共查询到20条相似文献,搜索用时 15 毫秒
1.
Summary The paper considers two examples in the two sample normal problem and finds noniformative priors which satisfy (i) a criterion
of matching asymptotically the posterior distribution function of a suitably normalized real-valued parameter of interest
with the corresponding frequentist distribution function, and (ii) avoid the marginalization paradox. These two considerations
lead to unique priors within certain classes for the two problems under consideration. In the first example, the prior turns
out to be the one-at-a time reference prior of Berger and Bernardo (1992a, 1992b), while in the second example, the prior
is outside the class of reference priors. 相似文献
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Under the uncertainty of market demand and quality of returns, sorting prior to disassembly is effective for timely obtaining information about the remanufacturability of used products. In this article, we assume that the remanufacturable fraction of used products is a random variable and introduce an inaccurate sorting procedure of used products prior to disassembly. Then, three two-stage optimization models are formulated to maximize the expected profits of a remanufacturer in a single period with used products and/or new parts as inputs to meet the stochastic market demand. Moreover, the article provides a case study to explore the optimal decisions under different scenarios and analyzes the effects of parameters, such as the unit disassembly cost, unit sorting cost, and proportion of sorting errors. Finally, the results indicate that whether remanufacturing with sorting is more profitable than that without sorting mainly depends on the sorting accuracy and the relative value between disassembly cost and sorting cost. When considering or not considering a long lead time of new parts, the effects of sorting errors on procurement policies are different. A long lead time will result in lower expected profits. Finally, the diverse types of classification errors have different influences on procurement policies and corresponding expected profit. 相似文献
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Summary A prior may be noninformative for one parameter at the cost of being informative for another parameter. This leads to the
idea of tradeoff priors: priors that give up noninformativity for some parameters to achieve noninformativity for others.
We propose a general framework where priors are selected by optimizing a functional with two components. The first component
formalizes the requirement that the optimal prior be noninformative for the parameter of interest. The second component is
a penalty term that forces the optimizing prior to be close to some target prior. Optimizing such a functional results in
a parameterized family of priors from which a specific prior may be selected as the tradeoff prior. An important particular
example of such functionals is provided by choosing the first term to be the marginal missing information for the parameter
of interest (generalizing Bernardo’s notion of missing information) and the second term to be the relative entropy between
the unknown prior and the Jeffreys prior. In this case we find a closed form expression for the tradeoff prior and we make
explicit connections with the Berger-Bernardo prior. In particular, we show that under certain conditions, the Berger-Bernardo
prior and the Jeffreys prior are special cases of the tradeoff prior. We consider several examples. 相似文献
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借助准标样测算拉伸试验测量不确定度的方法 总被引:2,自引:0,他引:2
为了可靠地对拉伸试验相关检测项目的测量不确定度进行评定,借鉴国际硬度试验标准草案中测量不确定度评定的方法,介绍了一种以标准物质实测结果为基础的计算屈服强度Rp0.2、抗拉强度Rm和最大力总伸长率Agt的测量不确定度的方法。 相似文献
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Summary In the linear calibration problem, a model is fit to paired observations arising from two measurement techniques, one known
to be far more accurate (but also more expensive) than the other. The fitted model is then used with univariate observations
from the less accurate technique to impute values from the more accurate one. The Bayesian paradigm emerges as attractive
in this context, but the choice of an appropriate noninformative prior distribution has been controversial. In this paper
we derive a class of such distributions, and provide sufficient conditions under which they lead to proper posterior densities.
These priors, which we refer to asprobability matching priors, are designed to produce posterior credible intervals which are asymptotically identical to their frequentist counterparts.
