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471.
V.K. Sharma 《Revue canadienne de statistique》1977,5(1):121-132
This paper presents a unified method of constructing change-over designs that permit the estimation of direct effects orthogonal to all other effects when the residual effects of treatments last for two consecutive periods. Explicit methods of analysis of these designs have been obtained for the situations where the first period observations are omitted from the analysis and where the first period observations are included. 相似文献
472.
提出了一种新颖的以灰度图像为水印的数字水印算法.首先利用正交小波变换对原始图像进行分解,然后借鉴传统的叠加思想,根据小波变换后,高低频分量的特点,将图像水印嵌入到小波域的低频部分.由于整个嵌入过程中,对原始图像没有进行任何改变,因此绝对保证了原图像的质量.水印的嵌入和提取都在密钥控制之下,可以较好地解决版权争议等问题.实验结果证明该算法对常见的图像处理操作和几何攻击有很强的鲁棒性. 相似文献
473.
美国英语的异质性及文化同质 总被引:1,自引:0,他引:1
姜光辉 《南京农业大学学报(社会科学版)》2006,6(1):82-85
美国英语是该国的社会和文化发展的产物,在许多方面都有别于英国英语。语言是文化的载体符号,它既反映文化又影响文化,同时也离不开文化的支撑。美国英语的变异程度很大,混杂的美国文化在美国英语的引导下,逐渐走向统一,凸显了文化的同质性。 相似文献
474.
T. P. Davis 《Lifetime data analysis》1995,1(3):275-306
Smith (1991) presents a paper proposing the use of Weibull regression models to establish dependence of failure data (usually times) on covariates related to the design of the test specimens and test procedures. In his article Smith made the point that good experimental design was as important in reliability applications as elsewhere, and in view of the current interest in design inspired by Taguchi and others, we pay some attention in this article to that topic. A real case study from the Ford Motor Company is presented.Our main approach is to utilize suggestions in the literature for applying standard least squares techniques of experimental analysis even when there is likely to be nonnormal error, and censoring. This approach lacks theoretical justification, but its appeal is its simplicity and flexibility. For completeness we also include some analysis based on the proportional hazards model, and in an attempt to link back to Smith (1991), look at a Weibull regression model. 相似文献
475.
给出了采用导引符号辅助相干解调的自适应调制正交频分复用系统模型,分析了导引符号辅助相干解调自适应调制正变频分复用系统频谱效率的定义和计算方法,并结合具体实例得到了数值结果。结果表明,在分析和计算频谱效率时,必须考虑接收端非理想信道估计和系统开销的影响,得到的结果才具有实际意义。 相似文献
476.
陈泽均 《电子科技大学学报(社会科学版)》1989,(2)
本文引入运动坐标,将复杂的边界条件展为傅里叶级数,并选择适当的坐标参量,用分离变量法导出了采用图案型偏转轮的摄象管的聚焦、投射和扫描(FPS)系统空间电位分布的形式简洁的严格解。并在统一坐标系下,求出了磁场分布。本文的解克服了以往文献的解的结构复杂和计算量大的弱点,使得可用解析法求出FPS系统的特性参量和在小型计算机上实现FPS系统的最优化设计。 相似文献
477.
S.K. Zaremba 《Statistics》2013,47(4):625-642
The J* test which was previously proposed by the present author for the detection of a trend in a time series does not depend on any quantitative assumptions, but in the case of a polynomial trend it depends on its degree; if this degree is too high, the test cannot be applied. The author finds a bound of the significance level at which the test can be applied when the sample size, as well as a bound of the degree of the trend, are given. Asymptotic results are used only when we trust the asymptotic distribution of J* under the null hypothesis. 相似文献
478.
Marten H. Wegkamp 《Revue canadienne de statistique》1999,27(2):409-420
Let f?n, h denote the kernel density estimate based on a sample of size n drawn from an unknown density f. Using techniques from L2 projection density estimators, the author shows how to construct a data-driven estimator f?n, h which satisfies This paper is inspired by work of Stone (1984), Devroye and Lugosi (1996) and Birge and Massart (1997). 相似文献
479.
Parameter estimation for association and log-linear models is an important aspect of the analysis of cross-classified categorical data. Classically, iterative procedures, including Newton's method and iterative scaling, have typically been used to calculate the maximum likelihood estimates of these parameters. An important special case occurs when the categorical variables are ordinal and this has received a considerable amount of attention for more than 20 years. This is because models for such cases involve the estimation of a parameter that quantifies the linear-by-linear association and is directly linked with the natural logarithm of the common odds ratio. The past five years has seen the development of non-iterative procedures for estimating the linear-by-linear parameter for ordinal log-linear models. Such procedures have been shown to lead to numerically equivalent estimates when compared with iterative, maximum likelihood estimates. Such procedures also enable the researcher to avoid some of the computational difficulties that commonly arise with iterative algorithms. This paper investigates and evaluates the performance of three non-iterative procedures for estimating this parameter by considering 14 contingency tables that have appeared in the statistical and allied literature. The estimation of the standard error of the association parameter is also considered. 相似文献
480.
P. Angelopoulos 《Journal of applied statistics》2008,35(12):1399-1408
Robust parameter design, originally proposed by Taguchi [System of Experimental Design, Vols. I and II, UNIPUB, New York, 1987], is an offline production technique for reducing variation and improving a product's quality by using product arrays. However, the use of the product arrays results in an exorbitant number of runs. To overcome this drawback, several scientists proposed the use of combined arrays, where the control and noise factors are combined in a single array. In this paper, we use non-isomorphic orthogonal arrays as combined arrays, in order to identify a model that contains all the main effects (control and noise), their control-by-noise interactions and their control-by-control interactions with high efficiency. Some cases where the control-by-control-noise are of interest are also considered. 相似文献