Abstract: This thesis is concerned with the acquisition of body signals using a sampling system. A typical application is the recording of the electrocardiogram (ECG). It is proposed to sample the input signal at different rates, depending on the momentary signal content. If the input signal has large voltage variation, it is sampled at a high rate. During periods of small variation, the signal is sampled at a lower frequency to save both memory and power. An analog controller to control the clock rate is proposed and implemented. The analog controller decides the sample frequency (high rate or low rate) depending on the input signal. The analysis of the proposed system is presented in this thesis. Furthermore, a working prototype is implemented using discrete components on a PCB. The measured results show a significant reduction in the average sample frequency and data rate of 50% and 35%, respectively. Finally, the critical analog circuit blocks of the system suitable for integration on chip are proposed and implemented in a 0.35£gm CMOS process. Measured results are reported to confirm the functionality of the blocks.

Constant False Alarm Rate (CFAR) Processors are important for applications where thousands of detection tests are made per second, such as in radar. This thesis introduces a new method for CFAR threshold estimation that is particularly applicable to sound source detection with distributed microphone systems. The novel CFAR Processor exploits the near symmetry about 0 for the acoustic pixel values created by steered-response coherent power in conjunction with a partial whitening preprocessor to estimate thresholds for positive values, which represent potential targets. To remove the low frequency components responsible for degrading CFAR performance, fixed and adaptive high-pass filters are applied. A relation is proposed and it tested the minimum high-pass cut-off frequency and the microphone geometry. Experimental results for linear, perimeter and planar arrays illustrate that for desired false alarm (FA) probabilities ranging from 10-1 and 10-6, a good CFAR performance can be achieved by modeling the coherent power with Chi-square and Weibull distributions and the ratio of desired over experimental FA probabilities can be limited within an order of magnitude.

The safety concern of aging aircraft is a rising issue in terms of both safety and cost. An aircraft structure failure during flight is unacceptable. A method needs to be developed and standardized to test the integrity of both commercial and military aircrafts. The current method to test the structure of an aircraft requires the aircraft to be taken out of service for inspection; this is costly due to the inspection required to be performed and the lost use from downtime. A novice idea of an on-site structural health monitoring (SHM) system has been proposed to test the integrity of aircraft structure. An on-site system is a system that can be used to perform inspection on an aircraft simultaneously while the aircraft is in use. This SHM system uses the principles of active lamb wave and passive acoustic emission through the use of piezoelectric sensors as the sensing elements. Piezoelectric sensors can be used both as an input device and as a sensing element. This research focuses on the development of the major data acquisition electronic components of the system. These components are charge amplifier, high pass filter, low pass filter and line driver. A charge amplifier converts a high impedance signal to a low impedance signal. A high pass filter attenuates the low frequency content of a signal, while a low pass filter attenuates the high frequency content of a signal. A line driver converts a low current signal to a high current signal. All of these components need to operate up to a frequency of 2 MHz. Off-the-shelf electronics will be used for prototyping as custom components will not be feasible at this point of the research. / Master of Science

In recent years, as the availability of remote sensing imagery of varying resolution has increased, merging images of differing spatial resolution has become a significant operation in the field of digital remote sensing. This practice, known as data fusion, is designed to enhance the spatial resolution of multispectral images by merging a relatively coarse-resolution image with a higher resolution panchromatic image of the same geographic area. This study examines properties of fused images and their ability to preserve the spectral integrity of the original image. It analyzes five current data fusion techniques for three complex scenes to assess their performance. The five data fusion models used include one spatial domain model (High-Pass Filter), two algebraic models (Multiplicative and Brovey Transform), and two spectral domain models (Principal Components Transform and Intensity-Hue-Saturation). SPOT data were chosen for both the panchromatic and multispectral data sets. These data sets were chosen for the high spatial resolution of the panchromatic (10 meters) data, the relatively high spectral resolution of the multispectral data, and the low spatial resolution ratio of two to one (2:1). After the application of the data fusion techniques, each merged image was analyzed statistically, graphically, and for increased photointerpretive potential as compared with the original multispectral images. While all of the data fusion models distorted the original multispectral imagery to an extent, both the Intensity-Hue-Saturation Model and the High-Pass Filter model maintained the original qualities of the multispectral imagery to an acceptable level. The High-Pass Filter model, designed to highlight the high frequency spatial information, provided the most noticeable increase in spatial resolution. / Master of Science

The separation and reattachment of the suction surface boundary layer in a low pressure turbine is characterized using large-eddy simulation at Re=68,000 based on freestream velocity and suction surface length. A high pass filtered Smagorinsky model is used for modeling the sub-grid scales. The onset of time mean separation is at s=so = 0:61 and reattachment at s=so = 0:81, extending over 20% of the suction surface. The boundary layer is convectively unstable with a maximum reverse flow velocity of about 13% of freestream. The breakdown to turbulence occurs over a very short distance of suction surface which is followed by reattachment. Detailed investigations into the structure and kinematics of the bubble and turbulence statistics are presented. The vortex shed from the bubble, convects downstream and interacts with the trailing edge vortices increasing the turbulence intensity. On the suction side, dominant hairpin structures near the transitional and turbulent flow regime are observed. These hairpin vortices are carried by the freestream even downstream of the trailing edge of the blade with a possibility of reaching the next stage. Longitudinal streaks that evolve from the breakdown of hairpin vortices formed near the leading edge are observed on the pressure surface.

