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arXiv 2404.09528stat.MEecon.EMstat.AP
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凸回归中的过拟合减少

Overfitting Reduction in Convex Regression

Zhiqiang Liao, Sheng Dai, Eunji Lim, Timo Kuosmanen

AI总结:

本文针对凸回归中随样本量增加而产生不一致估计和边界次梯度过大的过拟合问题,提出两种通过限制次梯度的新估计量,并从理论和芬兰电力企业应用上证明其能一致收敛并提升预测能力。

摘要:

凸回归是一种从数据集中估计凸函数的方法。该方法在运筹学、经济学、机器学习及许多其他领域发挥了重要作用。然而,经验观察表明,随着样本量增加,凸回归会产生不一致的凸函数估计,且在边界附近产生极大的次梯度。本文为这种过拟合行为提供了理论证据。为消除该行为,我们通过对凸函数的次梯度设定界限,提出了两种新的估计量。我们进一步证明,所提估计量能够减少过拟合,具体而言,随着样本量趋于无穷大,它们以概率一在定义域上一致收敛于潜在的真实凸函数,且其次梯度一致收敛于潜在函数的梯度。对芬兰电力配送企业的应用证实,所提方法在预测能力上优于现有方法。

英文摘要:

Convex regression is a method for estimating the convex function from a data set. This method has played an important role in operations research, economics, machine learning, and many other areas. However, it has been empirically observed that convex regression produces inconsistent estimates of convex functions and extremely large subgradients near the boundary as the sample size increases. In this paper, we provide theoretical evidence of this overfitting behavior. To eliminate this behavior, we propose two new estimators by placing a bound on the subgradients of the convex function. We further show that our proposed estimators can reduce overfitting by proving that they converge to the underlying true convex function and that their subgradients converge to the gradient of the underlying function, both uniformly over the domain with probability one as the sample size is increasing to infinity. An application to Finnish electricity distribution firms confirms the superior performance of the proposed methods in predictive power over the existing methods.

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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