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Distribui??o espacial, biologia populacional das esp?cies de braqui?ros e crescimento som?tico de Uca rapax (Smith, 1870) no manguezal de Jabaquara/ Paraty - RJ / Spatial distribution, population biology of the brachyuran crabs (Crustacea, Decapoda) and somatic growth of Uca rapax (Smith, 1870) (Crustacea, Decapoda, Ocypodidae) in the Jabaquara`s mangrove/Paraty - RJBED?, Luciane Marins 30 June 2011 (has links)
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Previous issue date: 2011-06-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / This study was conducted in the Jabaquara mangrove, Paraty, Rio de Janeiro, with the aim of
investigate the spatial distribution, population biology of brachyuran species and somatic
growth of Uca rapax (Smith, 1870) (Crustacea, Decapoda, Ocypodidae) in the Jabaquara`s
mangrove/Paraty - RJ. Sampling was performed in two grids from July 2007 to June 2008,
using the capture effort per unit. Two collectors captured the crab monthly, during 15 minutes
in low tide. Sediment samples from all the selected plots were collected to determinate
particle size and organic matter. Air temperature and salinity also were measured. Eight
species of brachyuran were captured, U. rapax, U. thayeri, U. vocator, U. uruguayensis, U.
cumulanta, Neohelice granulata, Ucides cordatus and Eurytium limosum. U. rapax was the
most abundant species in number of individuals and ovigerous females. The results indicated
that distribution of the species was influenced by abiotic factors. The most species were more
abundant in the inner portions of the mangroove and near of the sea. The ovigerous females of
U. rapax were more abundant in the inner portions of the mangroove and near from the sea
and N. granulata more distant from the sea. U. rapax showed a positive correlation with
organic matter. U. thayeri, U. uruguayensis and E. limosum negatively correlated to distance
from the sea. U. vocator showed positive correlation for sand and organic matter and
negatively correlated to distance from the sea. U. cumulanta was positively correlated to sand.
The ovigerous females of U. rapax showed a positive correlation to air temperature and
organic matter. N. granulata and U. cordatus were the species more versatile in habitat
colonization. The size of the crabs in the Jabaquara?s Mangrove were the smallest size than
those found in other Brazilian mangroves. However, the males attained a larger size than
females. The size frequency distribution was unimodal for the most species. In general, the
males were predominant in all size classes, and more evident in larger classes. The sex ratio
differ significant from 1:1 proportion (male: female), which most of the time dislocated for
males. The most species showed a seasonal reproductive period, with more abundance of
ovigerous females during the spring and summer. The growth curves in width (mm) for males
and females were described by the equations: LC= 24,28 [ 1- e -0,0038(t-2,8) ] and LC= 22,0 [ 1-
e -0,0031(t-2,3)], respectively. The males reach larger sizes and a higher growth rate than females.
The longevity was estimated at three years for males and four years for females / Este trabalho foi realizado no manguezal de Jabaquara, em Paraty, Rio de Janeiro com o
objetivo de analisar a distribui??o espacial, a biologia populacional das esp?cies de braqui?ros
e o crescimento som?tico de Uca rapax (Smith, 1870) no manguezal de Jabaquara/ Paraty ?
RJ. As coletas foram realizadas em dois grides de julho 2007 a junho2008, utilizando-se a
t?cnica de esfor?o por unidade de captura. Dois coletores capturaram os caranguejos
mensalmente, durante 15 minutos em per?odo de mar? baixa. Amostras de sedimento foram
coletadas nas parcelas selecionadas, para determinar o tamanho das part?culas e mat?ria
org?nica e a temperatura do ar e a salinidade tamb?m foram tomados. Foram capturadas oito
esp?cies de braqui?ros: U. rapax, U. thayeri, U. vocator, U. uruguayensis, U. cumulanta,
Neohelice granulata, Ucides cordatus e Eurytium limosum. U. rapax foi ? esp?cie mais
abundante em n?mero de indiv?duos e de f?meas ov?geras. Os resultados revelaram que a
distribui??o das esp?cies foi influenciada pelos fatores abi?ticos. A maioria das esp?cies foi
mais abundante nas parcelas mais internas do manguezal e pr?ximas ao mar. As f?meas
ov?geras de U. rapax e N. granulata foram mais abundantes nas parcelas mais internas do
manguezal e mais pr?ximas e mais distantes do mar, respectivamente. U. rapax apresentou
correla??o positiva para mat?ria org?nica. U. thayeri, U. uruguayensis e E. limosum
apresentaram correla??o negativa para dist?ncia do mar. U. vocator apresentou correla??o
positiva para areia e mat?ria org?nica e correla??o negativa para dist?ncia do mar. U.
