79 research outputs found

    On the performance of existing acoustic energy models when applied to multi-purpose performance halls

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    Acoustical measurements were done in two multi-purpose performance halls in the present study. The measured data are compared with predictions from three acoustic energy models in existing literature derived for churches and large reverberant theatres. Results show that the model suitable for the present multi-purpose performance halls is the one which takes into account the time difference between direct sound arrival and onset time of reverberant sound decay. However, unlike the church cases, the time difference appears to have no direct definite relationship with the source-receiver distance alone. A method for the prediction of time difference is then proposed for multi-purpose performance hall application. In addition, the prediction of the late reflected energy is not satisfactory, and this deficiency is the main problem leading to the inaccurate estimation of clarity, definition and centre time in the present study

    Decoupled and Analytical Model of the Quad-Active-Bridge DC/DC Wind Converter under Transmitting Instantaneous Pulsating Power

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    The quad-active-bridge (QAB) DC/DC converter has shown superior advantages in eliminating the low-frequency voltage ripple in the cascaded wind power converter. However, the power flowing into the QAB converter contain low-frequency pulsation, causing low-frequency envelope oscillation issues inside the QAB converter. This paper proposes a decoupled and analytical model for quantitively analysis of the corresponding operation characteristics. Specifically, a summation difference transformation is proposed to decouple the multivariable coupling model as a diagonal decoupled model. The QAB converter voltages with time-varying angles are decomposed as the supervision of multiple frequency components by the Bessel function. Various characteristics such as input current stress (peak and rms), low-frequency envelope oscillations have been thoroughly analyzed under instantaneous pulsating power transmission with the proposed model. These results can be further used for designing more high-performance control strategies to optimize operation. Simulation and experimental results are presented to validate the proposed analytical model

    Decoupled and Analytical Model of the Quad-Active-Bridge DC/DC Wind Converter under Transmitting Instantaneous Pulsating Power

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    The quad-active-bridge (QAB) DC/DC converter has shown superior advantages in eliminating the low-frequency voltage ripple in the cascaded wind power converter. However, the power flowing into the QAB converter contain low-frequency pulsation, causing low-frequency envelope oscillation issues inside the QAB converter. This paper proposes a decoupled and analytical model for quantitively analysis of the corresponding operation characteristics. Specifically, a summation difference transformation is proposed to decouple the multivariable coupling model as a diagonal decoupled model. The QAB converter voltages with time-varying angles are decomposed as the supervision of multiple frequency components by the Bessel function. Various characteristics such as input current stress (peak and rms), low-frequency envelope oscillations have been thoroughly analyzed under instantaneous pulsating power transmission with the proposed model. These results can be further used for designing more high-performance control strategies to optimize operation. Simulation and experimental results are presented to validate the proposed analytical model

    Intranasal Delivery of Cationic PLGA Nano/Microparticles- Loaded FMDV DNA Vaccine Encoding IL-6 Elicited Protective Immunity against FMDV Challenge

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    Mucosal vaccination has been demonstrated to be an effective means of eliciting protective immunity against aerosol infections of foot and mouth disease virus (FMDV) and various approaches have been used to improve mucosal response to this pathogen. In this study, cationic PLGA (poly(lactide-co-glycolide)) nano/microparticles were used as an intranasal delivery vehicle as a means administering FMDV DNA vaccine encoding the FMDV capsid protein and the bovine IL-6 gene as a means of enhancing mucosal and systemic immune responses in animals. Three eukaryotic expression plasmids with or without bovine IL-6 gene (pc-P12A3C, pc-IL2AP12A3C and pc-P12AIL3C) were generated. The two latter plasmids were designed with the IL-6 gene located either before or between the P12A and 3C genes, respectively, as a means of determining if the location of the IL-6 gene affected capsid assembly and the subsequent immune response. Guinea pigs and rats were intranasally vaccinated with the respective chitosan-coated PLGA nano/microparticles-loaded FMDV DNA vaccine formulations. Animals immunized with pc-P12AIL3C (followed by animals vaccinated with pc-P12A3C and pc-IL2AP12A3C) developed the highest levels of antigen-specific serum IgG and IgA antibody responses and the highest levels of sIgA (secretory IgA) present in mucosal tissues. However, the highest levels of neutralizing antibodies were generated in pc-IL2AP12A3C-immunized animals (followed by pc-P12AIL3C- and then in pc-P12A3C-immunized animals). pc-IL2AP12A3C-immunized animals also developed stronger cell mediated immune responses (followed by pc-P12AIL3C- and pc-P12A3C-immunized animals) as evidenced by antigen-specific T-cell proliferation and expression levels of IFN-γ by both CD4+ and CD8+ splenic T cells. The percentage of animals protected against FMDV challenge following immunizations with pc-IL2AP12A3C, pc-P12AIL3C or pc-P12A3C were 3/5, 1/5 and 0/5, respectively. These data suggested that intranasal delivery of cationic PLGA nano/microparticles loaded with various FMDV DNA vaccine formulations encoding IL-6 as a molecular adjuvant enhanced protective immunity against FMDV, particularly pc-IL2AP12A3C with IL-6 gene located before P12A3C gene

    Efficient Shapelet Discovery for Time Series Classification

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    Time-series shapelets are discriminative subsequences, recently found effective for time series classification (tsc). It is evident that the quality of shapelets is crucial to the accuracy of tsc. However, major research has focused on building accurate models from some shapelet candidates. To determine such candidates, existing studies are surprisingly simple, e.g., enumerating subsequences of some fixed lengths, or randomly selecting some subsequences as shapelet candidates. The major bulk of computation is then on building the model from the candidates. In this paper, we propose a novel efficient shapelet discovery method, called bspcover, to discover a set of high-quality shapelet candidates for model building. Specifically, bspcover generates abundant candidates via Symbolic Aggregate approXimation with sliding window, then prunes identical and highly similar candidates via Bloom filters, and similarity matching, respectively. We next propose a ppp-Cover algorithm to efficiently determine discriminative shapelet candidates that maximally represent each time-series class. Finally, any existing shapelet learning method can be adopted to build a classification model. We have conducted extensive experiments with well-known time-series datasets and representative state-of-the-art methods. Results show that bspcover speeds up the state-of-the-art methods by more than 70 times, and the accuracy is often comparable to or higher than existing works

    Evolutionary Analysis of Structural Protein Gene VP1 of Foot-and-Mouth Disease Virus Serotype Asia 1

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    Foot-and-mouth disease virus (FMDV) serotype Asia 1 was mostly endemic in Asia and then was responsible for economically important viral disease of cloven-hoofed animals, but the study on its selection and evolutionary process is comparatively rare. In this study, we characterized 377 isolates from Asia collected up until 2012, including four vaccine strains. Maximum likelihood analysis suggested that the strains circulating in Asia were classified into 8 different groups (groups I–VIII) or were unclassified (viruses collected before 2000). On the basis of divergence time analyses, we infer that the TMRCA of Asia 1 virus existed approximately 86.29 years ago. The result suggested that the virus had a high mutation rate (5.745 × 10−3 substitutions/site/year) in comparison to the other serotypes of FMDV VP1 gene. Furthermore, the structural protein VP1 was under lower selection pressure and the positive selection occurred at many sites, and four codons (positions 141, 146, 151, and 169) were located in known critical antigenic residues. The remaining sites were not located in known functional regions and were moderately conserved, and the reason for supporting all sites under positive selection remains to be elucidated because the power of these analyses was largely unknown
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