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arXiv 1906.01908cs.LGmath.STstat.MLstat.TH
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随机删失下的经验风险最小化:理论与实践

Empirical Risk Minimization under Random Censorship: Theory and Practice

Télécom Paris, Institut Polytechnique de Paris(巴黎理工学院巴黎电信学院);BNP Paribas(法国巴黎银行)

Guillaume Ausset, Stéphan Clémençon, François Portier

摘要:

我们考虑经典的监督学习问题,其中一个连续的非负随机标签$Y$(即随机持续时间)是预测的基础上观察一个随机向量$X$值在$\mathbb{R}^d$与$d\geq 1$的回归规则与最小最小二乘误差。在各种应用中,从工业质量控制到公共卫生,例如通过信用风险分析,训练观察可以被正确删失,这意味着统计学习依赖于三元组$(X, \; \min\{Y,\; C\},\; δ)$的$n\geq 1$独立实现的集合,而不是$(X,Y)$的独立副本,其中$C$是具有未知分布的非负r. v.,建模审查,并且$δ=\mathbb{I}\{Y\leq C\}$指示持续时间是否被正确审查。由于在风险计算中忽略审查可能会明显导致严重低估目标持续时间并危及预测,因此我们建议考虑基于审查$C$的条件生存函数的Kaplan-Meier估计量(给定$X$,称为Kaplan-Meier风险)对真实风险进行插件估计,以执行经验风险最小化。它是建立,在温和的条件下,这种偏见/加权经验风险功能的极小化的学习率是为了$O_{\mathbb{P}}(\sqrt{\log(n)/n})$时,忽略固有的插件估计模型偏差问题,可以达到在没有审查。除了理论结果,数值实验,以说明相关的方法开发。

英文摘要:

We consider the classic supervised learning problem, where a continuous non-negative random label $Y$ (i.e. a random duration) is to be predicted based upon observing a random vector $X$ valued in $\mathbb{R}^d$ with $d\geq 1$ by means of a regression rule with minimum least square error. In various applications, ranging from industrial quality control to public health through credit risk analysis for instance, training observations can be right censored, meaning that, rather than on independent copies of $(X,Y)$, statistical learning relies on a collection of $n\geq 1$ independent realizations of the triplet $(X, \; \min\{Y,\; C\},\; δ)$, where $C$ is a nonnegative r.v. with unknown distribution, modeling censorship and $δ=\mathbb{I}\{Y\leq C\}$ indicates whether the duration is right censored or not. As ignoring censorship in the risk computation may clearly lead to a severe underestimation of the target duration and jeopardize prediction, we propose to consider a plug-in estimate of the true risk based on a Kaplan-Meier estimator of the conditional survival function of the censorship $C$ given $X$, referred to as Kaplan-Meier risk, in order to perform empirical risk minimization. It is established, under mild conditions, that the learning rate of minimizers of this biased/weighted empirical risk functional is of order $O_{\mathbb{P}}(\sqrt{\log(n)/n})$ when ignoring model bias issues inherent to plug-in estimation, as can be attained in absence of censorship. Beyond theoretical results, numerical experiments are presented in order to illustrate the relevance of the approach developed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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