This thesis proposes to estimate the speed of a moving acoustic source by either linear or non linear processing of the resulting Doppler shift present in a high-frequency pilot tone. The source is an acoustic modem (Hermes) which currently uses moving average to estimate and compensate for Doppler shift. A new auto regressive approach to Doppler estimation (labeled IIR method in the text) promises to give a better estimate. The results for a simulated peak velocity of 2 m/s in the presence of additive noise showed an RMSE of 0.23 m/s using moving average vs. 0.00018 m/s for the auto regressive approach. The SNR was 75 dB. The next objective was to compare the estimated Doppler velocity obtained using the two algorithms with the experimental values recorded in real time. The setup consisted of a receiver hydrophone attached to a towing carriage that moved with a known velocity with respect to a stationary acoustic source. The source transmitted 375 kHz pilot tone. The received pilot tone data were preprocessed using the two algorithms to estimate both Doppler shift and Doppler velocity. The accuracy of the algorithms was compared against the true velocity values of the carriage. The RMSE for a message from experiments conducted indoor for constant velocity of 0.4 m/s was 0.6055 m/s using moving average, 0.0780 m/s using auto regressive approach. The SNIR was 6.3 dB. / by Poorani Kathiroli. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

A maior parte do sinal propagante para oeste nos oceanos é explicada pelas ondas de Rossby baroclínicas. Porém, vórtices de mesoescala podem interferir na identificação dessas ondas. A maior adversidade em se distinguir o sinal dessas feições é que os vórtices parecem propagar-se com uma velocidade aproximada à velocidade de fase das ondas. Um dos objetivos do presente trabalho é caracterizar os sinais propagantes para oeste em termos da sua velocidade de fase no Atlântico. A análise se baseia em de dados das anomalias da altura da superfície do mar (ASM) e da temperatura de superfície do mar (TSM) derivados dos altímetros TOPEX/Poseidon e Jason-1 e radiômetro TRMM/TMI. As anomalias de ASM e TSM foram filtradas por um conjunto de filtros de resposta impulsiva finita (FIR) para eliminar o sinais sazonais, interanuais e sinais de alta frequência. A análise de correlação cruzada entre as matrizes zonais-temporais de ASM e TSM foi feita para limitar as conclusões aos sinais presentes simultaneamente em ambas as bases de dados. A velocidade de fase das ondas de Rossby foi estimada via transformada de Radon aplicada às matrizes de correlação cruzada. Um máximo local solitário sobre a origem foi observado nos diagramas de correlação e associado à presença de vórtices de mesoescala. Porém este máximo se alonga com a mesma inclinação correspondente à velocidade de fase das ondas de Rossby. Isto sugere que estes vórtices podem propagar-se sobrepostos às ondas. As velocidades de propagação dos vórtices são estimadas através do ajuste de uma função de decaimento exponencial no tempo e na distância zonal. Análises preliminares da transformada de Fourier mostraram que os sinais propagantes para oeste são predominantemente anuais, embora picos de frequências semi-anuais são observadas nestes espectros. Em decorrência da evidência de que os sinais propagantes para oeste são compostos simultaneamente por vórtices e ondas de Rossby, um filtro baseado na transformada de Radon e sua inversa foi desenvolvido para separar o sinal de feições com simetria circular. O filtro de vórtice circular foi aplicado em três áreas onde se localizam a Corrente das Agulhas, Confluências Brasil-Malvinas e Corrente do Golfo. Com base na análise visual pode-se afirmar que o filtro identificou com sucesso vórtices circulares nas três áreas estudadas, tanto nos dados de ASM como nos de TSM. As velocidades de fase das ondas de Rossby foram ligeiramente mais rápidas, em média, que as velocidades dos vórtices em todas