A new graphical tool of outliers detection in regression models based on recursive estimation

使用 $\gamma$-散度的稳健贝叶斯图模型

Robust Bayesian graphical modeling using $γ$-divergence

本文提出一种基于 $\gamma$-散度的稳健贝叶斯高斯图模型推断方法，通过贝叶斯图形套索实现后验稳健性，并开发了加权贝叶斯自助法高效计算算法。

Graphical Condition for Identification in recursive SEM

The paper concerns the problem of predicting the effect of actions or interventions on a system from a combination of (i) statistical data on a set of observed variables, and (ii) qualitative causal knowledge encoded in the form of a directed acyclic graph (DAG). The DAG represents a set of linear equations called Structural Equations Model (SEM), whose coefficients are parameters representing direct causal effects. Reliable quantitative conclusions can only be obtained from the model if the causal effects are uniquely determined by the data. That is, if there exists a unique parametrization f…

The Influence Function of Graphical Lasso Estimators

The precision matrix that encodes conditional linear dependency relations among a set of variables forms an important object of interest in multivariate analysis. Sparse estimation procedures for precision matrices such as the graphical lasso (Glasso) gained popularity as they facilitate interpretability, thereby separating pairs of variables that are conditionally dependent from those that are independent (given all other variables). Glasso lacks, however, robustness to outliers. To overcome this problem, one typically applies a robust plug-in procedure where the Glasso is computed from a rob…

Outlier detection and trimmed estimation for general functional data

This article introduces trimmed estimators for the mean and covariance function of general functional data. The estimators are based on a new measure of outlyingness or data depth that is well defined on any metric space, although this paper focuses on Euclidean spaces. We compute the breakdown point of the estimators and show that the optimal breakdown point is attainable for the appropriate choice of tuning parameters. The small-sample behavior of the estimators is studied by simulation, and we show that they have better outlier-resistance properties than alternative estimators. This is conf…

Quantile Graphical Models: Bayesian Approaches

Graphical models are ubiquitous tools to describe the interdependence between variables measured simultaneously such as large-scale gene or protein expression data. Gaussian graphical models (GGMs) are well-established tools for probabilistic exploration of dependence structures using precision matrices and they are generated under a multivariate normal joint distribution. However, they suffer from several shortcomings since they are based on Gaussian distribution assumptions. In this article, we propose a Bayesian quantile based approach for sparse estimation of graphs. We demonstrate that th…

逐个案例和单元格鲁棒的多线性主成分分析

Casewise and Cellwise Robust Multilinear Principal Component Analysis

本文提出一种能同时处理案例和单元格异常值的鲁棒多线性主成分分析方法，通过迭代加权最小二乘算法解决缺失值问题，并通过图形工具检测异常值。