cumulanta apresentou correla??o positiva para areia. As f?meas ov?geras de U. rapax
apresentaram uma correla??o positiva para temperatura do ar e mat?ria org?nica. N. granulata
e U. cordatus foram as esp?cies mais vers?teis em formas de colonizar ambientes. Com
rela??o ao tamanho dos indiv?duos, observou-se que os braqui?ros do Manguezal de
Jabaquara, de maneira geral, apresentam tamanhos maiores que os encontrados em outros
manguezais do Brasil. Contudo, os machos atingiram tamanhos maiores que as f?meas. A
distribui??o de freq??ncia em classes de tamanho foi unimodal para a maioria das esp?cies.
De maneira geral, os machos foram predominantes em todas as classes de tamanho, sendo
mais evidente nas maiores classes. A raz?o sexual diferiu significativamente da propor??o
1:1, estando na maioria das vezes deslocada para os machos. A maioria das esp?cies
apresentou um per?odo reprodutivo sazonal, ocorrendo maior abund?ncia de f?meas ov?geras
na primavera e no ver?o. O modelo de von Bertalanffy foi utilizado para a descri??o do
crescimento. As curvas de crescimento em largura (mm) para machos e f?meas de U. rapax,
foram descritas pelas equa??es: LC= 24,28 [ 1- e -0,0038(t-2,8) ] e LC= 22,0 [ 1- e -0,0031(t-2,3)],
respectivamente. Os machos apresentaram uma taxa de crescimento maior do que as f?meas.
A longevidade foi estimada em 3 anos para os machos e 4 anos para as f?meas.
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Origin of Suppression of Otoacoustic Emissions Evoked by Two-Tone BurstsJedrzejczak, W. Wiktor, Smurzynski, Jacek, Blinowska, KatarzynaJ. 01 January 2008 (has links)
Otoacoustic emission (OAE) data recorded for tone bursts presented separately and as a two-tone burst complex, that had been reported previously [Yoshikawa, H., Smurzynski, J., Probst R., 2000. Suppression of tone burst evoked otoacoustic emissions in relation to frequency separation. Hear. Res. 148, 95–106], were re-processed using the method of adaptive approximations by matching pursuit (MP). Two types of stimuli were applied to record tone burst OAEs (TBOAEs): (a) cosine-windowed tone bursts of 5-ms duration with center frequencies of 1, 1.5, 2 and 3kHz, (b) complex stimuli consisting of a digital addition of the 1-kHz tone burst together with either the 1.5-, 2- or 3-kHz tone burst. The MP method allowed decomposition of signals into waveforms of defined frequency, latency, time span, and amplitude. This approach provided a high time–frequency (t–f) resolution and identified patterns of resonance modes that were characteristic for TBOAEs recorded in each individual ear. Individual responses to single-tone bursts were processed off-line to form ‘sum of singles’ responses. The results confirmed linear superposition behavior for a frequency separation of two-tone bursts of 2kHz (the 1-kHz and 3-kHz condition). For the 1, 1.5-kHz condition, the MP results revealed the existence of closely positioned resonance modes associated with responses recorded individually with the stimuli differing in frequency by 500Hz. Then, the differences between t–f distributions calculated for dual (two-tone bursts) and sum-of-singles conditions exhibited mutual suppression of resonance modes common to both stimuli. The degree of attenuation depended on the individual pattern of characteristic resonance modes, i.e., suppression occurred when two resonant modes excited by both stimuli overlapped. It was postulated that the suppression observed in case of dual stimuli with closely-spaced components is due to mutual attenuation of the overlapping resonance modes.
