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111.
This paper considers estimation and prediction in the Aalen additive hazards model in the case where the covariate vector
is high-dimensional such as gene expression measurements. Some form of dimension reduction of the covariate space is needed
to obtain useful statistical analyses. We study the partial least squares regression method. It turns out that it is naturally
adapted to this setting via the so-called Krylov sequence. The resulting PLS estimator is shown to be consistent provided
that the number of terms included is taken to be equal to the number of relevant components in the regression model. A standard
PLS algorithm can also be constructed, but it turns out that the resulting predictor can only be related to the original covariates
via time-dependent coefficients. The methods are applied to a breast cancer data set with gene expression recordings and to
the well known primary biliary cirrhosis clinical data. 相似文献
112.
谷满意 《河北工程大学学报(社会科学版)》2009,26(3):71-74,87
新时期网络参政对中国民主政治发展促进作用将更加明显,是有中国特色民主政治发展的重要内容之一。网络参政的作用已经引起了党和国家领导人的重视,地方党和政府的负责人也逐渐注意到网络参政的实际意义,其作用主要体现在:促进参与式民主的发展;促进传统集权等级制权力结构的转换;促进社会平等;促进政治、政府公开的发展;促进选民与人大代表的沟通;促进公民政治社会化的加强。网络参政还是把双刃剑,应该加强规范和管理。 相似文献
113.
Most studies of quality improvement deal with ordered categorical data from industrial experiments. Accounting for the ordering of such data plays an important role in effectively determining the optimal factor level of combination. This paper utilizes the correspondence analysis to develop a procedure to improve the ordered categorical response in a multifactor state system based on Taguchi's statistic. Users may find the proposed procedure in this paper to be attractive because we suggest a simple and also popular statistical tool for graphically identifying the really important factors and determining the levels to improve process quality. A case study for optimizing the polysilicon deposition process in a very large-scale integrated circuit is provided to demonstrate the effectiveness of the proposed procedure. 相似文献
114.
Huber's estimator has had a long lasting impact, particularly on robust statistics. It is well known that under certain conditions, Huber's estimator is asymptotically minimax. A moderate generalization in rederiving Huber's estimator shows that Huber's estimator is not the only choice. We develop an alternative asymptotic minimax estimator and name it regression with stochastically bounded noise (RSBN). Simulations demonstrate that RSBN is slightly better in performance, although it is unclear how to justify such an improvement theoretically. We propose two numerical solutions: an iterative numerical solution, which is extremely easy to implement and is based on the proximal point method; and a solution by applying state-of-the-art nonlinear optimization software packages, e.g., SNOPT. Contribution: the generalization of the variational approach is interesting and should be useful in deriving other asymptotic minimax estimators in other problems. 相似文献
115.
It is often the case that high-dimensional data consist of only a few informative components. Standard statistical modeling and estimation in such a situation is prone to inaccuracies due to overfitting, unless regularization methods are practiced. In the context of classification, we propose a class of regularization methods through shrinkage estimators. The shrinkage is based on variable selection coupled with conditional maximum likelihood. Using Stein's unbiased estimator of the risk, we derive an estimator for the optimal shrinkage method within a certain class. A comparison of the optimal shrinkage methods in a classification context, with the optimal shrinkage method when estimating a mean vector under a squared loss, is given. The latter problem is extensively studied, but it seems that the results of those studies are not completely relevant for classification. We demonstrate and examine our method on simulated data and compare it to feature annealed independence rule and Fisher's rule. 相似文献
116.
大凡读过高中的人,都知道佛莱铭左手和右手定则,这种左、右定则很容易记错,有时要将手扭歪才能判定其方向,很难运用.为了方便学生记忆及方便判定方向,设法设计出一种新的右手定则,可以同时判定磁场对电流的作用力及磁场中导线所产生的感生电流的方向,显然这种右手定则是一个创新. 相似文献
117.
Gary Neil Marks 《Social indicators research》2008,85(2):293-309
Since the early 1970s the importance of mothers’ socioeconomic characteristics on their children’s educational and occupational
attainment has been acknowledged. However, it is not clear if fathers’ characteristics have a stronger influence because men
usually have stronger attachments to the labour market, or alternatively mothers’ characteristics are more important because
of their greater role in children’s socialization. This study addresses this question by comparing the influence of father’s
and mother’s education and occupation on student performance in literacy and numeracy using data from 30 countries. The impact
of mother’s education is usually greater or comparable to that of father’s education. In contrast, substantially stronger
effects for mother’s occupational status compared to father’s were rare. In most countries the impact of mother’s socioeconomic
characteristics (education plus occupation) on student performance is comparable to that for father’s. Of the four indicators
of socioeconomic background, father’s occupational status and mother’s educational attainment tend to have stronger effects,
although many countries do not conform to this pattern. There are indications that the relative importance of mother’s characteristics
have increased over time.
相似文献
Gary Neil MarksEmail: |
118.
由于多种原因。使得东乡族女童教育面临着严峻挑战。本文在分析了东乡族女童教育的现状及其形成原因的基础上.尝试性地探讨了东乡族女童教育的发展路向。 相似文献
119.
邹志远 《延边大学东疆学刊》2001,18(2):70-71
“体”一词 ,是李奎报诗论最为重要的审美范畴。“体”这个概念在李奎报诗论中有两种含义 :一者 ,指“诗作法” ;二者 ,指“艺术风格”。李奎报的诗歌审美评价 ,对中国当代文学吸收外国文学遗产的过程中具有借鉴意义 相似文献
120.
Jennifer J. Driscoll 《Child Abuse Review》2009,18(5):333-345
Media coverage of the death of Baby P revived national concerns about the standard of child safeguarding practice in England following the implementation of widespread structural changes in response to the Victoria Climbié Inquiry chaired by Lord Laming in 2003. This paper discusses the recommendations of Lord Laming's recent Progress Report. It questions whether the scale of the challenge in improving child protection is fully recognised and considers briefly the culture of social care in the UK and the barriers to effective reform. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献