论文标题

通过阻滞影响功能,复发性神经网络中常见的不确定性

Frequentist Uncertainty in Recurrent Neural Networks via Blockwise Influence Functions

论文作者

Alaa, Ahmed M., van der Schaar, Mihaela

论文摘要

复发性神经网络(RNN)有助于对顺序和时间序列数据进行建模。但是,当使用RNN为决策提供信息时,预测本身还不够。我们还需要估计预测不确定性。 RNN中不确定性定量的现有方法主要基于贝叶斯方法。这些是计算上的过敏性,需要对RNN架构和培训进行重大改变。利用古典折刀重新采样的想法,我们开发了一种常见的选择:(a)不会干扰模型培训或损害其准确性,(b)适用于任何RNN架构,(c)在估计的不确定性间隔上提供了理论覆盖的保证。我们的方法从RNN输出的(折刀)采样分布的变异性中得出了预测性不确定性,该分布通过反复删除(时间相关)训练数据的块来估计,并收集对其余数据重新培训的RNN的预测。为了避免详尽的重新训练,我们利用影响功能来估计删除训练数据块对学习的RNN参数的影响。使用来自重症监护设置的数据,我们证明了连续决策中不确定性定量的实用性。

Recurrent neural networks (RNNs) are instrumental in modelling sequential and time-series data. Yet, when using RNNs to inform decision-making, predictions by themselves are not sufficient; we also need estimates of predictive uncertainty. Existing approaches for uncertainty quantification in RNNs are based predominantly on Bayesian methods; these are computationally prohibitive, and require major alterations to the RNN architecture and training. Capitalizing on ideas from classical jackknife resampling, we develop a frequentist alternative that: (a) does not interfere with model training or compromise its accuracy, (b) applies to any RNN architecture, and (c) provides theoretical coverage guarantees on the estimated uncertainty intervals. Our method derives predictive uncertainty from the variability of the (jackknife) sampling distribution of the RNN outputs, which is estimated by repeatedly deleting blocks of (temporally-correlated) training data, and collecting the predictions of the RNN re-trained on the remaining data. To avoid exhaustive re-training, we utilize influence functions to estimate the effect of removing training data blocks on the learned RNN parameters. Using data from a critical care setting, we demonstrate the utility of uncertainty quantification in sequential decision-making.

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