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Seleção e depressão por endogamia para a cultivar de mamona FCA-PB, em progênies obtidas por diferentes métodos de polinização / Selection and inbreeding depression for the castor bean FCA-PB, in progenies obtained by different pollination methodsSilva, Jackson da 18 July 2018 (has links)
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Previous issue date: 2018-07-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A mamona (Ricinus communis) está presente em inúmeras aplicações na área industrial e na produção de biodiesel, tendo assim, relevante importância econômica. Contudo, no ano de 2017, o Brasil apresentou produtividade de 470 kg ha-1, muito aquém do seu real potencial, devido à falta de genótipos adaptados a cada região produtora. A síntese de híbridos produtivos passa pela obtenção de linhagens puras com o mínimo de endogamia, para maior exploração do vigor de híbrido, que proporcionam plantas mais uniformes e mais produtivas. Assim, o presente trabalho teve por objetivo estimar a depressão por endogamia em progênies obtidas por autofecundação, polinização cruzada e polinização livre advindas do cultivar de mamona FCA-PB. Os experimentos foram implantados em delineamento em blocos casualizados, no esquema fatorial 90 x 2 x 2, sendo 90 progênies advindas de três tipos de polinização, em 2 ambientes (São Manuel e Araçatuba) e em 2 safras (2004/2005 e 2005/2006), e no esquema fatorial 30 x 3, sendo 30 progênies e 3 tipos de polinização, em 2 ambientes e em 2 safras, com três repetições. Com relação à safra 2005/2006, a progênie 49 cultivada no município de São Manuel produziu 4171 kg ha-1 de grãos, podendo o seu desempenho ser explicado pelo tipo de fecundação que foi originada, polinização cruzada, sendo este método o que ocasiona no maior nível de heterose. Na avaliação da depressão por endogamia verificou-se que a polinização cruzada apresentou maior produtividade de grãos e menor coeficiente de endogamia. Por outro lado, a menor produtividade foi observada na autopolinização, a qual obteve maior coeficiente de endogamia. Considerando o potencial produtivo das 20 % melhores progênies, podem ser selecionadas as progênies 1, 5, 6, 8, 15, 18, 19, 21, 27, 31, 35, 36, 38, 45, 49, 55, 56 e 58. Verificou-se também, que o coeficiente de endogamia na produtividade apresenta comportamento inversamente proporcional. / Castor bean (Ricinus communis) is present in numerous applications in the industrial area and in the production of biodiesel, having thus, relevant economic importance. However, in the year 2017, Brazil presented productivity of 470 kg ha-1, far short of its real potential, due to the lack of genotypes adapted to each producing region. The synthesis of productive hybrids passes through the obtaining of pure lineages with the minimum of endogamy, for greater exploitation of hybrid vigor, which provide more uniform and more productive plants. Thus, the present study aimed to estimate depression by inbreeding in progenies obtained by self-fertilization, cross pollination and free pollination from the cultivar of castor bean FCA-PB. The experiments were in a randomized block design, in the factorial scheme 90 x 2 x 2, being 90 progenies coming from three types of pollination, in 2 environments and 2 crops, and in the factorial scheme 30 x 3, being 30 progenies and 3 types of pollination, in 2 environments (São Manuel and Araçatuba) and in 2 crops (2004/2005 and 2005/2006), with three replications. In relation to the 2005/2006 crop, the progeny 49 grown in the municipality of São Manuel produced 4171 kg ha-1 of grains, and its performance can be explained by the type of fertilization that originated, cross pollination, being this method that causes in the greater level of heterosis. In the assessment of inbreeding depression it has been found that cross pollination presented greater productivity of grain and lower coefficient of inbreeding. On the other hand, the lower productivity was observed in self-pollination, which obtained higher coefficient of inbreeding. Considering the productive potential of the 20 % best progenies, can be selected the progenies 1, 5, 6, 8, 15, 18, 19, 21, 27, 31, 35, 36, 38, 45, 49, 55, 56 and 58. It was verified also, that the coefficient of inbreeding in productivity presents inversely proportional behavior. / 830842/1999-3
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Frequency scaling of rain attenuation on satellite links in the Ku/Ka-bands using OLYMPUS satellite dataLaster, Jeff D. 16 June 2009 (has links)
Frequency scaling of attenuation is the prediction of attenuation at a desired frequency from attenuation values at a base frequency. The attenuation at the base frequency is often known from prior measurements. Frequency scaling of attenuation is of interest because of the eventual need to exploit higher frequency bands. Most satellite communications traffic now use C-band (4-8 GHz) and Ku-band (12-18 GHz). The next approved, yet largely unused, frequency allocation for domestic use is in the K-band (18-27 GHz) to Ka-band (27-40 GHz). At these higher frequencies, however, earth-space radio links suffer atmospherically induced impairments as frequency increases. In particular, rain causes severe fading. Consequently, satellite systems in these higher bands are very susceptible to outages due to rain-induced fades. Reliable frequency scaling models are needed in system design to estimate the effect of these rain-induced fades.