本研究所要討論的是如何以局部區域的數值高程模型資料辨識出所在整體地形的相對應位置。數值高程模型是以網格式的方式描述地表上連續性的起伏變化，以二維陣列儲存地表高度的資料，包含三度空間的特性。 我們從區域地形萃取出線性特徵與點特徵，分別為水系河段與地形上較明顯的凸點與凹點，以水系作為識別每一區域地形的“指紋”，對於地形變化小或河段特徵不明顯之區域尋找其特徵點，配合相關地形參數與整體地形進行比對，並對不同之特徵採用不同比對演算法。我們以物件化的方式表達水系河段與特徵點，將許多圖層的資訊整合於物件中，除了方便資料的管理，也加快了比對的效率。實驗結果顯示，應用此兩種特徵值作為辨識地形依據，可有效辨識出正確位置，也節省許多不必要的比對時間。 / The main objective of this thesis is to identify a terrain using partial Digital Elevation Model (DEM) information. DEM is one of the most commonly used data representation models used in Geographical Information Systems. It is a digital model with an array of uniformly spaced elevation data in raster format. One can use DEM to analyze terrain measures including slope, aspect, and other features. In the thesis, we use hydrology analysis to extract the stream networks and use terrain parameter analysis to compute terrain features from the DEM of a small region. This information can be used as the “fingerprints” of the terrain and then compare them with the “fingerprints” in the whole data base in order to identify or to locate the correct location of the region. The KMP string matching algorithm is used to speed up the matching process. Measurements extracted from DEM through hydrology analysis may not provide significant terrain information for the identification purpose. In this case, other mechanism such as VIP node and algorithm are used to facilitate the identification process. We embed object oriented concepts in actual implementation. The experimental results show that our mechanism works successfully and the time used in the identification process reduced significantly.

Made available in DSpace on 2015-05-08T14:59:31Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2538187 bytes, checksum: 1a5b7534475b55c4c0d10bb2bc04a315 (MD5) Previous issue date: 2011-05-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The purpose of this work is to develop a strategy for determining the electromagnetic torque of induction motors (MIT) from the stator flux estimation, which presents higher robustness against parametric variations. The stator flux is estimated by integrating the voltage model of the machine, applying Highpass Filters (HFP) for ideal integration of electromotive force against, leading to compensation of offsets in the measurements of voltage, current and its integral, so enable practical implementations of control strategies, failure prediction and energy efficiency. Simulated and experimental results are presented to validate the proposed strategy, evaluating the efficiency of the estimation of transient load and a wide range of machine operation / A proposta deste trabalho é o desenvolvimento de uma estratégia para determinação do conjugado eletromagnético de Motores de Indução Trifásicos (MIT) a partir da estimação do fluxo estatórico, que apresenta maior robustez frente a variações paramétricas. O fluxo estatórico é estimado integrando-se o modelo de tensão da máquina, aplicando-se Filtros Passa Altas (FPA) para integração ideal da força contra eletromotriz, ocasionando a compensação dos offsets nas medições de tensão, corrente e suas integrais, de forma a permitir implementações práticas das estratégias de controle, predição de falhas e eficiência energética. Resultados simulados e experimentais são apresentados para validação da estratégia proposta, avaliando-se a eficiência da estimação em transitórios de carga e em uma ampla faixa de operação da máquina.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work shows and compares three different flux estimator algorithms developed for use in high-performance sensorless ac motor drives. The first algorithm uses a low pass filter with a very low cut off frequency to integrate the back electromotive force (emf). The second one uses a high pass filter to remove the offset present in the signal before it s integration. The third algorithm uses current and voltage model to estimate the flux of induction motor. These algorithms can be used to accurately measure the motor flux including magnitude and phase angle over a wide speed range. The performance of the algorithms is investigated, compared, and verified using simulation and experimental tests. / Este trabalho tem como objetivo apresentar uma comparação entre três algoritmos estimadores de fluxo estatórico diferentes. Estes algoritmos foram desenvolvidos para serem usados no projeto de acionamentos de alto desempenho, sem sensor de velocidade, para motores de indução. O primeiro algoritmo adotado utiliza um filtro passa baixa com uma freqüência de corte baixa para resolver a integração. O segundo algoritmo usa um filtro passa alta para retirar o offset do sinal de entrada do integrador puro. O terceiro algoritmo é um algoritmo híbrido que utiliza os modelos de tensão e corrente em paralelo para estimar o fluxo. Os algoritmos estimam fluxo estatórico em uma ampla faixa de freqüência de funcionamento do motor de indução e foram implementados na forma de simulação e experimentalmente para comparar o funcionamento dos mesmos em diferentes velocidades de operação do motor. / Mestre em Ciências