We provide details on the implementation of our procedure using sampling-based methods, and obtain significant simplifications
over previous Bayesian approaches in this area. We compare the performance of several members of our prior class in the context
of two illustrative examples. 相似文献
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为解决在测定材料冲击吸收功出现用户验收结果与出厂检验结果不一致的问题,提出了用准标样测算冲击试验测量不确定度的方法。这种方法可作为双方在进行冲击值比对分析时都能接受的评定方法。 相似文献
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A new uncertainty importance measure 总被引:19,自引:0,他引:19
Uncertainty in parameters is present in many risk assessment problems and leads to uncertainty in model predictions. In this work, we introduce a global sensitivity indicator which looks at the influence of input uncertainty on the entire output distribution without reference to a specific moment of the output (moment independence) and which can be defined also in the presence of correlations among the parameters. We discuss its mathematical properties and highlight the differences between the present indicator, variance-based uncertainty importance measures and a moment independent sensitivity indicator previously introduced in the literature. Numerical results are discussed with application to the probabilistic risk assessment model on which Iman [A matrix-based approach to uncertainty and sensitivity analysis for fault trees. Risk Anal 1987;7(1):22–33] first introduced uncertainty importance measures. 相似文献
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表面粗糙度评定的小波基准线 总被引:13,自引:0,他引:13
给出了一条新的粗糙度评定基准线———小波基准线。此线是曲面轮廓线、形位误差及波纹度等低频信号的综合。与传统的评定基准线相比,其优点是:光滑自然,没有特定的函数形式;由数据的小波分解产生,精度高。 相似文献
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《TEST》1980,31(1):605-647
Summary The procedure of maximizing the missing information is applied to derive reference posterior probabilities for null hypotheses.
The results shed further light on Lindley’s paradox and suggest that a Bayesian interpretation of classical hypothesis testing
is possible by providing a one-to-one approximate relationship between significance levels and posterior probabilities. 相似文献
14.
The Reference Gauge technique for static expansion ratios—Applied to NPL medium vacuum standard SEA3
John Greenwood 《Vacuum》2006,81(4):427-433
Static expansion pressure standards are typically characterised in terms of the ratio between the density of an expanded sample of gas and that of an initial sample. For standards that perform a series of expansions through several system vessels most of the existing techniques to measure this expansion ratio involve disturbance to the system. They usually also involve operation with higher pressures and with valve sequences that are not encountered under normal operational conditions, thereby introducing the risk of systematic errors. A modification of the Reference Gauge technique for expansion ratios is described which has none of these disadvantages. The technique is described with reference to the medium vacuum standard SEA3 at the UK National Physical Laboratory. 相似文献
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《Advanced Powder Technology》2014,25(6):1748-1753
In order to confirm reliable particle size measurement technique and to prepare standard reference particles for calibrating particle size measurement devices, uncertainty region of count and mass based size distribution have been theoretically examined. The uncertainty region of count base cumulative size distribution is smaller than that of the mass base cumulative distribution.The uncertainty region of count base cumulative size distribution is nearly constant over wide range of particle diameter and the region is nearly constant for sample size greater than about 20,000.On the other hand, the uncertainty region of mass base cumulative distribution increases with the increase of particle diameter.The reliability of theoretical uncertainty region is confirmed by the experimental data of particle size measurement. 相似文献
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Paul A. Miller Gregory A. Hebner Kenneth E. Greenberg Paul D. Pochan Ben P. Aragon 《Journal of research of the National Institute of Standards and Technology》1995,100(4):427-439
In order to extend the operating range of the GEC RF Reference Cell, we developed an inductively coupled plasma source that replaced the standard parallel-plate upper-electrode assembly. Voltage and current probes, Langmuir probes, and an 80 GHz interferometer provided information on plasmas formed in argon, chlorine, and nitrogen at pressures from 0.1 Pa to 3 Pa. For powers deposited in the plasma from 20 W to 300 W, the source produced peak electron densities between 1010/cm3 and 1012/cm3 and electron temperatures near 4 eV. The electron density peaked on axis with typical full-width at half maximum of 7 cm to 9 cm. Discharges in chlorine and nitrogen had bimodal operation that was clearly evident from optical emission intensity. A dim mode occurred at low power and a bright mode at high power. The transition between modes had hysteresis. After many hours of high-power operation, films formed on electrodes and walls of one Cell. These deposits affected the dim-to-bright mode transition, and also apparently caused generation of hot electrons and increased the plasma potential. 相似文献
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