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arXiv 2103.13233stat.ME
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降维森林:使用结构化随机森林的局部变量重要性

Dimension Reduction Forests: Local Variable Importance using Structured Random Forests

Joshua Daniel Loyal, Ruoqing Zhu, Yifan Cui, Xin Zhang

摘要:

随机森林是最流行的机器学习方法之一,由于其准确性和变量重要性评估。然而,随机森林仅提供全局意义上的可变重要性。由于个性化医疗、决策和生物信息学的应用,越来越需要在地方一级进行这种评估。我们提出了一个新的非参数估计,对灵活的随机森林核与当地充分的降维,以适应回归函数的局部结构。这允许我们在每个预测点估计有意义的方向局部变量重要性度量。我们开发了一个计算效率的拟合过程,并提供了充分条件的分裂方向的恢复。我们证明了我们提出的估计在模拟和真实回归问题上的竞争方法的显着精度增益。最后,我们将所提出的方法应用于在中国北京收集的季节性颗粒物浓度数据,产生有意义的本地重要性措施。这里介绍的方法可以在drforest Python包中找到。

英文摘要:

Random forests are one of the most popular machine learning methods due to their accuracy and variable importance assessment. However, random forests only provide variable importance in a global sense. There is an increasing need for such assessments at a local level, motivated by applications in personalized medicine, policy-making, and bioinformatics. We propose a new nonparametric estimator that pairs the flexible random forest kernel with local sufficient dimension reduction to adapt to a regression function's local structure. This allows us to estimate a meaningful directional local variable importance measure at each prediction point. We develop a computationally efficient fitting procedure and provide sufficient conditions for the recovery of the splitting directions. We demonstrate significant accuracy gains of our proposed estimator over competing methods on simulated and real regression problems. Finally, we apply the proposed method to seasonal particulate matter concentration data collected in Beijing, China, which yields meaningful local importance measures. The methods presented here are available in the drforest Python package.

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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