Series compensation is extensively applied to the transmission lines to increase the power transfer capability of transmission lines, reduce transmission losses, improve voltage profiles, and improve power oscillation damping and transient stability of power systems. But it modifies the apparent impedance of the transmission lines during fault conditions and might cause the distance protection of transmission lines to encounter directional discrimination issues and reach problems. The non-linear characteristic of metal oxide varistor in series compensation model creates further complexity to the fault analysis and might affects the performance of conventional distance protection scheme. The distance protection issues in the series compensated lines need to be addressed for the reliable and sustainable operation of power system.The directional discrimination issues related to current inversion and voltage inversion phenomenon, and reach problems related to sub-synchronous oscillation phenomenon are addressed in this thesis report. This report aims to analyse the impacts of series compensation on the performance of conventional distance relays, and proposes a new protection solution to mitigate the shortcomings of distance relays in the series compensated lines. The proposed new protection solution includes: new tripping characteristic of quadrilateral distance relays to cope with the steady-state reach problems due to current or voltage inversion, and a new high-pass filtering technique to handle the transient reach problems due to SSO.The proposed new protection algorithm is developed in MATLAB. The performance of new protection algorithm is evaluated by simulating a 500 kV two-source power system with a 200 km series compensated line in EMTDC/ PSCAD (Manitoba Hydro). The proposed new protection solution is found to be beneficial. / Seriekompensation tillämpas i stor utsträckning på överföringsledningarna för att öka överföringsförmågan hos överföringsledningar, minska överföringsförluster, förbättra spänningsprofiler och förbättra effektdämpning och övergående stabilitet hos elsystem. Men det ändrar transmissionslinjernas uppenbara impedans under felförhållanden och kan orsaka att distansskydd för överföringsledningarna stöter på diskrimineringsproblem och uppnår problem. Den icke-linjära egenskapen hos metalloxidvaristor i seriekompensationsmodell skapar ytterligare komplexitet för felanalysen och kan påverka prestandan hos konventionella distansskyddssystem. Distansskydd problemen i seriekompenserade linjer måste lösas för en pålitlig och hållbar drift av elsystemet. De riktningsdiskrimineringsproblem som är relaterade till det aktuella inversions- och spänningsinversionsfenomenet och uppnår problem relaterade till subsynkron oscillationsfenomen tas upp i denna avhandlingsrapport. Denna rapport syftar till att analysera effekterna av seriekompensation för prestanda hos konventionella distansreläer och föreslår en ny skyddslösning för att mildra bristerna i distansreläerna i seriekompenserade linjer. Den föreslagna nya skyddslösningen innefattar: Ny utlösningskaraktäristik för fyrsidig distansreläer för att klara avståndet med stillastående / räckvidden på grund av ström- eller spänningsinversion och en ny högpassfiltreringsteknik för hantering av övergående över- Nå problem på grund av SSO. Den föreslagna nya skyddsalgoritmen har utvecklats i MATLAB. Utförandet av den nya skyddsalgoritmen utvärderas genom simulering av ett 500 kV två-källa kraftverk med en 200 km serie kompenserad linje i EMTDC / PSCAD (Manitoba Hydro). Den föreslagna nya skyddslösningen har visat sig vara fördelaktig.

Disertační práce se zabývá syntézou a analýzou nových obvodových struktur neceločíselného (fraktálního) řádu s řiditelnými parametry. Hlavní cíl této práce je návrh nových řešení filtračních struktur fraktálního řádu v proudovém módu, emulátorů prvků fraktálního řádu a také oscilátorů. Práce obsahuje návrh tří emulátorů pasivního prvku fraktálního řádu, tři filtrační struktury a dva oscilátory navržené na základě využití pasivního prvku fraktálního řádu v jejich obvodové struktuře a dvě obecné koncepce filtrů fraktálního řádu založené na využití aproximace přenosové funkce fraktálního řádu. Na základě obecných koncepcí jsou v práci navrženy filtry fraktálního řádu typu dolní a horní propust. Díky aktivním prvkům s přeladitelnými parametry, které jsou užity v obvodových strukturách je zajištěna řiditelnost řádu filtru, jeho pólového kmitočtu a některých případech i činitele jakosti. Vlastnosti všech zapojení jsou ověřeny počítačovými simulacemi za pomoci behavioralních simulačních modelů aktivních prvků. Některé z uvedených obvodů byly realizovány na DPS a jejich vlastnosti ověřeny experimentálním měřením.