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利用傅里叶方法进行离散拉普拉斯平滑AI 解读

An approach to multidimensional smoothing is introduced that is based on a penalized likelihood with a modified discretized Laplacian penalty term. The choice of penalty simplifies computational difficulties associated with standard multidimensional Laplacian smoothing methods yet without compromising mean squared error characteristics, at least on the interior of the region of interest. For linear smoothing in hyper-rectangular domains, which has wide application in image…

临床神经解剖学中重复空间点模式的方差分析AI 解读

Our application concerns the analysis of the spatial distributions of pyramidal neurons in the cingulate cortex of human subjects in three diagnostic groupings. Our purpose is to develop and apply several methods for the analysis of replicated spatial point patterns to identify anatomical differences between normal, schizoaffective, and schizophrenic persons at the time of death. We begin with a scaled Poisson analysis that uncovers significant differences between the groups…

暂定死亡率序列的调整：含结构化测量误差的动态线性模型AI 解读

The authors "consider the problem of adjusting provisional time series using a bivariate structural model with correlated measurement errors. Maximum likelihood estimators and a minimum mean squared error adjustment procedure are derived for a provisional and final series containing common trend and seasonal components. The model also includes measurement errors common to both series and errors that are specific to the provisional series. [The authors] illustrate the…

从历史数据估计火山活动的二阶参数AI 解读

To study patterns of volcanicity it is important to use historical data. These data are, however, frequently incomplete. We develop a nonparametric procedure for estimating second-order parameters of the point process of eruption starts from a catalog. This method requires an assumption of underlying stationarity, of smoothness of the probability of recording an eruption as a function of time, and of independence of this probability from the history of the process. We…

多抽样框调查中迭代比例估计的效率AI 解读

Multiple frame surveys involve the combination of samples selected from separate sampling frames. A topical example is a dual-frame survey that combines a sample of households interviewed by telephone with a sample drawn from a frame including nontelephone households. Various estimators of population totals and means have been proposed for multiple frame surveys. In particular Bankier proposed the application of raking ratio estimation and compared its performance to…

带切换的动态线性模型AI 解读

The problem of modeling change in a vector time series is studied using a dynamic linear model with measurement matrices that switch according to a time-varying independent random process. We derive filtered estimators for the usual state vectors and also for the state occupancy probabilities of the underlying nonstationary measurement process. A maximum likelihood estimation procedure is given that uses a pseudo-expectation-maximization algorithm in the initial stages and…

重复测量数据中变化速率的序贯比较AI 解读

There are many clinical trials in which the patients enter sequentially, and a response variable is measured repeatedly over time for each patient. A group sequential procedure is proposed for comparing the rates of change between two treatment groups. Some existing procedures for testing the equality of means between two treatment groups with repeated measurements data, such as those proposed by Armitage, Stratton, and Worthington and by Geary, can be interpreted as special…

基于近似重复观测的失拟检验：小样本刻画AI 解读

Several ad hoc tests based on near replicates have been proposed for testing lack of fit in regression analysis. Christensen characterized lack of fit as existing between clusters of near replicates, within clusters, or as a combination of these pure types. Of these, the between-cluster variety is the type commonly associated with the idea of lack of fit. Christensen examined a test that was new to the normal theory regression literature and established uniformly most…

超额质量估计与多峰性检验AI 解读

We propose and study a method for analyzing the modality of a distribution. The method is based on the excess mass functional. This functional measures excessive empirical mass in comparison with multiples of uniform distribution. By the excess mass approach we separate the investigation about the number of modes from questions concerning their location. For distributions on the line, the excess mass functional can be estimated at a square-root rate. The asymptotic behavior…

修剪均值置换分布的高效计算AI 解读

The permutation distribution of the trimmed mean in matched-pairs designs is studied. This statistic is important since it is robust to both outliers and distributional assumptions. A polynomial-time algorithm for this inherently exponential-time problem is presented. The characteristic function of the distribution provides both the basis for the algorithm and a vehicle for calculating the asymptotic permutation distribution.

迭代重加权最小二乘估计量的影响函数AI 解读

The iteratively reweighted least squares algorithm is routinely employed to evaluate robust regression estimates. The importance of beginning the algorithm with a robust estimator of the unknown parameters is often stressed. The precise influence of the initial estimator on subsequent iterates or the limit of such estimators, however, does not seem to have been calculated previously. Because robust regression involves the downweighting of specific points having large…

样条平滑中交叉验证平滑参数的影响诊断AI 解读

This article addresses the problem of influence in estimating the smoothing parameter when fitting a univariate smoothing spline. Diagnostics are presented that can identify observations that locally influence the choice of smoothing parameter by generalized cross-validation, either through their case weights or observed responses. Generalized cross-validation and the diagnostic methods are given a frequency interpretation and illustrated with examples.

大量观测下核平滑条件分位数的计算AI 解读

Quantiles of a variable Y conditional on another variable X, when plotted against X, can be a useful descriptive tool. These plots give a quick impression of the functional form of the relation between X and the location, spread, and shape of the conditional distribution of Y. If several Y are observed for each X, then sample quantiles could be calculated for each X. The resulting quantile plot may be quite noisy, however, and smoothing across X may be desired. This article…

比较实验与小区域估计中的贝叶斯及非贝叶斯程序：计算、频率学性质与联系AI 解读

The estimation of a treatment contrast from experimental data and the estimation of a small-area mean are special cases of the prediction of the realization of a linear combination of fixed and random effects in a possibly unbalanced two-part mixed linear model. In this article a Bayesian approach to point and interval prediction is presented and its computational requirements are examined. Differences between the Bayesian approach and the traditional (classical) approach…

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稳健估计与检验AI 解读

The Field of Statistics. Estimating Scale----Finite Sample Results. Estimating Scale----Asymptotic Results. Location--Dispersion Estimation. Testing for a Location Parameter. The Two--Sample Problem. Regression. Appendices. References. Author Index. Subject Index.

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带切换机制的动态线性模型AI 解读

The problem of modeling change in a vector time series is studied using a dynamic linear model with measurement matrices that switch according to a time-varying independent random process. We derive filtered estimators for the usual state vectors and also for the state occupancy probabilities of the underlying nonstationary measurement process. A maximum likelihood estimation procedure is given that uses a pseudo-expectation-maximization algorithm in the initial stages and…

相关矩阵中特定主成分的检验AI 解读

In the application of principal components analysis it is common to replace an observed sample principal component vector by another vector closely resembling the sample vector but which is easier to use or interpret. A useful test of hypothesis in this case is one that specifies the true ith principal component. In this article we obtain an asymptotically chi-squared procedure suitable for testing such a hypothesis when the principal components analysis is performed on a…

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利用历史数据估计火山活动的二阶参数AI 解读

To study patterns of volcanicity it is important to use historical data. These data are, however, frequently incomplete. We develop a nonparametric procedure for estimating second-order parameters of the point process of eruption starts from a catalog. This method requires an assumption of underlying stationarity, of smoothness of the probability of recording an eruption as a function of time, and of independence of this probability from the history of the process. We…