提供准确估计其不确定性的计算模型对于与医疗保健环境中的决策相关的风险管理至关重要。尤其如此,因为许多最先进的系统都是使用已自动标记(自我监督模式)并倾向于过度标记的数据训练的。在这项工作中,我们研究了从放射学报告中应用于观察检测问题的一系列当前最新预测模型的不确定性估计质量。对于医疗保健领域中的自然语言处理,此问题仍在研究。我们证明,高斯工艺(GPS)在量化3个不确定性标签的风险方面具有卓越的性能,基于负对数预测概率(NLPP)评估度量和平均最大预测置信度(MMPCL),同时保留强大的预测性能。
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数据质量的系统量化对于一致的模型性能至关重要。先前的工作集中在分发数据上。取而代之的是,我们解决了一个研究了一个研究的且同样重要的问题,即表征不协调的区域(ID)数据,这可能是由特征空间异质性引起的。为此,我们提出了使用数据套件的范式转移:一个以数据为中心的AI框架来识别这些区域,而与特定于任务的模型无关。数据套件利用Copula建模,表示学习和共形预测,以基于一组培训实例来构建功能置信区间估计器。这些估计器可用于评估有关培训集的测试实例的一致性,以回答两个实际有用的问题:(1)通过培训培训实例培训的模型可以可靠地预测哪些测试实例? (2)我们可以确定功能空间的不协调区域,以便数据所有者了解数据的局限性还是指导未来数据收集?我们从经验上验证了数据套件的性能和覆盖范围保证,并在跨站点的医疗数据,有偏见的数据以及具有概念漂移的数据上证明,数据套件最能确定下游模型可能是可靠的ID区域(与所述模型无关)。我们还说明了这些确定的区域如何为数据集提供见解并突出其局限性。
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In the past years, deep learning has seen an increase of usage in the domain of histopathological applications. However, while these approaches have shown great potential, in high-risk environments deep learning models need to be able to judge their own uncertainty and be able to reject inputs when there is a significant chance of misclassification. In this work, we conduct a rigorous evaluation of the most commonly used uncertainty and robustness methods for the classification of Whole-Slide-Images under domain shift using the H\&E stained Camelyon17 breast cancer dataset. Although it is known that histopathological data can be subject to strong domain shift and label noise, to our knowledge this is the first work that compares the most common methods for uncertainty estimation under these aspects. In our experiments, we compare Stochastic Variational Inference, Monte-Carlo Dropout, Deep Ensembles, Test-Time Data Augmentation as well as combinations thereof. We observe that ensembles of methods generally lead to higher accuracies and better calibration and that Test-Time Data Augmentation can be a promising alternative when choosing an appropriate set of augmentations. Across methods, a rejection of the most uncertain tiles leads to a significant increase in classification accuracy on both in-distribution as well as out-of-distribution data. Furthermore, we conduct experiments comparing these methods under varying conditions of label noise. We observe that the border regions of the Camelyon17 dataset are subject to label noise and evaluate the robustness of the included methods against different noise levels. Lastly, we publish our code framework to facilitate further research on uncertainty estimation on histopathological data.
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最近,深度学习中的不确定性估计已成为提高安全至关重要应用的可靠性和鲁棒性的关键领域。尽管有许多提出的方法要么关注距离感知模型的不确定性,要么是分布式检测的不确定性,要么是针对分布校准的输入依赖性标签不确定性,但这两种类型的不确定性通常都是必要的。在这项工作中,我们提出了用于共同建模模型和数据不确定性的HETSNGP方法。我们表明,我们提出的模型在这两种类型的不确定性之间提供了有利的组合,因此在包括CIFAR-100C,ImagEnet-C和Imagenet-A在内的一些具有挑战性的分发数据集上优于基线方法。此外,我们提出了HETSNGP Ensemble,这是我们方法的结合版本,该版本还对网络参数的不确定性进行建模,并优于其他集合基线。
