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991.
The pointwise error of a finite‐difference calculation of supersonic flow is discussed. The local truncation error is determined by a Taylor series with the remainder being in a Lagrange form. The contribution of the local truncation error to the total pointwise approximation error is estimated via adjoint parameters. It is demonstrated by numerical tests that the results of the numerical calculation of gasdynamics parameter at an observation point may be refined and an error bound may be estimated. The results of numerical tests for the case of parabolized Navier–Stokes are presented as an illustration of the proposed method. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
992.
The velocity component effect to the mass resolution was considered for two different positions of beam source in the time-of-flight
mass spectrometer based on de Heer and Milani criteria. The results estimated for various potassium cluster sizes showed that
resolution is reduced at considerable level and the cluster range is limited to the small mass sizes for the position along
with the cluster beam axis. The resolution is high and the effect appears close to K1000 cluster sizes depending upon perpendicular axis used. 相似文献
993.
Döhler Sebastian Rüschendorf Ludger 《Statistical Inference for Stochastic Processes》2003,6(3):291-307
We prove that the empirical L
2-risk minimizing estimator over some general type of sieve classes is universally, strongly consistent for the regression
function in a class of point process models of Poissonian type (random sampling processes). The universal consistency result
needs weak assumptions on the underlying distributions and regression functions. It applies in particular to neural net classes
and to radial basis function nets. For the estimation of the intensity functions of a Poisson process a similar technique
yields consistency of the sieved maximum likelihood estimator for some general sieve classes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
994.
多元GARCH模型的估计一般采用拟极大似然法(quasi maximum likehood),对于这种方法估计的相合性及渐近正态性已经被很多学者证实,然而对于新息列的分布不是多元正态时,这种估计的有效性还没人研究,本文从拟极大似然估计得到的参数相合估计入手,提出用非参数方法估计多元新息列的分布. 相似文献
995.
Changhua Chen Richard A. Davis Peter J. Brockwell 《Journal of multivariate analysis》1996,57(2):175-190
LetX1, …, Xnbe observations from a multivariate AR(p) model with unknown orderp. A resampling procedure is proposed for estimating the orderp. The classical criteria, such as AIC and BIC, estimate the orderpas the minimizer of the function[formula]wherenis the sample size,kis the order of the fitted model, Σ2kis an estimate of the white noise covariance matrix, andCnis a sequence of specified constants (for AIC,Cn=2m2/n, for Hannan and Quinn's modification of BIC,Cn=2m2(ln ln n)/n, wheremis the dimension of the data vector). A resampling scheme is proposed to estimate an improved penalty factorCn. Conditional on the data, this procedure produces a consistent estimate ofp. Simulation results support the effectiveness of this procedure when compared with some of the traditional order selection criteria. Comments are also made on the use of Yule–Walker as opposed to conditional least squares estimations for order selection. 相似文献
996.
基于无失效数据的可靠度的估计 总被引:2,自引:1,他引:1
韩明 《纯粹数学与应用数学》2002,18(2):165-169
对二项分布无失效数据,在可靠度的先验密度为且时,给出了可靠度的多层Bayes估计. 相似文献
997.
孙东松 《Chinese Journal of Lasers》2002,11(4):296-300
1 Introduction Developingaccurateactiveremotesensorsforglobalwindmeasurementhaslongbeenahighpriorityneedforbothclimatestudiesandweatherprediction[1] .Sofarmostofthewinddatacomefromtwosources:thefirstsourceisfromweatherballoons ,buttheproblemisthattherea… 相似文献
998.
Hssaine Amamou Andre BoisBelkacem Ferhat Roland RedonBruno Rossetto Pascal Matheron 《Journal of Quantitative Spectroscopy & Radiative Transfer》2002,75(6):747-763
Expressions for fundamental spectral line parameters are reported for Gaussian and Lorentzian shape profiles for homogeneous plasma at equilibrium in presence of the self-absorption. These expressions for Lorentzian profiles are applied to the determination of the ratios of transition probabilities and the ratios of optical thicknesses by a new method that we propose in this article. The self-absorption is computed by spectral line profiles with a Simplex algorithm program fitting. Applications to some experimental lines illustrate the appropriate corrections. 相似文献
999.
1000.
王建稳 《数学的实践与认识》2005,35(7):155-158
受有序样品聚类思想的启发,针对期权定价模型中的Possion跳—扩散模型,提出了一种基于标的资产价格历史数据的参数估计方法,并得到了较好的结果. 相似文献