Between August 1990 and August 1992, V.P.I. & S.U.'s SATCOM Group performed extensive measurements of slant path attenuation using the 12, 20, and 30 GHz beacon signals (in the Ku/Ka-bands) of the European OLYMPUS experimental satellite. The experimental results are used to evaluate the usefulness of scaling models proposed by other researchers, both for instantaneous and statistical purposes. New models are presented for accurate scaling of attenuation within the Ku/Ka-bands. / Master of Science
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Estimation and separation of linear frequency- modulated signals in wireless communications using time - frequency signal processing.Nguyen, Linh- Trung January 2004 (has links)
Signal processing has been playing a key role in providing solutions to key problems encountered in communications, in general, and in wireless communications, in particular. Time-Frequency Signal Processing (TFSP) provides eective tools for analyzing nonstationary signals where the frequency content of signals varies in time as well as for analyzing linear time-varying systems. This research aimed at exploiting the advantages of TFSP, in dealing with nonstationary signals, into the fundamental issues of signal processing, namely the signal estimation and signal separation. In particular, it has investigated the problems of (i) the Instantaneous Frequency (IF) estimation of Linear Frequency-Modulated (LFM) signals corrupted in complex-valued zero-mean Multiplicative Noise (MN), and (ii) the Underdetermined Blind Source Separation (UBSS) of LFM signals, while focusing onto the fast-growing area of Wireless Communications (WCom). A common problem in the issue of signal estimation is the estimation of the frequency of Frequency-Modulated signals which are seen in many engineering and real-life applications. Accurate frequency estimation leads to accurate recovery of the true information. In some applications, the random amplitude modulation shows up when the medium is dispersive and/or when the assumption of point target is not valid; the original signal is considered to be corrupted by an MN process thus seriously aecting the recovery of the information-bearing frequency. The IF estimation of nonstationary signals corrupted by complex-valued zero-mean MN was investigated in this research. We have proposed a Second-Order Statistics approach, rather than a Higher-Order Statistics approach, for IF estimation using Time-Frequency Distributions (TFDs). The main assumption was that the autocorrelation function of the MN is real-valued but not necessarily positive (i.e. the spectrum of the MN is symmetric but does not necessary has the highest peak at zero frequency). The estimation performance was analyzed in terms of bias and variance, and compared between four dierent TFDs: Wigner-Ville Distribution, Spectrogram, Choi-Williams Distribution and Modified B Distribution. To further improve the estimation, we proposed to use the Multiple Signal Classification algorithm and showed its better performance. It was shown that the Modified B Distribution performance was the best for Signal-to-Noise Ratio less than 10dB. In the issue of signal separation, a new research direction called Blind Source Separation (BSS) has emerged over the last decade. BSS is a fundamental technique in array signal processing aiming at recovering unobserved signals or sources from observed mixtures exploiting only the assumption of mutual independence between the signals. The term "blind" indicates that neither the structure of the mixtures nor the source signals are known to the receivers. Applications of BSS are seen in, for example, radar and sonar, communications, speech processing, biomedical signal processing. In the case of nonstationary signals, a TF structure forcing approach was introduced by Belouchrani and Amin by defining the Spatial Time- Frequency Distribution (STFD), which combines both TF diversity and spatial diversity. The benefit of STFD in an environment of nonstationary signals is the direct exploitation of the information brought by the nonstationarity of the signals. A drawback of most BSS algorithms is that they fail to separate sources in situations where there are more sources than sensors, referred to as UBSS. The UBSS of nonstationary signals was investigated in this research. We have presented a new approach for blind separation of nonstationary sources using their TFDs. The separation algorithm is based on a vector clustering procedure that estimates the source TFDs by grouping together the TF points corresponding to "closely spaced" spatial directions. Simulations illustrate the performances of the proposed method for the underdetermined blind separation of FM signals. The method developed in this research represents a new research direction for solving the UBSS problem. The successful results obtained in the research development of the above two problems has led to a conclusion that TFSP is useful for WCom. Future research directions were also proposed.
