Bibliography: leaves 287-294. This thesis addresses preprocessing issues for radar target classification from high resolution radar imagery. High resolution radar imagery of real aircraft in flight and of a MIRAGE aircraft on a turntable is examined. An algorithm to coherently average high resolution range profile is proposed.

Esta investigación está conducida a la resolución del problema de encontrar soluciones rentables para el despliegue de redes de fibra hasta el hogar (Fibre to the Home - FTTH). En una red de FTTH, el equipo transmisor-receptor de usuario así como el despliegue de la fibra en la llamada 'última milla' son las barreras principales. Una topología que consiste en hacer llegar una única fibra para dirigirse a cada usuario reduce la cantidad de fibra requerida. Por otro lado, los componentes ópticos pasivos alivian los requisitos de mantenimiento de la red de acceso. El efecto del backscattering de Rayleigh se ha identificado como la interferencia más crítica de este tipo de transmisión, el efecto sobre el funcionamiento del sistema y las investigaciones de posibles soluciones al mencionado problema son centro de estudio de esta tesis. Los experimentos realizados, revelan que, a pesar de la interferencia causada por del effecto Rayleigh no se puede eliminar totalmente, hay diferentes técnicas capaces de atenuar dicho efecto. El uso de los amplificadores ópticos semiconductores para implementar las funciones de transmisión-recepción agrega simplicidad al diseño de red en términos de transparencia de la longitud de onda y gracias a las capacidades de la amplificación de esta familia de dispositivos.Los resultados experimentales presentaron en este trabajo demuestran con éxito la modulación y la detección a 1Gbit/s y 2.5Gbit/s con los dispositivos basados en semiconductores, en enlaces de hasta 30km e incluso de hasta 50km de longitud. Nuevos prototipos son potencialmente capaces de transmitir a 10Gbit/s. Estructuras reflectoras basadas en amplificadores ópticos semiconductores reflectores son los candidatos mas adecuados.Éstos, realizan funciones de transmisión eficientemente y proporcionan la amplificación adecuada. Sin embargo, es necesario el diseño de nuevos diseños capaces de transmitir datos a una velocidad mayor. Una estrategia de comunicación bidireccional mediante una única fibra es la arquitectura más interesante los términos de reducción de costes por usuario (CAPEX). Por estos motivos, la ONU se convierte en un elemento clave en redes de acceso y un área muy interesante de investigación. Para una evolución exitosa de FTTH el diseño de la unidad de red debe ser simple, robusto, flexible y bajo coste para el cliente final. La traducción de los requisitos anteriormente mencionados en especificaciones técnicas establece las pautas siguientes para el diseño del FTTH ONU- Una única fibra por cada usuario para reducir tamaño de la red de acceso- Independencia de la longitud de onda para permitir una operación transparente en redes WDM- Que no haya fuente de luz activa en las dependencias de usuario para prevenir el mantenimiento en el lado del usuario- Con amplificación y así poder aumentar el número de usuarios y alcanzar mayores distanciasDe esta manera, el objetivo principal de esta tesis es la investigación de unidades ópticas de red reflectoras, especialmente las basadas en amplificadores ópticos de semiconductor, así como su funcionamiento en redes de FTTH, basadas en tecnología de acceso WDM-PON. Esto implica fundamentalmente- Identificar arquitecturas y dispositivos propuestos por medio de la investigación del trabajo publicado relacionado y destacar limitaciones y requisitos de los sistemas actuales- evaluar las diversos alternativas para la ONU y para proponer soluciones mejoradas, demostradas con simulaciones y experimentos - investigar limitaciones posibles de los sistemas transmisión bidireccionales y desarrollar soluciones para la mejora de la transmisión- desarrollar descripciones analíticas de las señales implicadas en la transmisión / This research was conducted to deal with the problem of finding cost-effective solutions for Fibre-to-the-Home (FTTH) network deployment. In the FTTH network, the transceiver at the user premises and the deployment of fibre at the last mile are the major barriers. A single-fibre topology to address each user reduces the amount of fibre required; passive optical components alleviate maintenance requirements in the access network.The Rayleigh backscattering effect is identified as the most critical crosstalk in such transmission, the effect on the system performance and the investigations of possible solutions are presented in this thesis. The studies reveal that despite the Rayleigh backscattering crosstalk can not be totally eliminated, several techniques can mitigate the effect.The use of the semiconductor optical amplifiers to feature transceiver tasks at the user premises adds simplicity to the network design in terms of wavelength transparency and amplification capabilities. We propose implementations with semiconductor amplifiers and test modulation and detection potentials inside the optical network. The experimental results successfully demonstrate modulation and detection at 1Gbit/s and 2.5Gbit/s with semiconductor-based devices, in links of 30km and even though of 50km length; bit rate of 10Gbit/s is feasible with novel prototypes as well. Reflective structures based on reflective semiconductor optical amplifiers are potential candidates, as they perform transmission functions efficiently and provide adequate amplification however, it is necessary the design of further structures capable of transmitting at a higher bit rates.

