自适应选择扰动,提升模型解释的可靠性和稳定性。
Informative Perturbation Selection for Uncertainty-Aware Post-hoc Explanations
- 通过信息论优化扰动选择,动态聚焦最有价值的局部样本。
- 实验显示解释结果更稳定,扰动质量更高,重复性显著改善。
- 适合需要可信解释的高风险场景,如医疗、金融决策支持。
由于广泛部署的黑箱机器学习模型引发信任与伦理问题,亟需可靠的模型解释。后处理模型无关解释方法通过构建逼近目标样本局部行为的代理模型来应对这一挑战。在无模型参数与训练数据的情况下,需通过生成目标样本邻域的扰动输入及其预测来构造局部邻域。本文提出 exttt{EAGLE} 框架,将扰动选择建模为信息论驱动的主动学习问题。通过自适应采样能最大化期望信息增益的扰动, exttt{EAGLE} 高效学习线性可解释代理模型,并输出特征重要性及不确定性估计。理论上,累积信息增益呈 $/mathcal{O}(d /log t)$ 量级,样本复杂度随特征维度 $d$ 线性增长,随置信参数 $1/δ$ 对数增长。在表格和图像数据集上的实验证实了理论结果,表明 exttt{EAGLE} 在不同运行间具有更高的解释可重现性,邻域稳定性更强,且优于 Tilia、US-LIME、GLIME 与 BayesLIME 等先进基线。
原文摘要 · Abstract (English)
Trust and ethical concerns due to the widespread deployment of opaque machine learning (ML) models motivating the need for reliable model explanations. Post-hoc model-agnostic explanation methods addresses this challenge by learning a surrogate model that approximates the behavior of the deployed black-box ML model in the locality of a sample of interest. In post-hoc scenarios, neither the underlying model parameters nor the training are available, and hence, this local neighborhood must be constructed by generating perturbed inputs in the neighborhood of the sample of interest, and its corresponding model predictions. We propose \emph{Expected Active Gain for Local Explanations} (\texttt{EAGLE}), a post-hoc model-agnostic explanation framework that formulates perturbation selection as an information-theoretic active learning problem. By adaptively sampling perturbations that maximize the expected information gain, \texttt{EAGLE} efficiently learns a linear surrogate explainable model while producing feature importance scores along with the uncertainty/confidence estimates. Theoretically, we establish that cumulative information gain scales as $\mathcal{O}(d \log t)$, where $d$ is the feature dimension and $t$ represents the number of samples, and that the sample complexity grows linearly with $d$ and logarithmically with the confidence parameter $1/δ$. Empirical results on tabular and image datasets corroborate our theoretical findings and demonstrate that \texttt{EAGLE} improves explanation reproducibility across runs, achieves higher neighborhood stability, and improves perturbation sample quality as compared to state-of-the-art baselines such as Tilia, US-LIME, GLIME and BayesLIME.
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