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不确定性估计(UE)技术 - 例如高斯过程(GP),贝叶斯神经网络(BNN),蒙特卡罗辍学(MCDropout) - 旨在通过为每个分配估计的不确定性值来提高机器学习模型的可解释性他们的预测输出。然而,由于过高的不确定性估计可以在实践中具有致命的后果,因此本文分析了上述技术。首先,我们表明GP方法始终会产生高不确定性估计(OOD)数据。其次,我们在2D玩具示例中显示了BNN和MCDRopout在OOD样品上没有提供高不确定性估计。最后,我们凭经验展示了这种BNNS和MCDRopout的陷阱也在现实世界数据集中持有。我们的见解(i)提高了对深度学习中目前流行的UE方法更加谨慎使用的认识,(ii)鼓励开发UE方法,这些方法近似于基于GP的方法 - 而不是BNN和MCDROPOUT,以及我们的经验设置可用于验证任何其他UE方法的ood性能。源代码在https://github.com/epfml/unctemationsiapity-娱乐中获得。
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贝叶斯神经网络中近似后期的估计不确定性易于进行错误校准,这导致关键任务中的预测过高,这些任务的预测明显不对称或损失明显。在这里,我们通过在深度学习中校准不确定性后的模型上最大化预期效用,扩展了对损失的贝叶斯框架的近似推断,以最大程度地提高预期效用。此外,我们表明,通过损失不确定性告知的决策可以比直接替代方案更大程度地提高诊断性能。我们提出最大的不确定性校准误差(MUCE)作为测量校准置信度的指标,除了其预测外,特别是对于高风险应用程序,其目标是最大程度地减少误差和估计不确定性之间的最坏情况偏差。在实验中,我们通过将Wasserstein距离作为预测的准确性来显示预测误差与估计不确定性之间的相关性。我们评估了我们从X射线图像中检测COVID-19的方法的有效性。实验结果表明,我们的方法大大减少了错误校准,而不会影响模型的准确性并提高基于计算机的诊断的可靠性。
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人工智能的最新趋势是将验证的模型用于语言和视觉任务,这些模型已经实现了非凡的表现,但也令人困惑。因此,以各种方式探索这些模型的能力对该领域至关重要。在本文中,我们探讨了模型的可靠性,在其中我们将可靠的模型定义为一个不仅可以实现强大的预测性能,而且在许多涉及不确定性(例如选择性预测,开放式设置识别)的决策任务上,在许多决策任务上表现出色,而且表现良好。强大的概括(例如,准确性和适当的评分规则,例如在分布数据集中和分发数据集上的对数可能性)和适应性(例如,主动学习,几乎没有射击不确定性)。我们设计了40个数据集的10种任务类型,以评估视觉和语言域上可靠性的不同方面。为了提高可靠性,我们分别开发了VIT-PLEX和T5-PLEX,分别针对视觉和语言方式扩展了大型模型。 PLEX极大地改善了跨可靠性任务的最先进,并简化了传统协议,因为它可以改善开箱即用的性能,并且不需要设计分数或为每个任务调整模型。我们演示了高达1B参数的模型尺寸的缩放效果,并预处理数据集大小最多4B示例。我们还展示了PLEX在具有挑战性的任务上的功能,包括零射门的开放式识别,主动学习和对话语言理解中的不确定性。
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Deep learning models that leverage large datasets are often the state of the art for modelling molecular properties. When the datasets are smaller (< 2000 molecules), it is not clear that deep learning approaches are the right modelling tool. In this work we perform an extensive study of the calibration and generalizability of probabilistic machine learning models on small chemical datasets. Using different molecular representations and models, we analyse the quality of their predictions and uncertainties in a variety of tasks (binary, regression) and datasets. We also introduce two simulated experiments that evaluate their performance: (1) Bayesian optimization guided molecular design, (2) inference on out-of-distribution data via ablated cluster splits. We offer practical insights into model and feature choice for modelling small chemical datasets, a common scenario in new chemical experiments. We have packaged our analysis into the DIONYSUS repository, which is open sourced to aid in reproducibility and extension to new datasets.
