. "Topics in the theory of periodic composites and Josephson Junction Arrays /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488192447431305.

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42

Meagher, Karen. "Covering arrays on graphs: Qualitative independence graphs and extremal set partition theory." Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/29234.

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There has been a good deal of research on covering arrays over the last 20 years. Most of this work has focused on constructions, applications and generalizations of covering arrays. The main focus of this thesis is a generalization of covering arrays, covering arrays on graphs. The original motivation for this generalization was to improve applications of covering arrays to testing systems and networks, but this extension also gives us new ways to study covering arrays. Two vectors v, w in Znk are qualitatively independent if for all ordered pairs (a, b) ∈ Zk x Zk there is a position i in the vectors where ( a, b) = (vi, w i). A covering array is an array with the property that any pair of rows are qualitatively independent. A covering array on a graph is an array with a row for each vertex of the graph with the property that any two rows which correspond to adjacent vertices are qualitatively independent. A covering array on the complete graph is a covering array. A covering array is optimal if it has the minimum number of columns among covering arrays with the same number of rows. The addition of a graph structure to covering arrays makes it possible to use methods from graph theory to study these designs. In this thesis, we define a family of graphs called the qualitative independence graphs . A graph has a covering array, with given parameters, if and only if there is a homomorphism from the graph to a particular qualitative independence graph. Cliques in qualitative independence graphs relate to covering arrays and independent sets are connected to intersecting partition systems. It is known that the exact size of an optimal binary covering array can be determined using Sperner's Theorem and the Erdős-Ko-Rado Theorem. In this thesis, we find good bounds on the size of an optimal binary covering array on a graph. In addition, we determine both the chromatic number and a core of the binary qualitative independence graphs. Since the rows of general covering arrays correspond to set partitions, we give extensions of Sperner's Theorem and the Erdős-Ko-Rado Theorem to set-partition systems. These results are part of a general framework to study extremal partition systems. The core of the binary qualitative independence graphs can be generalized to a subgraph of a general qualitative independence graph called the uniform qualitative independence graph. Cliques in the uniform qualitative independence graphs relate to balanced covering arrays. Using these graphs, we find bounds on the size of a balanced covering array. We give the spectra for several of these graphs and conjecture that they are graphs in an association scheme. We also give a new construction for covering arrays which yields many new upper bounds on the size of optimal covering arrays.
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43

Arras, Philipp Adam [Verfasser], and Torsten [Akademischer Betreuer] Enßlin. "Radio interferometry with information field theory / Philipp Adam Arras ; Betreuer: Torsten Enßlin." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1233966928/34.

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44

Chen, Haihua, and 陳海華. "Uniform concentric circular and spherical arrays with frequency invariant characteristics: theory, design andapplications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37474005.

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45

Krishnamurthy, Siddhartha. "Peak Sidelobe Level Distribution Computation for Ad Hoc Arrays using Extreme Value Theory." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11300.

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Extreme Value Theory (EVT) is used to analyze the peak sidelobe level distribution for array element positions with arbitrary probability distributions. Computations are discussed in the context of linear antenna arrays using electromagnetic energy. The results also apply to planar arrays of random elements that can be transformed into linear arrays.
Engineering and Applied Sciences
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46

McCoy, E. "New modelling applications for Helmholtz soliton theory : from single interfaces to waveguide arrays." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/32104/.

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This thesis details an exploration of the behaviour of spatial optical solitons (self-collimated, self-stabilising light beams) interacting with the interface between classes of nonlinear dielectric materials. Chapter 1 gives the theoretical background to the thesis by introducing the soliton concept, material interfaces and the Helmholtz model. The second chapter discusses the reflection and refraction characteristics of soliton beams incident on the planar boundary between dissimilar cubic-quintic materials. The deployment of Helmholtz soliton theory allows for the simultaneous consideration of: (i) arbitrary angles of incidence, reflection and refraction (relative to the interface), and (ii) finite beam waists (as opposed to infinitely-wide plane waves). Despite an abundance of literature concerning solitons at interfaces, there appears to be no published research addressing refraction in the presence of cubic-quintic optical nonlinearity (and certainly none in arbitrary-angle contexts). Excellent agreement is generally found between theoretical predictions from a generalised Snell’s law and results from extensive computer simulations. In Chapter 3, these novel analyses have been complemented by further investigations into other fundamental aspects of optical refraction, namely Goos-Hänchen shifts and critical angle prediction. Both aspects are the first of their kind in the cubic-quintic regime. The fourth chapter considers surface wave propagation along the interface between two dissimilar power-law materials; this research has already contributed to a published peer reviewed paper [J. M. Christian et al., "Helmholtz bright spatial solitons and surface waves at power-law optical interfaces," Journal of Atomic, Molecular & Optical Physics 2012 (2012), art. no. 137967]. The chapter also expands upon that paper by giving a more detailed account of surface wave stability properties. Chapter 5 provides an in-depth computational study into beam propagation in coupled waveguide arrays (materials whose refractive index is periodically patterned) and there appears to be a link between the beam's critical angle and the depth of the modulation of the array. The thesis concludes with a summary of findings and suggestions surrounding the implications of this novel research.
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47