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Evaluation of the wind patterns over the Yucatán Peninsula in MéxicoSoler-Bientz, Rolando January 2010 (has links)
Wind power is seen as one of the most effective means available to combat the twin crises of global climate change and energy security. The annual market growth has established wind power as the leading renewable energy technology. Due to the availability of sparsely populated and flat open terrain, the Yucatán Peninsula located in eastern México is a promising region from the perspective of wind energy development but no comprehensive assessment of wind resource has been previously published. A basic requirement when developing wind power projects is to study the main characteristic parameters of wind in relation to its geographical and temporal distribution. The analysis of diurnal and seasonal wind patterns are an important stage in the move towards commercial exploitation of wind power. The research developed during the PhD has comprehensively assessed the wind behaviour over the Yucatán Peninsula region covering long term patterns at three sites, a spatial study using short term data for nine sites, a vertical profile study on one inland site and an offshore study made on a pier at 6.65km from the North shore. Monthly trends, directional behaviours and frequency distributions were identified and discussed. The characteristics of the wind speed variation reflected their proximity to the coast and whether they were influenced by wind coming predominantly from over the land or predominantly from over the sea. The atmospheric stability over the eastern seas was also analysed to assess thermal effects for different wind directions. Diurnal wind speed variations are shown to be affected in particular by the differing wind conditions associated with fetches over two distinct offshore regions. Seasonal behaviour suggests some departure from the oscillations expected from temperature variation. The offshore wind is thermally driven suggesting largely unstable conditions and the potential development of a shallow Stable Internal Boundary Layer.
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Discrete quadratic time-frequency distributions: Definition, computation, and a newborn electroencephalogram applicationO' Toole, John Unknown Date (has links)
Most signal processing methods were developed for continuous signals. Digital devices, such as the computer, process only discrete signals. This dissertation proposes new techniques to accurately define and efficiently implement an important signal processing method---the time--frequency distribution (TFD)---using discrete signals. The TFD represents a signal in the joint time--frequency domain. Because these distributions are a function of both time and frequency they, unlike traditional signal processing methods, can display frequency content that changes over time. TFDs have been used successfully in many signal processing applications as almost all real-world signals have time-varying frequency content. Although TFDs are well defined for continuous signals, defining and computing a TFD for discrete signals is problematic. This work overcomes these problems by making contributions to the definition, computation, and application of discrete TFDs. The first contribution is a new discrete definition of TFDs. A discrete TFD (DTFD) should be free from the sampling-related distortion known as aliasing and satisfy all the important mathematical properties that the continuous TFD satisfies. Many different DTFD definitions exist but none come close to attaining this ideal. I propose three new components which make up the DTFD: 1) a new discrete Wigner--Ville distribution (DWVD) definition which satisfies all properties, 2) a new discrete analytic signal which minimises aliasing in the DWVD, and 3) a new method to define and convolve the discrete kernel with the DWVD to produce the DTFD. The result: a DTFD definition that, relative to the existing definitions, better approximates the ideal DTFD. The second contribution is two sets of computationally efficient algorithms to compute the proposed DTFD. The first set of algorithms computes the DTFD exactly; the second set requires less memory than the first set by computing time- and, or frequency-decimated versions of the DTFD. Both sets of algorithms reduce the computational load by exploiting symmetries in the DTFD and by constructing kernel-specific algorithms for four different kernel types. The third, and final, contribution is a biomedical application for the proposed DTFD and algorithms. This application is to accurately detect seizure events in newborn electroencephalogram (EEG) signals. Existing detection methods do not perform well enough for use in a clinical setting. I propose a new method which is more robust than existing methods and show how using the proposed DTFD, comparative to an existing DTFD, improves detection performance for this method. In summary, this dissertation makes practical contributions to the area of time--frequency signal processing by proposing an improved DTFD definition, efficient DTFD algorithms, and an improved newborn EEG seizure detection method using DTFDs.
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Radar Range-doppler Imaging Using Joint Time-frequency TechniquesAkhanli, Deniz 01 April 2007 (has links) (PDF)
Inverse Synthetic Aperture Radar coherently processes the return signal from the target in order to construct the image of the target. The conventional methodology used for obtaining the image is the Fourier transform which is not capable of suppressing the Doppler change in the return signal. As a result, Range-Doppler image is degraded. A proper time-frequency transform suppresses the degradation due to time varying Doppler shift.
In this thesis, high resolution joint-time frequency transformations that can be used in place of the conventional method are evaluated. Wigner-Ville Distribution, Adaptive Gabor Representation with Coarse-to-Fine search algorithm, and Time-Frequency Distribution Series are examined for the target imaging system.
The techniques applied to sample signals compared with each other. The computational and memorial complexity of the methods are evaluated and compared to each other and possible improvements are discussed. The application of these techniques in the target imaging system is also performed and resulting images compared to each other.
