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仿射估计的最优集结

Optimal aggregation of affine estimators
课程网址: http://videolectures.net/colt2011_salmon_optimal/  
主讲教师: Joseph Salmon
开课单位: 丹尼斯狄德罗大学
开课时间: 2011-08-02
课程语种: 英语
中文简介:
摘要在非参数回归模型中,我们考虑了一类具有异方差高斯噪声的仿射估计的组合问题。针对指数加权集,我们证明了一个PAC-Bayesian型不等式,该不等式在离散和连续的情况下都导致了明显的oracle不等式。该框架足够通用,可以涵盖各种方法的组合,如最小二乘回归、核脊回归、收缩估计值等,这些方法在统计逆问题的文献中使用。因此,我们证明了所提出的聚合提供了精确极小极大意义上的自适应估计,既不离散调整参数的范围,也不分裂观测集。我们还用数值方法说明了指数加权集的良好性能。
课程简介: We consider the problem of combining a (possibly uncountably infinite) set of affine estimators in non-parametric regression model with heteroscedastic Gaussian noise. Focusing on the exponentially weighted aggregate, we prove a PAC-Bayesian type inequality that leads to sharp oracle inequalities in discrete but also in continuous settings. The framework is general enough to cover the combinations of various procedures—such as the least square regression, the kernel ridge regression, the shrinkage estimators, etc.—used in the literature on statistical inverse problems. As a consequence, we show that the proposed aggregate provides an adaptive estimator in the exact minimax sense without neither discretizing the range of tuning parameters nor splitting the set of observations. We also illustrate numerically the good performance achieved by the exponentially weighted aggregate.
关 键 词: 非参数回归模型; 异方差高斯噪声; 仿射估计; 指数加权集; 最小二乘回归; 核脊回归; 收缩估计值
课程来源: 视频讲座网
最后编审: 2020-06-29:cxin
阅读次数: 62