arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2205.00403cs.LGstat.ML
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通过距离感知改善单模型深度不确定性的简单方法

A Simple Approach to Improve Single-Model Deep Uncertainty via Distance-Awareness

Google Research(谷歌研究院);Waymo(Waymo公司)

Jeremiah Zhe Liu, Shreyas Padhy, Jie Ren, Zi Lin, Yeming Wen, Ghassen Jerfel, Zack Nado, Jasper Snoek, Dustin Tran, Balaji Lakshminarayanan

摘要:

准确的不确定性量化是深度学习中的一个主要挑战,因为神经网络可能会产生过度自信的错误,并将高置信度预测分配给分布外(OOD)输入。在深度学习中估计预测不确定性的最流行方法是组合来自多个神经网络的预测的方法,例如贝叶斯神经网络(BNN)和深度集成。然而,由于高存储器和计算成本,它们在实时工业规模应用中的实用性受到限制。此外,集成和BNN不一定解决底层成员网络的所有问题。在这项工作中,我们研究了原则性的方法,以提高一个单一的网络的不确定性,基于一个单一的,确定性的表示。通过将不确定性量化形式化为极大极小学习问题,我们首先识别距离感知,即,模型量化测试示例与训练数据的距离的能力,作为DNN实现高质量的必要条件(即,最小最大最优)不确定性估计。然后,我们提出了频谱归一化神经高斯过程(SNGP),这是一种简单的方法,可以通过两个简单的变化来提高现代DNN的距离感知能力:(1)将频谱归一化应用于隐藏权重,以加强表示中的双Lipschitz平滑性,以及(2)用高斯过程层替换最后一个输出层。在一系列视觉和语言理解基准测试中,SNGP在预测、校准和域外检测方面优于其他单模型方法。此外,SNGP还为深度集成和数据增强等流行技术提供了互补优势,使其成为概率深度学习的简单且可扩展的构建块。代码在www.example.com上开源

英文摘要:

Accurate uncertainty quantification is a major challenge in deep learning, as neural networks can make overconfident errors and assign high confidence predictions to out-of-distribution (OOD) inputs. The most popular approaches to estimate predictive uncertainty in deep learning are methods that combine predictions from multiple neural networks, such as Bayesian neural networks (BNNs) and deep ensembles. However their practicality in real-time, industrial-scale applications are limited due to the high memory and computational cost. Furthermore, ensembles and BNNs do not necessarily fix all the issues with the underlying member networks. In this work, we study principled approaches to improve uncertainty property of a single network, based on a single, deterministic representation. By formalizing the uncertainty quantification as a minimax learning problem, we first identify distance awareness, i.e., the model's ability to quantify the distance of a testing example from the training data, as a necessary condition for a DNN to achieve high-quality (i.e., minimax optimal) uncertainty estimation. We then propose Spectral-normalized Neural Gaussian Process (SNGP), a simple method that improves the distance-awareness ability of modern DNNs with two simple changes: (1) applying spectral normalization to hidden weights to enforce bi-Lipschitz smoothness in representations and (2) replacing the last output layer with a Gaussian process layer. On a suite of vision and language understanding benchmarks, SNGP outperforms other single-model approaches in prediction, calibration and out-of-domain detection. Furthermore, SNGP provides complementary benefits to popular techniques such as deep ensembles and data augmentation, making it a simple and scalable building block for probabilistic deep learning. Code is open-sourced at https://github.com/google/uncertainty-baselines

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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