as três áreas, cerca de 10% na ASM e 13% na TSM. As velocidades calculadas após a aplicação do filtro de vórtice circular apresentaram um viés positivo em relação as obtidas via correlações cruzadas. A maior diferença na estimativa das velocidades dos vórtices foi de 21% e nas ondas 25%, ambas na região da Corrente das Agulhas. Baseado nas evidências apresentadas é possível afirmar que vórtices podem se propagar com velocidades semelhantes à velocidade das ondas de Rossby do primeiro modo baroclínico. O lag das correlações cruzadas indicaram que o processo físico que relaciona a variabilidade nos dados de ASM à dos TSM é a advecção causada pela passagem de uma onda planet´aria do primeiro modo baroclínico. Esta advecção pode ser horizontal ou vertical dependendo do processo dominante que ocorre numa dada região. / In the oceans, most of the westward propagating signal is explained by baroclinic Rossby waves. However, mesoscale vortices can interfere in the identification of these waves. The main observational issue is to distinguish eddies from the wave-like propagating signals, since the former propagates with a speed that approximately matches the phase speed of baroclinic Rossby waves. The objective of the present study is to characterize the westward propagating signals in terms of their propagation speeds in the Atlantic. The analysis is based on satellite derived sea surface height (SSH) and sea surface temperature (SST) anomalies from the TOPEX/Poseidon and Jason-1 altimeters and TRMM/TMI radiometer records. The SSH and SST anomaly maps were filtered with a set of finite impulse response filters to eliminate the seasonal and interannual cycles and high frequency signals. The cross-correlation analysis between SSH and SST longitude-time matrices was performed to limit the conclusions to the features that appear simultaneously in both datasets. The of Rossby wave phase speed was estimated via Radon transform applied to the longitude-time cross-correlation matrices. A single local maximum was was observed at the origin of the cross-correlation diagrams and associated to mesoscale vortices. However, this maximum spreads along the same slope that characterizes the the westward Rossby wave phase speed. This suggests that vortices propagate superimposed to Rossby waves. The propagating speed of the vortices is estimated from the linear fit of an exponential decay function. A preliminary Fourier analysis show that the westward propagating signals are predominantly annual, yet peaks in the semiannual frequencies are observed. The evidence that the westward propagating signals are composed simultaneously of vortices and Rossby waves motivated the development of a filter based in the Radon transform and its inverse, to isolate the signal associated to circularly symmetric features. This circular vortex filter was applied in three areas that portray the Agulhas Current, the Brazil-Malvinas Confluence, and the Gulf Stream. Based on visual analysis one can affirm that the circular filter sucessfully identified vortices in three areas, both in the SSH and in the SST data. The phase speeds of Rossby waves were, on average, slightly faster than vortices speeds in the three areas, approximately 10% in SSH and 13% in SST. The speeds calculated after the circular vortex filter was applied presented a positive bias in relation to those obtain from cross correlations. The largest difference in the vortices speeds was 21% and in the wave speeds 25%, both in Agulhas Current region. Based on the present evidences it is possible to state that vortices can propagate with speeds similar to those of first-mode baroclinic Rossby waves. The cross-correlation lag suggests that the physical process that links the variability of the SSH to that of the SST is the advection generated by the passage of a first-mode baroclinic planetary wave. This advection can be horizontal or vertical depending of the dominant process in a given region.