Kalaydjiyski, Ludmil Borissov. "Fully connected transputer arrays for fault-tolerant real-time control." Thesis, Staffordshire University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293332.

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48

Chen, Haihua. "Uniform concentric circular and spherical arrays with frequency invariant characteristics theory, design and applications /." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37474005.

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49

Liu, Alice Weimin. "Viscoelastic flow of polymer solutions around arrays of cylinders : comparison of experiment and theory." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10409.

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50

Combernoux, Alice. "Détection et filtrage rang faible pour le traitement d'antenne utilisant la théorie des matrices aléatoires en grandes dimensions." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC016/document.

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Partant du constat que dans plus en plus d'applications, la taille des données à traiter augmente, il semble pertinent d'utiliser des outils appropriés tels que la théorie des matrices aléatoires dans le régime en grandes dimensions. Plus particulièrement, dans les applications de traitement d'antenne et radar spécifiques STAP et MIMO-STAP, nous nous sommes intéressés au traitement d'un signal d'intérêt corrompu par un bruit additif composé d'une partie dite rang faible et d'un bruit blanc gaussien. Ainsi l'objet de cette thèse est d'étudier dans le régime en grandes dimensions la détection et le filtrage dit rang faible (fonction de projecteurs) pour le traitement d'antenne en utilisant la théorie des matrices aléatoires.La thèse propose alors trois contributions principales, dans le cadre de l'analyse asymptotique de fonctionnelles de projecteurs. Ainsi, premièrement, le régime en grandes dimensions permet ici de déterminer une approximation/prédiction des performances théoriques non asymptotiques, plus précise que ce qui existe actuellement en régime asymptotique classique (le nombre de données d'estimation tends vers l'infini à taille des données fixe). Deuxièmement, deux nouveaux filtres et deux nouveaux détecteurs adaptatifs rang faible ont été proposés et il a été montré qu'ils présentaient de meilleures performances en fonction des paramètres du système en terme de perte en RSB, probabilité de fausse alarme et probabilité de détection. Enfin, les résultats ont été validés sur une application de brouillage, puis appliqués aux traitements radar STAP et MIMO-STAP sparse. L'étude a alors mis en évidence une différence notable avec l'application de brouillage liée aux modèles de matrice de covariance traités dans cette thèse
Nowadays, more and more applications deal with increasing dimensions. Thus, it seems relevant to exploit the appropriated tools as the random matrix theory in the large dimensional regime. More particularly, in the specific array processing applications as the STAP and MIMO-STAP radar applications, we were interested in the treatment of a signal of interest corrupted by an additive noise composed of a low rang noise and a white Gaussian. Therefore, the aim of this thesis is to study the low rank filtering and detection (function of projectors) in the large dimensional regime for array processing with random matrix theory tools.This thesis has three main contributions in the context of asymptotic analysis of projector functionals. Thus, the large dimensional regime first allows to determine an approximation/prediction of theoretical non asymptotic performance, much more precise than the literature in the classical asymptotic regime (when the number of estimation data tends to infinity at a fixed dimension). Secondly, two new low rank adaptive filters and detectors have been proposed and it has been shown that they have better performance as a function of the system parameters, in terms of SINR loss, false alarm probability and detection probability. Finally, the results have been validated on a jamming application and have been secondly applied to the STAP and sparse MIMO-STAP processings. Hence, the study highlighted a noticeable difference with the jamming application, related to the covariance matrix models concerned by this thesis
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