139 research outputs found

    Characterization of a metastability measurement system

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    peer-reviewedWe characterize the metastability measurement system [8] in which asynchronous data input and sampling clock frequencies trigger metastability. We develop the equation describing the time interval between data and clock inputs for practical frequencies and show that it takes on discrete values in the absence of jitter and that the presence of jitter perturbs these discrete values. Finally, we present experimental results supporting our characterization.ACCEPTEDpeer-reviewe

    The Cardinality Balanced Multi-Target Multi-Bernoulli Filter and Its Implementations

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    It is shown analytically that the multi-target multi- Bernoulli (MeMBer) recursion, proposed by Mahler, has a significant bias in the number of targets. To reduce the cardinality bias, a novel multi-Bernoulli approximation to the multi-target Bayes recursion is derived. Under the same assumptions as the MeMBer recursion, the proposed recursion is unbiased. In addition, a sequential Monte Carlo (SMC) implementation (for generic models) and a Gaussian mixture (GM) implementation (for linear Gaussian models) are proposed. The latter is also extended to accommodate mildly nonlinear models by linearization and the unscented transform

    Bayesian Filtering With Random Finite Set Observations

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    This paper presents a novel and mathematically rigorous Bayes’ recursion for tracking a target that generates multiple measurements with state dependent sensor field of view and clutter. Our Bayesian formulation is mathematically well-founded due to our use of a consistent likelihood function derived from random finite set theory. It is established that under certain assumptions, the proposed Bayes’ recursion reduces to the cardinalized probability hypothesis density (CPHD) recursion for a single target. A particle implementation of the proposed recursion is given. Under linear Gaussian and constant sensor field of view assumptions, an exact closed-form solution to the proposed recursion is derived, and efficient implementations are given. Extensions of the closed-form recursion to accommodate mild nonlinearities are also given using linearization and unscented transforms

    Variable digital filter with least-square criterion and peak gain constraints

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    FIR variable digital filter with signed power-of-two coefficients

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    Variable digital filters (VDFs) are useful for various signal processing and communication applications where the frequency characteristics, such as fractional delays and cutoff frequencies, can be varied online. In this paper, we investigate the design of VDFs with discrete coefficients as a means of achieving low complexity and efficient hardware implementation. The filter coefficients are expressed as the sum of signed power-of-two terms with a restriction on the total number of power-of-two for the filter coefficients. An efficient design procedure is proposed that includes an improved method for handling the quantization of the VDF coefficients for both the min-max and the least-square criteria leading to an optimum quantized solution. For the least-square criterion, a reduced search region around the optimum quantized solution is further constructed and the branch and bound method in conjunction with an efficient branch cutting scheme is presented to search for an optimum solution in this reduced region

    Blind signal separation using steepest descent method

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    A method that significantly improves the convergence rate of the gradient-based blind signal separation (BSS) algorithm for convolutive mixtures is proposed. The proposed approach is based on the steepest descent algorithm suitable for constrained BSS problems, where the constraints are included to ease the permutation effects associated with the convolutive mixtures. In addition, the method is realized using a modified golden search method plus parabolic interpolation, and this allows the optimum step size to be determined with only a few calculations of the cost function. Evaluation of the proposed procedure in simulated environments and in a real room environment shows that the proposed method results in significantly faster convergence for the BSS when compared with a fixed step-size gradient-based algorithm. In addition, for blind signal extraction where only a main speech source is desired, a combined scheme consisting of the proposed BSS and a postprocessor, such as an adaptive noise canceller, offers impressive noise suppression levels while maintaining low-target signal distortion level