Made available in DSpace on 2016-03-22T17:26:08Z (GMT). No. of bitstreams: 1 leandro zafalon.pdf: 1268402 bytes, checksum: cd35030285126fa95b61d98c6a518798 (MD5) Previous issue date: 2008-08-08 / The main goal of this work is the implementation and analyzes of new array multiplier architectures. These new architectures were recently presented in the scientific community by including different power reduction techniques, such as the use of efficient adder circuits and the optimization of the dedicated multiplication structures that allow the multiplication operation in the radix 2m. The new multipliers operate in 2´s complement and keep the same regularity presented by a conventional array multiplier. The architectures operate in the radix 2m, where m represents the group of bits multiplied at a time. In a conventional array multiplier, where the multiplication is performed bit by bit, m assumes value equal 1 (radix 2 operation). In this work, the new multiplier architectures operate in different radices, leading to a reduction in the number of partial product lines, enabling higher performance and power reduction in the multipliers. The 16, 32 and 64 bit width multipliers were described in textual language (gate level), and the comparisons between the multipliers are preformed in terms of area, delay and power consumption by using SIS environment (for area and delay results) and SLS tool (for power consumption estimation). In this work we have applied the proposed optimized multipliers in digital filtering algorithms such as finite impulse response (FIR) and dedicated architecture for the LMS (Least Mean Square) adaptive filtering / O objetivo principal deste trabalho é a implementação e análise de novas arquiteturas de circuitos multiplicadores array digitais recentemente apresentados no meio cientifico com diferentes técnicas de redução de potência, tais como a utilização de eficientes estruturas de circuitos somadores, bem como a otimização dos blocos dedicados de multiplicação, que permitem a operação de multiplicação na base 2m. A proposta de novas arquiteturas consiste em operações de multiplicação em complemento de 2 e que mantenham a mesma regularidade de um multiplicador array convencional. As arquiteturas podem operar com números na base 2m, onde m representa o grupo de bits de multiplicação. Em um multiplicador array convencional, onde a operação de multiplicação é realizada bit a bit, o valor de m é igual a 1 (operação na base 2). Neste trabalho, são apresentadas novas arquiteturas de multiplicadores que operam em diferentes bases, o que permite a redução do número de linhas de produtos parciais, com impactos diretos no aumento de desempenho e redução do consumo de potência. A implementação dos diferentes circuitos multiplicadores foi realizada no nível textual (nível de portas lógicas), onde circuitos multiplicadores de 16, 32 e 64 bits são comparados em termos de parâmetros de área, atraso e consumo de potência utilizando os ambientes SIS (para valores de área e atraso) e SLS (para estimação de valores de consumo de potência). Como estudos de caso, as diferentes arquiteturas de circuitos multiplicadores propostas neste trabalho foram aplicadas em filtros digitais de resposta finita ao impulso (FIR) e em arquitetura dedicada de algoritmo de filtragem adaptativa LMS (Least Mean Square)

Ondas de Rossby longas são ondas de larga escala que se propagam para o oeste com escala espacial de algumas centenas a vários milhares de quilômetros e desempenham um papel crítico na regulação da circulação do oceano. Sua propagação promove deslocamentos verticais da termoclina, muitas vezes da ordem de dezenas de metros, e causa variações de altura da superfície do mar que podem ser observadas através de dados de satélites altimétricos. A hipótese deste estudo é que existe uma fração significativa da variabilidade da velocidade geostrófica na superfície, associada a sinais propagantes para oeste. Para testá-la avaliamos a variabilidade da velocidade geostrófica meridional na superfície induzida pela passagem dessas ondas. Filtros digitais são necessários para distinguir sinais propagantes dos não-propagantes e permitiu a seleção da componente propagante para oeste com período aproximado de 12 meses. Velocidade de fase cp, período P, comprimento de onda λ, amplitude quadrática média A e o percentual de variância explicada σ2 desta componente foram estimados nos locais onde identificamos ondas de Rossby longas do primeiro modo baroclínico. Selecionamos perfis Argo posicionados em diferentes fases da mesma onda para averiguar a influência da sua propagação nos campos de temperatura, salinidade e densidade. Os resultados revelaram que a onda de Rossby anual de 237 mm de altura pode alterar o campo de densidade com valores de até 0,3 kg m-3 numa faixa de 240 m ao nível picnoclina. A variância explicada da componente meridional da velocidade geostrófica propagante para oeste em relação ao sinal original revelou que de 40% a 71% do sinal se propaga para oeste, corroborando a hipótese. / Long Rossby waves are large-scale waves which propagate westward with spatial scale ranging from a few hundred to several thousand kilometers. These waves play a critical role in the adjustment of ocean circulation. Their propagation cause vertical displacements of the thermocline, often of tens meters, and cause variations of sea surface height that can be observed on satellite altimeters data. The hypothesis of this study is that there is a significant fraction of surface geostrophic velocity variability associated with westward propagating signals. To test it, we assessed the variability of the meridional geostrophic velocity at the surface induced by the passage of these waves. Digital filters are necessary to distinguish the propagating from non-propagating signals and allowed for the selection of the westward propagating component with an approximate period of about 12 months. Phase speed cp, period P, wavelength λ, mean square amplitude A and percentage of explained variance σ2 of this component were estimated where long Rossby waves from the first baroclinic mode were identified. We selected Argo profiles data positioned at different phases of the same wave to verify the influence of its propagation on temperature, salinity and density fields. The results showed that the annual Rossby wave of 237 mm height can change the density field with values up to 0.3 kg m-3 about 240 m at pycnoclin level. The explained variance of the westward meridional component of geostrophic velocity relative to the original signal revealed that 40% to 71% of the signal propagates westward, supporting the hypothesis.

