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161.
162.
Fisher最优分割法在星星哨水库汛期分期划分中的应用 总被引:1,自引:0,他引:1
Fisher最优分割法是对有序样本进行最优化分段的一种数学方法。本文利用该方法对星星哨水库汛期进行相应的划分,结果表明该方法是可行的。因此,可利用该结果对分期实施不同的汛限水位,使水库的防洪和兴利效益达到最大。 相似文献
163.
164.
Cost estimates to guide pre-selection of processes 总被引:2,自引:0,他引:2
A process is a method of shaping, joining or surface-treating a material. Process selection has three steps. The first is to identify from the ‘menu’ of all available processes, the subset, which can give a chosen material the desired shape with the desired detail, precision and finish. The second is to choose, from among these, the ones that will do so at the lowest cost. The final step is to investigate the most promising processes in depth, exploring considerations such as availability, in-house experience, safety and environmental issues. The first two steps can be thought of as process pre-selection. Components have to be assembled and finished to create products. Here too, the ability to rank by cost, however crudely, helps guide pre-selection. Cost models are reviewed from the perspective of material and process selection. An approximate model is useful provided it has generality—that is, it must allow comparison of very different processes. Many approaches fail in this. One that works, based on resource consumption, is developed here and its use for selection is illustrated. It has been implemented as part of a tool that allows rapid pre-selection from a database of 112 processes. 相似文献
165.
一种空间自适应小波门限去噪算法 总被引:3,自引:0,他引:3
提出了一种空间自适应小波门限去噪算法,该算法在小波域对含噪小波系数做两次自适应去噪,两次自适应门限分别基于最大似然(ML)方差估计和最大后验概率(MAP)方差估计.仿真结果表明,该算法与其它自适应门限去噪算法相比,去噪后的图象具有更高的峰值信噪比(PSNR). 相似文献
166.
167.
Bayesian and Dempster-Shafer fusion 总被引:3,自引:0,他引:3
The Kalman Filter is traditionally viewed as a prediction-correction filtering algorithm. In this work we show that it can
be viewed as a Bayesian fusion algorithm and derive it using Bayesian arguments. We begin with an outline of Bayes theory,
using it to discuss well-known quantities such as priors, likelihood and posteriors, and we provide the basic Bayesian fusion
equation. We derive the Kalman Filter from this equation using a novel method to evaluate the Chapman-Kolmogorov prediction
integral. We then use the theory to fuse data from multiple sensors. Vying with this approach is the Dempster-Shafer theory,
which deals with measures of “belief”, and is based on the nonclassical idea of “mass” as opposed to probability. Although
these two measures look very similar, there are some differences. We point them out through outlining the ideas of the Dempster-Shafer
theory and presenting the basic Dempster-Shafer fusion equation. Finally we compare the two methods, and discuss the relative
merits and demerits using an illustrative example. 相似文献
168.
基于物质平衡方程、产能方程和递减方程的结合,提出了定容气田开发规划的概算法.该法可用于预测地层压力、井底流动压力、井口流动压力和稳产年限.实际应用表明,本文提供的方法是实用有效的. 相似文献
169.
Compositional data occur as natural realizations of multivariate observations comprising element proportions of some whole
quantity. Such observations predominate in disciplines like geology, biology, ecology, economics and chemistry. Due to unit
sum constraint on compositional data, specialized statistical methods are required for analyzing these data. Dirichlet distributions
were originally used to study compositional data even though this family of distribution is not appropriate (see Aitchison,
1986) because of their extreme independence properties. Aitchison (1982) endeavored to provide a viable alternative to existing
methods by employing Logistic Normal distribution to analyze such constrained data. However this family does not include the
Dirichlet class and is therefore unable to address the issue of extreme independence. In this paper generalized Liouville
family is investigated to model compositional data which includes covariates. This class permits distributions that admit
negative or mixed correlation and also contains non-Dirichlet distributions with non-positive correlation and overcomes deficits
in the Dirichlet class. Semiparametric Bayesian methods are proposed to estimate the probability density. Predictive distributions
are used to assess performance of the model. The methods are illustrated on a real data set. 相似文献
170.
N. V. Khovanov 《Measurement Techniques》2007,50(3):255-258
A Bayesian model is proposed based on randomizing the systematic errors of the instruments. Conditions are identified under
which the randomization reduces the expected bias in estimating a measured quantity.
__________
Translated from Izmeritel’naya Tekhnika, No. 3, pp. 22–25, March, 2007. 相似文献