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91.
《Journal of Statistical Computation and Simulation》2012,82(1-3):87-113
An important problem in process adjustment using feedback is how often to sample the process and when and by how much to apply an adjustment. Minimum cost feedback schemes based on simple, but practically interesting, models for disturbances and dynamics have been discussed in several particular cases. The more general situation in which there may be measurement and adjustment errors, deterministic process drift, and costs of taking an observation, of making an adjustment, and of being off target, is considered in this article. Assuming all these costs to be known, a numerical method to minimize the overall expected cost is presented. This numerical method provides the optimal sampling interval, action limits, and amount of adjustment; and the resulting average adjustment interval, mean squared deviation from target, and minimum overall expected cost. When the costs of taking an observation, of making an adjustment, and of being off target are not known, the method can be used to choose a particular scheme by judging the advantages and disadvantages of alternative options considering the mean squared deviation they produce, the frequency with which they require observations to be made, and the resulting overall length of time between adjustments. Computer codes that perform the required computations are provided in the appendices and applied to find optimal adjustment schemes in three real examples of application. 相似文献
92.
M. Mushfiqur Rashid M. Mushfiqur Rashid James C. Aubuchon Ansuman Bagchi 《统计学通讯:理论与方法》2013,42(10):2783-2811
A rank-based inference is developed for repeated measures balanced incomplete block and randomized complete block designs using a suitable dispersion function. Asymptotic distributions of rank estimators are developed after establishing approximate linearity of the gradient vector of the dispersion function. Unlike available nonparametric procedures for those designs, estimation and testing are tied together. Three different test statistics are developed for testing the linear hypotheses. Friedman's (1937) statistic and Durbin's (1951) statistic are particular cases of one of the three proposed statistics. An estimate of a scale parameter which appears in the ARE expression as well as as in the variences and covariances of the rank estimators is discussed. 相似文献
93.
In this paper we have proposed chain ratio type estimators for ratio of two population means using two auxiliary characters. The expressions for bias and mean square error of these estimators have been derived. A comparison of the proposed estimator with that of double sampling estimator has been made in terms of mean square error. An emperical study has also been made. 相似文献
94.
《统计学通讯:理论与方法》2013,42(7):1517-1531
ABSTRACT Scale equivariant estimators of the common variance σ2, of correlated normal random variables, have mean squared errors (MSE) which depend on the unknown correlations. For this reason, a scale equivariant estimator of σ2 which uniformly minimizes the MSE does not exist. For the equi-correlated case, we have developed three equivariant estimators of σ2: a Bayesian estimator for invariant prior as well as two non-Bayesian estimators. We then generalized these three estimators for the case of several variables with multiple unknown correlations. In addition, we developed a system of confidence intervals which produce the desired coverage probability while being efficient in terms of expected length. 相似文献
95.
Recently, Shabbir and Gupta [Shabbir, J. and Gupta, S. (2011). On estimating finite population mean in simple and stratified random sampling. Communications in Statistics-Theory and Methods, 40(2), 199–212] defined a class of ratio type exponential estimators of population mean under a very specific linear transformation of auxiliary variable. In the present article, we propose a generalized class of ratio type exponential estimators of population mean in simple random sampling under a very general linear transformation of auxiliary variable. Shabbir and Gupta's [Shabbir, J. and Gupta, S. (2011). On estimating finite population mean in simple and stratified random sampling. Communications in Statistics-Theory and Methods, 40(2), 199–212] class of estimators is a particular member of our proposed class of estimators. It has been found that the optimal estimator of our proposed generalized class of estimators is always more efficient than almost all the existing estimators defined under the same situations. Moreover, in comparison to a few existing estimators, our proposed estimator becomes more efficient under some simple conditions. Theoretical results obtained in the article have been verified by taking a numerical illustration. Finally, a simulation study has been carried out to see the relative performance of our proposed estimator with respect to some existing estimators which are less efficient under certain conditions as compared to the proposed estimator. 相似文献
96.
赵朴 《石家庄铁道学院学报(社会科学版)》2009,(3):61-64
采用变量轮换法对支持向量机(SVM)参数进行优化处理,结合时间序列分析理论,建立起隧道围岩变形时间序列非线性模型,并以此对隧道围岩变形进行预测。结果表明:改进的支持向量机具有简单、方便、实时等特点,对围岩后续变形预报准确,可科学地指导现场监测和施工建设。 相似文献
97.
孙守春 《齐齐哈尔大学学报(哲学社会科学版)》2003,(3):5-8
孔子和亚里士多德分别是古代东西方最伟大的政治家、思想家 ,在东西方政治思想史上都占有极重要的地位。前人对他们政治思想的研究颇多 ,但对比研究则少 ,文章拟通过对他们政体理论的比较研究 ,找出东西方文化差异根源 相似文献
98.
提出了一种用支持向量机校正传感器非线性误差的原理和方法。该算法只依据样本就可以正确辩识传感器逆模型特征,而不需关于逆模型函数形式的任何先验知识,并将原问题转化为一个凸二次优化问题,能够保证找到的极值解就是全局最优解,具有较好的泛化能力。通过对电容式湿敏传感器误差校正的应用表明:该算法可取得较好的效果。 相似文献
99.
Many sufficient conditions for inequalities about the mean, median, mode and skewness have been obtained. The paper presents a theorem that unifies already known results, gives some counter-examples, and considers the cases of Pearson distributions. 相似文献
100.
杨建省 《内蒙古工业大学学报》1989,8(2):87-95
线性异或逻辑方程组现有的求解方法均不适于用计算机求解。为此,本文引入了逻辑矩阵的概念。本文对逻辑矩阵、逻辑向量系的相关性、Cramer法则等进行了理论证明或分析。 相似文献