by Lai Wai Kuen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves [119-125]). / Abstract --- p.i / Acknowledgement --- p.ii / Table of Contents --- p.iii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Background - The Need for Nonlinear Filtering --- p.1.1 / Chapter 1.2 --- Nonlinear Filtering --- p.1.2 / Chapter 1.3 --- Goal of the Work --- p.1.4 / Chapter 1.4 --- Organization of the Thesis --- p.1.5 / Chapter Chapter 2 --- An Overview of Robust Estimator Based Filters Morphological Filters / Chapter 2.1 --- Introduction --- p.2.1 / Chapter 2.2 --- Signal Representation by Sets --- p.2.2 / Chapter 2.3 --- Robust Estimator Based Filters --- p.2.4 / Chapter 2.3.1 --- Filters based on the L-estimators --- p.2.4 / Chapter 2.3.1.1 --- The Median Filter and its Derivations --- p.2.5 / Chapter 2.3.1.2 --- Rank Order Filters and Derivations --- p.2.9 / Chapter 2.3.2 --- Filters based on the M-estimators (M-Filters) --- p.2.11 / Chapter 2.3.3 --- Filter based on the R-estimators --- p.2.13 / Chapter 2.4 --- Filters based on Mathematical Morphology --- p.2.14 / Chapter 2.4.1 --- Basic Morphological Operators --- p.2.14 / Chapter 2.4.2 --- Morphological Filters --- p.2.18 / Chapter 2.5 --- Chapter Summary --- p.2.20 / Chapter Chapter 3 --- Multi-Structuring Element Erosion Filter / Chapter 3.1 --- Introduction --- p.3.1 / Chapter 3.2 --- Problem Formulation --- p.3.1 / Chapter 3.3 --- Description of Multi-Structuring Element Erosion Filter --- p.3.3 / Chapter 3.3.1 --- Definition of Structuring Element for Multi-Structuring Element Erosion Filter --- p.3.4 / Chapter 3.3.2 --- Binary multi-Structuring Element Erosion Filter --- p.3.9 / Chapter 3.3.3 --- Selective Threshold Decomposition --- p.3.10 / Chapter 3.3.4 --- Multilevel Multi-Structuring Element Erosion Filter --- p.3.15 / Chapter 3.3.5 --- A Combination of Multilevel Multi-Structuring Element Erosion Filter and its Dual --- p.3.21 / Chapter 3.4 --- Chapter Summary --- p.3.21 / Chapter Chapter 4 --- Properties of Multi-Structuring Element Erosion Filter / Chapter 4.1 --- Introduction --- p.4.1 / Chapter 4.2 --- Deterministic Properties --- p.4.2 / Chapter 4.2.1 --- Shape of Invariant Signal --- p.4.3 / Chapter 4.2.1.1 --- Binary Multi-Structuring Element Erosion Filter --- p.4.5 / Chapter 4.2.1.2 --- Multilevel Multi-Structuring Element Erosion Filter --- p.4.16 / Chapter 4.2.2 --- Rate of Convergence of Multi-Structuring Element Erosion Filter --- p.4.25 / Chapter 4.2.2.1 --- Convergent Rate of Binary Multi-Structuring Element Erosion Filter --- p.4.25 / Chapter 4.2.2.2 --- Convergent Rate of Multilevel Multi-Structuring Element Erosion Filter --- p.4.28 / Chapter 4.3 --- Statistical Properties --- p.4.30 / Chapter 4.3.1 --- Output Distribution of Multi-Structuring Element Erosion Filter --- p.4.30 / Chapter 4.3.1.1 --- One-Dimensional Statistical Analysis of Multilevel Multi-Structuring Element Erosion Filter --- p.4.31 / Chapter 4.3.1.2 --- Two-Dimensional Statistical Analysis of Multilevel Multi-Structuring Element Erosion Filter --- p.4.32 / Chapter 4.3.2 --- Discussions on Statistical Properties --- p.4.36 / Chapter 4.4 --- Chapter Summary --- p.4.40 / Chapter Chapter 5 --- Performance Evaluation / Chapter 5.1 --- Introduction --- p.5.1 / Chapter 5.2 --- Performance Criteria --- p.5.2 / Chapter 5.2.1 --- Noise Suppression --- p.5.5 / Chapter 5.2.2 --- Subjective Criterion --- p.5.16 / Chapter 5.2.3 --- Computational Requirement --- p.5.20 / Chapter 5.3 --- Chapter Summary --- p.5.23 / Chapter Chapter 6 --- Recapitulation and Suggestions for Further Work / Chapter 6.1 --- Recapitulation --- p.6.1 / Chapter 6.2 --- Suggestions for Further Work --- p.6.4 / Chapter 6.2.1 --- Probability Measure Function for the Two-Dimensional Filter --- p.6.4 / Chapter 6.2.2 --- Hardware Implementation --- p.6.5 / References / Appendices