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Discrete quadratic time-frequency distributions: Definition, computation, and a newborn electroencephalogram applicationO' Toole, John Unknown Date (has links)
Most signal processing methods were developed for continuous signals. Digital devices, such as the computer, process only discrete signals. This dissertation proposes new techniques to accurately define and efficiently implement an important signal processing method---the time--frequency distribution (TFD)---using discrete signals. The TFD represents a signal in the joint time--frequency domain. Because these distributions are a function of both time and frequency they, unlike traditional signal processing methods, can display frequency content that changes over time. TFDs have been used successfully in many signal processing applications as almost all real-world signals have time-varying frequency content. Although TFDs are well defined for continuous signals, defining and computing a TFD for discrete signals is problematic. This work overcomes these problems by making contributions to the definition, computation, and application of discrete TFDs. The first contribution is a new discrete definition of TFDs. A discrete TFD (DTFD) should be free from the sampling-related distortion known as aliasing and satisfy all the important mathematical properties that the continuous TFD satisfies. Many different DTFD definitions exist but none come close to attaining this ideal. I propose three new components which make up the DTFD: 1) a new discrete Wigner--Ville distribution (DWVD) definition which satisfies all properties, 2) a new discrete analytic signal which minimises aliasing in the DWVD, and 3) a new method to define and convolve the discrete kernel with the DWVD to produce the DTFD. The result: a DTFD definition that, relative to the existing definitions, better approximates the ideal DTFD. The second contribution is two sets of computationally efficient algorithms to compute the proposed DTFD. The first set of algorithms computes the DTFD exactly; the second set requires less memory than the first set by computing time- and, or frequency-decimated versions of the DTFD. Both sets of algorithms reduce the computational load by exploiting symmetries in the DTFD and by constructing kernel-specific algorithms for four different kernel types. The third, and final, contribution is a biomedical application for the proposed DTFD and algorithms. This application is to accurately detect seizure events in newborn electroencephalogram (EEG) signals. Existing detection methods do not perform well enough for use in a clinical setting. I propose a new method which is more robust than existing methods and show how using the proposed DTFD, comparative to an existing DTFD, improves detection performance for this method. In summary, this dissertation makes practical contributions to the area of time--frequency signal processing by proposing an improved DTFD definition, efficient DTFD algorithms, and an improved newborn EEG seizure detection method using DTFDs.
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Discrete quadratic time-frequency distributions: Definition, computation, and a newborn electroencephalogram applicationO' Toole, John Unknown Date (has links)
Most signal processing methods were developed for continuous signals. Digital devices, such as the computer, process only discrete signals. This dissertation proposes new techniques to accurately define and efficiently implement an important signal processing method---the time--frequency distribution (TFD)---using discrete signals. The TFD represents a signal in the joint time--frequency domain. Because these distributions are a function of both time and frequency they, unlike traditional signal processing methods, can display frequency content that changes over time. TFDs have been used successfully in many signal processing applications as almost all real-world signals have time-varying frequency content. Although TFDs are well defined for continuous signals, defining and computing a TFD for discrete signals is problematic. This work overcomes these problems by making contributions to the definition, computation, and application of discrete TFDs. The first contribution is a new discrete definition of TFDs. A discrete TFD (DTFD) should be free from the sampling-related distortion known as aliasing and satisfy all the important mathematical properties that the continuous TFD satisfies. Many different DTFD definitions exist but none come close to attaining this ideal. I propose three new components which make up the DTFD: 1) a new discrete Wigner--Ville distribution (DWVD) definition which satisfies all properties, 2) a new discrete analytic signal which minimises aliasing in the DWVD, and 3) a new method to define and convolve the discrete kernel with the DWVD to produce the DTFD. The result: a DTFD definition that, relative to the existing definitions, better approximates the ideal DTFD. The second contribution is two sets of computationally efficient algorithms to compute the proposed DTFD. The first set of algorithms computes the DTFD exactly; the second set requires less memory than the first set by computing time- and, or frequency-decimated versions of the DTFD. Both sets of algorithms reduce the computational load by exploiting symmetries in the DTFD and by constructing kernel-specific algorithms for four different kernel types. The third, and final, contribution is a biomedical application for the proposed DTFD and algorithms. This application is to accurately detect seizure events in newborn electroencephalogram (EEG) signals. Existing detection methods do not perform well enough for use in a clinical setting. I propose a new method which is more robust than existing methods and show how using the proposed DTFD, comparative to an existing DTFD, improves detection performance for this method. In summary, this dissertation makes practical contributions to the area of time--frequency signal processing by proposing an improved DTFD definition, efficient DTFD algorithms, and an improved newborn EEG seizure detection method using DTFDs.
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