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中间事件受删失时生存数据的局部似然分析AI 解读

AIDS Clinical Trials Group protocol 193A was a randomized trial designed to compare survival and progression-free survival among patients on different treatment regimens. A complicating feature of the analysis of progression-free survival is that different censoring mechanisms operated on progression and survival, which resulted in more complete information on survival. A simple analysis that uses the minimum of the times to progression and survival and the minimum of the…

用边际结构模型估计非随机处理的联合因果效应AI 解读

Even in the absence of unmeasured confounding factors or model misspecification, standard methods for estimating the causal effect of time-varying treatments on survival are biased when (a) there exists a time-dependent risk factor for survival that also predicts subsequent treatment, and (b) past treatment history predicts subsequent risk factor level. In contrast, methods based on marginal structural models (MSMs) can provide consistent estimates of causal effects when…

基于纵向标志物贝叶斯层级变点与混合模型的癌症风险筛查AI 解读

The standard approach to early detection of disease with a quantitative marker is to set a population-based fixed reference level for making further individual screening or referral decisions. For many types of disease, including prostate and ovarian cancer, additional information is contained in the subject-specific temporal behavior of the marker, which exhibits a characteristic alteration early in the course of the disease. In this article we derive a Bayesian approach to…

比较数字与模拟乳腺摄影的研究设计和分析方案AI 解读

Because randomized trials have shown a reduction in breast cancer mortality, analog mammography for the early detection of breast cancer has gained widespread use. Recently, several manufacturers have developed digital mammography, which promises great advantages in the storage and transmission of images. We were asked to design a study to compare the two types of mammography in terms of their performance for the early detection of breast cancer. A standard measure of…

单通道事件相关电位的随机小波包模型推断AI 解读

Event-related potentials (ERPs) are brain electrical potentials associated with sensory and cognitive processing. ERP researchers typically wish to separate a recorded time series into functionally distinct component waveforms, and to estimate the effects of experimental conditions on each component. We present an integrated statistical approach to the decomposition of single-channel ERPs and to inference concerning the component waveforms and the effects of experimental…

曲线的贝叶斯小波回归及其光谱校准应用AI 解读

Motivated by calibration problems in near-infrared (NIR) spectroscopy, we consider the linear regression setting in which the many predictor variables arise from sampling an essentially continuous curve at equally spaced points and there may be multiple predictands. We tackle this regression problem by calculating the wavelet transforms of the discretized curves, then applying a Bayesian variable selection method using mixture priors to the multivariate regression of…

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This article reviews the principle of minimum description length (MDL) for problems of model selection. By viewing statistical modeling as a means of generating descriptions of observed data, the MDL framework discriminates between competing models based on the complexity of each description. This approach began with Kolmogorov's theory of algorithmic complexity, matured in the literature on information theory, and has recently received renewed attention within the…

随机删失与序约束下的密度估计AI 解读

Do a random censorship and/or order restrictions (e.g., nonnegativity, monotonicity, convexity) affect estimation of a smooth density under mean integrated squared error (MISE)? Under mild assumptions, the known asymptotic results, which are concerned only with rates, answer “no.” This answer, especially for censored data, contradicts practical experience and statistical intuition. So what can be said about constants of MISE convergence? It is shown that asymptotically (a)…

点过程的半参数变换模型AI 解读

In this article, we propose a family of semiparametric transformation models for point processes with positive jumps of arbitrary sizes. These models offer great flexibilities in formulating the effects of covariates on the mean function of the point process while leaving the stochastic structure completely unspecified. We develop a class of estimating equations for the baseline mean function and the vector-valued regression parameter based on censored point processes and…

通过混合实现自适应回归AI 解读

Adaptation over different procedures is of practical importance. Different procedures perform well under different conditions. In many practical situations, it is rather hard to assess which conditions are (approximately) satisfied so as to identify the best procedure for the data at hand. Thus automatic adaptation over various scenarios is desirable. A practically feasible method, named adaptive regression by mixing (ARM), is proposed to convexly combine general candidate…

音乐声音信号的局部谐波估计AI 解读

Statistical modeling and analysis have been applied to different music-related fields, including sound synthesis and analysis. Sound can be represented as a real-valued function of time. This function can be sampled at a sufficiently small rate such that the resulting discrete version is a good approximation of the continuous version, thus enabling the study of musical sounds as a discrete time series, an entity for which many statistical techniques are available. Physical…

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无处理状态下的稳定性AI 解读

When subjects are measured twice, once at each of two symmetrical locations or times, stability of responses in the absence of treatment within subjects, together with comparability of untreated responses between subjects, is often viewed as supporting a conclusion that differences between treated and control responses reflect effects actually caused by the treatment. The degree to which this intuitive argument is formally correct is explored in several related models: a…

参数模型对非参数备择的贝叶斯与条件频率学派检验AI 解读

Testing the fit of data to a parametric model can be done by embedding the parametric model in a nonparametric alternative and computing the Bayes factor of the parametric model to the nonparametric alternative. Doing so by specifying the nonparametric alternative via a Polya tree process is particularly attractive, from both theoretical and methodological perspectives. Among the benefits is a degree of computational simplicity that even allows for robustness analyses to be…

纵向数据的半参数与非参数回归分析AI 解读

This article deals with the regression analysis of repeated measurements taken at irregular and possibly subject-specific time points. The proposed semiparametric and nonparametric models postulate that the marginal distribution for the repeatedly measured response variable Y at time t is related to the vector of possibly time-varying covariates X through the equations E{Y(t)|| X(t} = α0(t) + β′0X(t) and E{Y(t)||X(t)} = α0(t)+ β′0(t)X(t), where α0(t) is an arbitrary function…

存在阻断与协同作用的群组检测AI 解读

Discovery and development of a new drug can cost hundreds of millions of dollars. Pharmaceutical companies have used group testing methodology routinely as one of the efficient high throughput screening techniques to search for “lead” compounds among collections of hundreds of thousands of chemical compounds. The lead compounds can be modified to produce new and effective molecules, which eventually may lead to new drugs. This article develops models and estimation…

点源附近疾病风险的贝叶斯建模AI 解读

Recently there has been increased interest, from both the media and the public, in the question, “Is there an excess of disease risk close to a prespecified point source?” To address this question, routinely available public health data may be analyzed. In the United Kingdom, as in many countries, health data and the associated population data that are required for comparison, are available as aggregated counts. In this article we propose to analyze such data using a…

考古磁测调查数据的贝叶斯分析AI 解读

A model is presented for the interpretation of magnetometer data in terms of archeological features beneath the ground. It describes the detector's response to the assemblage of buried features, incorporating both a spread function and a statistical error process as well as appropriate prior beliefs about the nature of archeological features. The problem is to estimate the magnetic susceptibility of the buried features at each horizontal location. A Monte Carlo Markov chain…

拟合 Kent 分布混合模型以辅助识别岩体节理组AI 解读

When examining a rock mass, joint sets and their orientations can play a significant role with regard to how the rock mass will behave. To identify joint sets present in the rock mass, the orientation of individual fracture planes can be measured on exposed rock faces and the resulting data can be examined for heterogeneity. In this article, the expectation–maximization algorithm is used to fit mixtures of Kent component distributions to the fracture data to aid in the…

利用混合模型迭代开展自动记录链接AI 解读

The goal of record linkage is to link quickly and accurately records that correspond to the same person or entity. Whereas certain patterns of agreements and disagreements on variables are more likely among records pertaining to a single person than among records for different people, the observed patterns for pairs of records can be viewed as arising from a mixture of matches and nonmatches. Mixture model estimates can be used to partition record pairs into two or more…