Ondas de Rossby longas são ondas de larga escala que se propagam para o oeste com escala espacial de algumas centenas a vários milhares de quilômetros e desempenham um papel crítico na regulação da circulação do oceano. Sua propagação promove deslocamentos verticais da termoclina, muitas vezes da ordem de dezenas de metros, e causa variações de altura da superfície do mar que podem ser observadas através de dados de satélites altimétricos. A hipótese deste estudo é que existe uma fração significativa da variabilidade da velocidade geostrófica na superfície, associada a sinais propagantes para oeste. Para testá-la avaliamos a variabilidade da velocidade geostrófica meridional na superfície induzida pela passagem dessas ondas. Filtros digitais são necessários para distinguir sinais propagantes dos não-propagantes e permitiu a seleção da componente propagante para oeste com período aproximado de 12 meses. Velocidade de fase cp, período P, comprimento de onda λ, amplitude quadrática média A e o percentual de variância explicada σ2 desta componente foram estimados nos locais onde identificamos ondas de Rossby longas do primeiro modo baroclínico. Selecionamos perfis Argo posicionados em diferentes fases da mesma onda para averiguar a influência da sua propagação nos campos de temperatura, salinidade e densidade. Os resultados revelaram que a onda de Rossby anual de 237 mm de altura pode alterar o campo de densidade com valores de até 0,3 kg m-3 numa faixa de 240 m ao nível picnoclina. A variância explicada da componente meridional da velocidade geostrófica propagante para oeste em relação ao sinal original revelou que de 40% a 71% do sinal se propaga para oeste, corroborando a hipótese. / Long Rossby waves are large-scale waves which propagate westward with spatial scale ranging from a few hundred to several thousand kilometers. These waves play a critical role in the adjustment of ocean circulation. Their propagation cause vertical displacements of the thermocline, often of tens meters, and cause variations of sea surface height that can be observed on satellite altimeters data. The hypothesis of this study is that there is a significant fraction of surface geostrophic velocity variability associated with westward propagating signals. To test it, we assessed the variability of the meridional geostrophic velocity at the surface induced by the passage of these waves. Digital filters are necessary to distinguish the propagating from non-propagating signals and allowed for the selection of the westward propagating component with an approximate period of about 12 months. Phase speed cp, period P, wavelength λ, mean square amplitude A and percentage of explained variance σ2 of this component were estimated where long Rossby waves from the first baroclinic mode were identified. We selected Argo profiles data positioned at different phases of the same wave to verify the influence of its propagation on temperature, salinity and density fields. The results showed that the annual Rossby wave of 237 mm height can change the density field with values up to 0.3 kg m-3 about 240 m at pycnoclin level. The explained variance of the westward meridional component of geostrophic velocity relative to the original signal revealed that 40% to 71% of the signal propagates westward, supporting the hypothesis.

Thesis. 1978. Elec.E.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / Elec.E.

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Paul Moroney. / Ph.D.

Thesis. 1978. Sc.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Vita. / Bibliography: p. 142-145. / Sc.D.