The present work examines the applicability of the joint transported probability density function (TPDF) with the velocity field obtained from a conventional RANS k-epsilon approach in a jet-stirred reactor, where the...
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The present work examines the applicability of the joint transported probability density function (TPDF) with the velocity field obtained from a conventional RANS k-epsilon approach in a jet-stirred reactor, where the Damk & ouml;hler number is below the unity. In the TPDF equation, turbulent transport is handled with a conventional k-epsilon gradient transport assumption and the LMSE is used for the molecular mixing. Through the use of a dynamic model for the mixing time-scale, by computing the individual time-scales for the reactive scalars dynamically in each cell during the course of the simulation using the RANS-TPDF code. The chemical reaction is described by a reduced and detailed chemical propane mechanism. The modelized PDF equation constants are determined from the available experimental data conducted by using fine wire thermo-anemometry. The CFD-TPDF predictions were within engineering accuracy of experimental data. It can be summarized that the results of exercise are satisfactory, and the CPU-time and RAM memory savings encouraging.
In this Letter, the authors present a closed-form derivation of the probability density function (PDF) for the notch depth (ND) of the dominant mode rejection adaptive beamformer (ABF). Their PDF expression closely ap...
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In this Letter, the authors present a closed-form derivation of the probability density function (PDF) for the notch depth (ND) of the dominant mode rejection adaptive beamformer (ABF). Their PDF expression closely approximates the true PDF for the case of single interferer at reasonable levels of interference-to-noise ratio. Their simulation results illustrate the close approximation between proposed distribution function and the ND histogram over a wide range of snapshots for fixed number of sensors.
A probabilistic description of field coupling onto a uniform, lossless, multiconductor transmission line (MTL) is presented. Based on the assumption of low frequency, the probability density function of the voltage ma...
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A probabilistic description of field coupling onto a uniform, lossless, multiconductor transmission line (MTL) is presented. Based on the assumption of low frequency, the probability density function of the voltage magnitude across the loads is analytically derived in the special case of a perfectly matched MTL, for a horizontally polarised wave, with random direction of incidence and amplitude.
The first-order probabilitydensity at the output of the correlation network of the delay-lock discriminator is determined using the methods developed by Arthur, Kac, and Siegert. The analysis assumes that the input s...
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The first-order probabilitydensity at the output of the correlation network of the delay-lock discriminator is determined using the methods developed by Arthur, Kac, and Siegert. The analysis assumes that the input signal is stationary and Gaussian and that the discriminator is locked on. No restrictions are made on the bandpass filter characteristics in the channels.
This paper deals with the probability density functions of quotient of order statistics. We use the Mellin transform technique, to find the distribution of the quotient Z= X/Xwhere X.,X(i < j) are the ith and jth o...
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This paper deals with the probability density functions of quotient of order statistics. We use the Mellin transform technique, to find the distribution of the quotient Z= X/Xwhere X.,X(i < j) are the ith and jth order statistics from the Pareto, Power and Weibull distributions
The streamwise and the spanwise velocity time series are measured from the wall to the centre of the cross duct for the flow in a rectangular T-junction duct, which is similar to airflow conditions of high-speed train...
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The streamwise and the spanwise velocity time series are measured from the wall to the centre of the cross duct for the flow in a rectangular T-junction duct, which is similar to airflow conditions of high-speed train ventilation system. The turbulent statistical properties are reported at three streamwise locations which correspond to the upstream/downstream and the centreline of the T-junction (x/D=+/- 1 and 0, respectively). Turbulence intensities, skewness and flatness factor, as well as probability density functions, have been investigated at the range of Re=5400-8700. Furthermore, the multiscale properties of the flatness factor are analysed by using orthogonal wavelet transform. It is found that the turbulent intensities remain a constant in the centre region for three streamwise locations while they are weakened in the turbulent boundary layer at x/D=1 by effect of suction. The location of the strongest intermittency is located at y/h=0.56 for x/D=-1 and 0. While at downstream of T-junction (x/D=1), the location of the strongest intermittency shifts down to y/h=0.28. Also, the wavelet flatness factor is more clearly distinguished the intermittency of the small-scale turbulent structure compared with the conventional flatness factor and, the obtained experimental data are fitted and used to predict the mean streamwise velocity profiles.
The turbulence fluctuation spectra of linear magnetized plasmas are measured under various neutral pressure conditions. Strong turbulent waves and symmetric waves are observed in low and high neutral pressure conditio...
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The probability density function (PDF) describes the fraction of time an electrogram signal spends at the baseline. In normal rhythm the signal is at baseline during the period between electrogram complexes, while in ...
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The probability density function (PDF) describes the fraction of time an electrogram signal spends at the baseline. In normal rhythm the signal is at baseline during the period between electrogram complexes, while in fibrillation the signal exhibits continuous activity and spends little time at baseline. However, time spent at the baseline is dependent on the rate of the rhythm, which limits the ability of the PDF algorithm to discriminate ventricular fibrillation from fast nonfibrillatory rhythms. A cycle length corrected version of the PDF algorithm has been formulated, which only examines the electrical activity between detected beats. The algorithm was developed utilizing a training set of 77 endocardial recordings and tested utilizing a test set of 90 endocardial and 56 epicardial recordings. Ventricular fibrillation was detected with 100% sensitivity and 98% specificity.
A novel probability density function (PDF) estimation based over-sampling approach is proposed for two-class imbalanced classification problems. The Parzen-window kernel function is applied to estimate the PDF of the ...
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ISBN:
(纸本)9781467314909
A novel probability density function (PDF) estimation based over-sampling approach is proposed for two-class imbalanced classification problems. The Parzen-window kernel function is applied to estimate the PDF of the positive class, from which synthetic instances are generated as additional training data to re-balance the class distribution. Utilising the re-balanced over-sampled training data, a radial basis function (RBF) classifier is constructed by applying an orthogonal forward regression, in which the classifier's structure and the parameters of RBF kernels are determined using a particle swarm optimisation algorithm based on the criterion of minimising the leave-one-out misclassification rate. The effectiveness of the proposed approach is demonstrated by an empirical study on several imbalanced data sets.
The use of Fisher ratio (FR) algorithm to predict a pattern in an input seen has been applied in several applications in the literature with different success rate, depending on how close is the similarity of the stat...
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ISBN:
(纸本)9780819471680
The use of Fisher ratio (FR) algorithm to predict a pattern in an input seen has been applied in several applications in the literature with different success rate, depending on how close is the similarity of the statistical parameters between the background and the patterns. We propose a modification to the FR ratio algorithm that is dependent on the probability density function (PDF). The modified PDF-FR algorithm provides good improvements over that of the PDF used alone. We further enhance the performance of the PDF-FR using polarization-enhanced imagery.
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