Beyond Wiener–Askey Expansions: Handling Arbitrary PDFs

In this paper we present a Multi-Element generalized Polynomial Chaos (ME-gPC) method to deal with stochastic inputs with arbitrary probability measures. Based on the decomposition of the random space of the stochastic inputs, we construct numerically a set of orthogonal polynomials with respect to a conditional probability density function (PDF) in each element and subsequently implement generalized Polynomial Chaos (gPC) locally. Numerical examples show that ME-gPC exhibits both p- and h-convergence for arbitrary probability measures     

Water quality surveys: A statistical method based on determinism, quantiles and the binomial distribution

A statistical method for surveying water quality and analysing the results in terms of quantiles is described. The value of a water quality variable in a grab-sample is taken as a deterministic function of the temporal and spatial coordinates of the sampling point. Quantiles can then be defined for any specified region in time and space as unique, fixed values, and randomly located grab-samples may be used to estimate them for the purposes of describing or regulating water quality. Robust statistical inferences are possible using the binomial distribution. Properties of the quantiles, confidence limits, comparisons with fixed values or between regions, assessment of trends, simultaneous inferences and estimation of sample sizes are discussed. Two examples of water quality surveys, one of Port Phillip Bay, the other of the Maribyrnong River, Victoria, are used to illustrate the theory, paying particular attention to practical problems which arose. The proposed method is compared with others based on stochastic models, and is claimed to be simpler and more reliable.     

A time series approach to fatigue crack propagation

The inherently nonlinear phenomenon of fatigue crack propagation is modeled as a linear random process. To a first approximation, simple, nonstationary time series models are introduced and standard techniques for determining the parameters of autoregressive integrated moving-average processes are applied. Multiplicative time series models are next utilised for the representation of a group of crack history curves. Implementation of the models on the Virkler experimental data set yields satisfactory results. Reliable Gaussian approximations to the distribution of the time required by a crack to reach a specified critical length are obtained, and the usefulness of the approach is demonstrated when updating lifetime predictions after periodic inspections.     

数字电视技术的内涵及发展趋势

以有线电视为重点介绍了电视信号的数字化概念、优点及数字电视发展的趋势     

利用单片机80c196kc实现等间隔采样及采样值的回显

本文主要介绍以单片机80c196kc为CPU对模拟信号进行等间隔采样以及实现对采样值回显的问题。详细介绍了测频软件及电路的实现，对等间隔采样软件实现进行了详细论述：详尽讨论了对于MG-12864-2液晶显示器的电路连接与软件控制方法；对MG-12864-2液晶显示器应用的独特之处做了细致的分析。     

Mixture of probability distributions as a basic component in simulating measurement accuracy

A stochastic model is proposed for a basic mechanism in the formation of uncertainties in physical quantity measurements. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 12–17, January, 2006.     

A general variance predictor for Cavalieri slices

A general variance predictor is presented for a Cavalieri design with slices of an arbitrary thickness t ≥ 0. So far, prediction formulae have been available either for measurement functions with smoothness constant q = 0, 1, … , and t ≥ 0, or for fractional q ∈ [0, 1] with t = 0. Because the possibility of using a fractional q adds flexibility to the variance prediction, we have extended the latter for any q ∈ [0, 1] and t ≥ 0. Empirical checks with previously published human brain data suggest an improved performance of the new prediction formula with respect to the hitherto available ones.     

Method of Reducing Error in Calculations of Active Power from Signal Samples

The paper presents the results of investigations into several methods of calculating the active power value from current and voltage signal samples. The accuracy attainable for nonsinusoidal signals whose frequency differs from the nominal one was determined. A new active power calculation method ensuring accurate results for sampling over two signal periods is proposed. The method uses a very simple computing algorithm.     

Design of thermophoretic probe for precise particle sampling

We proposed a design methodology for improved thermophoretic probes that can sample particles with high spatial resolution. A bending vibration analysis for the instantaneous motion of a probe has been done together with direct observation of the probe motion and flow disturbance for systematic study of the effect of different designs on particle sampling. Direct observation of the motion of thermophoretic sampling probes revealed that the probe with a low stiffness would result in inaccurate particle sampling. Based on these, the thermophoretic sampling probe was modified to minimize probe vibration and flow disturbance and this modified design was confirmed to sample particles with higher spatial resolution than the original one by examining transmission electron microscope (TEM) images of particles collected in a flame.     

Effect of plate aspect ratio on the recovery of deuterium from water-isotope mixture in flat-plate thermal diffusion columns with transverse sampling streams

The optimal plate aspect ratios for the best recovery of deuterium from water-isotope mixture in flat-plate thermal diffusion columns with transverse sampling streams have been determined. The maximum recovery and maximum production rate are achieved without changing the total expenditure, while the design with minimum plate surface area results in minimizing the total expense.