    Frecuencia de secuela renal posevento agudo en síndrome urémico hemolítico

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    Objetivos: Determinar la frecuencia de secuela renal después del evento agudo de Síndrome Urémico Hemolítico (SUH) en niños y los factores asociados a la presencia de secuelas. Material y métodos: Estudio descriptivo y retrospectivo. Se revisaron las historias clínicas de los pacientes con SUH en el HNCH de 1997 al 2012, y se registraron datos de características clínicas, hallazgos de laboratorio y parámetros de función renal al ingreso, al alta y a los seis meses después del alta. En los casos que no contaban con control a los 6 meses, se intentó contactar a los pacientes para tomar nuevos controles. Resultados: Siete de 12 pacientes presentaron disminución en la tasa de filtración glomerular (TFG) o proteinuria o hipertensión a los 6 meses o más después del episodio agudo, con un promedio de 30,75 meses de seguimiento. Tanto en los pacientes con secuelas como con recuperación renal se encontró una distribución similar de los factores asociados a secuelas como hipertensión al alta, proteinuria al alta, necesidad de diálisis, oligoanuria, leucocitosis > 20 000 cel/mm3 y síntomas neurológicos. Sin embargo algunas variables como oligoanuria y necesidad de diálisis se encontraron a niveles por debajo de los descritos en la literatura. Conclusiones: Es claro que existen pacientes con secuelas renales luego del episodio agudo de SUH que además presentan varios factores predictores de secuelas descritos en la literatura

    Frecuencia de secuela renal posevento agudo en síndrome urémico hemolítico

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    Profile of gamma-delta (γδ) T lymphocytes in the peripheral blood of crossbreed dogs during stages of life and implication in aging

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    Abstract Background: Data on gamma-delta (γδ) T lymphocytes in the peripheral blood of dogs are scant, related only to healthy pure breed dogs and limited to a restricted age range. The aim of the study was to investigate the modulation of the γδ T lymphocyte (TCRγδ+) subpopulation in peripheral blood of crossbreed healthy dogs according to five identified stages of life: Puppy, Junior, Adult, Mature, Senior and to determine its implication in aging. A rigorous method of recruitment was used to minimize the influence of internal or external pressure on the immune response. Twenty-three intact female and twenty-four intact male dogs were enrolled. Blood samples were collected and immunophenotyping of peripheral blood T lymphocytes and γδ T cell subpopulations was performed. Results: The percentage of γδ T cells in peripheral blood lymphocytes was comparable with the value of 2.5% published by Faldyna and co-workers (2001), despite the percentage reported was investigated in less arranged age range groups and coming from four different dog pure breeds, whereas our data were recorded on wider age range groups and coming from crossbreed dogs. Therefore, the γδ T cell percentage (2.5%) is consistent and points out that such value is breed-independent. Statistical analysis highlighted differences in both percentage and absolute γδ T cells according to the stage of life. γδ T cells decreased significantly in the peripheral blood of elder dogs (Senior group) in comparison with previous stages of life (Puppy, Junior, and Adult groups). Differences in γδ T cells are significant and they are reported, for the first time, related to dog aging. Conclusions: The study confirms dogs to be among the animals with a low TCRγδ+ cell profile. A decrease of the TCRγδ+ subpopulation percentage was observed in elder dogs. TCRγδ+ cells of group S were different from those of groups P, J, and A. The differences are reported for the first time in dog aging. Identifying the stage of life when the decrease of γδ T lymphocytes starts can be useful for providing a rationale for drafting a wellness plan trial to support thymus immune functions and mitigate its functional exhaustion

    Apontamentos Sobre O Contexto Do Desenvolvimento Regional De Cubatão [sp]

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    Na gestão e aproveitamento da água, os aspectos culturais e econômicos são cruciais: determinam a postura dos atores sociais diante do precioso bem. Em áreas de precipitação intensa, como a região do município de Cubatão, Estado de São Paulo, Brasil, o cenário não é diferente: o bem é abundante, atraindo a atividade econômica, embora essa atividade econômica nem sempre consiga lidar de forma sustentável com esse mesmo bem. Este trabalho mostra alguns aspectos dessa difícil conjugação.43p.64-73Engenharia Civi
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