Since the inception of the backscatter-radio technology, this field has continually evolved. As a result, this technology is used for a multitude of applications like personnel identification, logistics and assets management and military purposes etc. Radio Frequency Identification (RFID) technology works in several ISM-frequency bands. This work pertains to the design and development of an RF tag that uses 5.8 GHz ISM band for backscatter. This frequency band has many inherent advantages like higher gain antennas, smaller sized tags, increased immunity to conductive object losses, and larger RF bandwidth. The objective of this research is design and prototype development of an RF tag capable of sensing acceleration, angular motion, and shock experienced by an object on which it is installed. The sensed information is modulated onto an incident continuous wave (CW) and backscattered to the reader. Literature research suggested that such work has not been done previously using an RFID platform. The challenges include integration of the sensor, antenna and other electronics to efficiently backscatter the information to the receiver, designing a suitable planar antenna, realtime backscattering of the sensed information, and low power consumption. As a further step, it is required to design and integrate two antennas on RF tag to simultaneously backscatter the same information; and to measure and compare its effect with single antenna tag. The sensed impact/shock and rotational movement information from the inertial sensors (accelerometer and gyroscope) was backscattered instantly and displayed on the custom developed graphical user interface. The development of GUI was not part of this project and was developed by another lab member. RF Tags with single and dual antenna configurations were designed and tested. It was observed that by increasing the number of antennas higher read range can be achieved. Moreover, by doubling the antennas the radar cross-section for the tag was approximately doubled.

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No description available.

At the Tandem accelerator in the Ångström laboratory, Uppsala, Rutherford backscattering spectrometry (RBS) is one of the methods used for thin film analysis, providing information on thickness and composition. The films are commonly grown on silicon substrates, whose crystal structure gives rise to channelling effects (a strong angular dependence in the intensity of the signal), which can cause faulty results. For other samples, channelling may also be used to get information on crystal structure and quality. This work demonstrates new functions to the existing software, aiming at minimizing these effects. The new methods have been tested by measurements both in channelling directions and in directions determined by the old method. In comparison with the earlier method the worst-case error is of order 80 %,commonly around 20 %, but it is possible to achieve an error which is not detectable. It is worth to note that the stated errors appear in tests oriented for maximum channelling, where effects without the new methods give an error corresponding to an apparent thin-film thickness almost 18 times that of the actual thickness. / Vid Tandemlabbet i Ångströmlaboratoriet, Uppsala, används bland annat Rutherford backscattering spectrometry (RBS) för att undersöka egenskaper, t.ex tjocklek och sammansättning, hos tunnfilmer som ofta är odlade på kiselsubstrat. Kiselkristallernas struktur ger upphov till kanaliseringseffekter, d.v.s starkt vinkelberoende intensitet, som i detta sammanhang kan ge felaktiga resultat. För andra prover kan kanaliseringseffekter användas för att få information om kristallstruktur och kvalitet. I det här arbetet demonstreras nyskrivna funktioner till befintlig mjukvara med syfte att minimera dessa effekter. De nya funktionerna har testats genom provtagningar i orienteringar som är gynnsamma och icke gynnsamma för kanalisering. Vid jämförelse med tidigare metoder ger de nya metoderna ett fel på i värsta fall ca. 80%, med bättre parametrar sjunker felet till ca 20 % och med rätt val av parametrar försvinner felet jämfört med tidigare metod. Värt att notera är att ovanstående maximala fel uppstår vid test orienterat för maximal kanalisering, där effekterna utan de nya metoderna ger ett fel på uppemot en faktor 18.

A primary goal of this thesis has been to demonstrate that stable, useful measurements of the orientation of the acoustic signal vector as a function of range and time can be obtained from ocean backscatter, and that this orientation, or acoustic phase, can be related to the local sound speed distribution. Such a measurement is quite distinct from the related problem of detecting the rate of phase change, which forms the basis of Doppler technology. Doppler measurements can be made using echoes from a single point, or a sparsely distributed set of targets. Consistent and useful measurement of absolute phase, is inherently more difficult, since it depends upon the positions of individual scatterers, which are normally random and sparse relative to the acoustic wavelength. / Graduate

Bibliography: leaves 287-294. / xviii, 294 p. : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis addresses preprocessing issues for radar target classification from high resolution radar imagery. High resolution radar imagery of real aircraft in flight and of a MIRAGE aircraft on a turntable is examined. An algorithm to coherently average high resolution range profile is proposed. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1995

Thesis (Ph. D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1995? / Includes bibliographical references (leaves 287-294).

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (p. [81]-83).