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标记数据可以是昂贵的任务,因为它通常由域专家手动执行。对于深度学习而言,这是繁琐的,因为它取决于大型标记的数据集。主动学习(AL)是一种范式,旨在通过仅使用二手车型认为最具信息丰富的数据来减少标签努力。在文本分类设置中,在AL上完成了很少的研究,旁边没有涉及最近的最先进的自然语言处理(NLP)模型。在这里,我们介绍了一个实证研究,可以将基于不确定性的基于不确定性的算法与Bert $ _ {base} $相比,作为使用的分类器。我们评估两个NLP分类数据集的算法:斯坦福情绪树木银行和kvk-Front页面。此外,我们探讨了旨在解决不确定性的al的预定问题的启发式;即,它是不可规范的,并且易于选择异常值。此外,我们探讨了查询池大小对al的性能的影响。虽然发现,AL的拟议启发式没有提高AL的表现;我们的结果表明,使用BERT $ _ {Base} $概率使用不确定性的AL。随着查询池大小变大,性能的这种差异可以减少。
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我们提出了一种新的方法来捕获神经网络中决策边界附近的数据点,这些点通常被称为特定类型的不确定性。在我们的方法中,我们试图根据对抗攻击方法的思想来执行不确定性估计。在本文中,不确定估计来自输入扰动,与之前的研究不同,这些研究可以在贝叶斯方法中提供对模型参数的扰动。我们能够在投入中产生与扰动的关系的不确定性。有趣的是,我们将建议的方法应用于来自区块链的数据集。我们将模型不确定性的性能与最近的不确定性方法进行比较。我们表明,该方法揭示了对其他方法的显着优势,并且在机器学习中捕获模型不确定性的风险较小。
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Deep neural networks (NNs) are powerful black box predictors that have recently achieved impressive performance on a wide spectrum of tasks. Quantifying predictive uncertainty in NNs is a challenging and yet unsolved problem. Bayesian NNs, which learn a distribution over weights, are currently the state-of-the-art for estimating predictive uncertainty; however these require significant modifications to the training procedure and are computationally expensive compared to standard (non-Bayesian) NNs. We propose an alternative to Bayesian NNs that is simple to implement, readily parallelizable, requires very little hyperparameter tuning, and yields high quality predictive uncertainty estimates. Through a series of experiments on classification and regression benchmarks, we demonstrate that our method produces well-calibrated uncertainty estimates which are as good or better than approximate Bayesian NNs. To assess robustness to dataset shift, we evaluate the predictive uncertainty on test examples from known and unknown distributions, and show that our method is able to express higher uncertainty on out-of-distribution examples. We demonstrate the scalability of our method by evaluating predictive uncertainty estimates on ImageNet.
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Large, labeled datasets have driven deep learning methods to achieve expert-level performance on a variety of medical imaging tasks. We present CheXpert, a large dataset that contains 224,316 chest radiographs of 65,240 patients. We design a labeler to automatically detect the presence of 14 observations in radiology reports, capturing uncertainties inherent in radiograph interpretation. We investigate different approaches to using the uncertainty labels for training convolutional neural networks that output the probability of these observations given the available frontal and lateral radiographs. On a validation set of 200 chest radiographic studies which were manually annotated by 3 board-certified radiologists, we find that different uncertainty approaches are useful for different pathologies. We then evaluate our best model on a test set composed of 500 chest radiographic studies annotated by a consensus of 5 board-certified radiologists, and compare the performance of our model to that of 3 additional radiologists in the detection of 5 selected pathologies. On Cardiomegaly, Edema, and Pleural Effusion, the model ROC and PR curves lie above all 3 radiologist operating points. We release the dataset to the public as a standard benchmark to evaluate performance of chest radiograph interpretation models. 1
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机器学习(ML)越来越多地用于支持高风险的决策,这是由于其相对于人类评估的优势预测能力的承诺而欠的趋势。但是,决策目标与观察到的作为训练ML模型的标签的结果中捕获的内容之间经常存在差距。结果,机器学习模型可能无法捕获决策标准的重要维度,从而阻碍了他们的决策支持。在这项工作中,我们探讨了历史专家决策作为组织信息系统中通常可用的丰富(但不完美)的信息来源,并表明它可以利用它来弥合决策目标与算法目标之间的差距。当数据中的每个案例都由单个专家评估并提出基于影响函数的方法作为解决此问题的解决方案时,我们会间接考虑估计专家一致性的问题。然后,我们将估计的专家一致性通过培训时间标签合并方法纳入预测模型。这种方法使ML模型可以在有推断的专家一致性和观察标签的情况下向专家学习。我们还提出了通过混合和延期模型来利用推断一致性的替代方法。在我们的经验评估中,专注于儿童虐待热线筛查的背景下,我们表明(1)有一些高风险案例,其风险是专家考虑的,但在目标标签中没有完全捕获用于培训已部署模型和培训的目标标签(2)提出的方法可显着提高这些情况的精度。
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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
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智能手表或健身追踪器由于负担得起和纵向监测功能而获得了潜在的健康跟踪设备的广泛欢迎。为了进一步扩大其健康跟踪能力,近年来,研究人员开始研究在实时利用光摄影学(PPG)数据中进行心房颤动(AF)检测的可能性,这是一种几乎所有智能手表中广泛使用的廉价传感器。从PPG信号检测AF检测的重大挑战来自智能手表PPG信号中的固有噪声。在本文中,我们提出了一种基于深度学习的新方法,即利用贝叶斯深度学习的力量来准确地从嘈杂的PPG信号中推断出AF风险,同时提供了预测的不确定性估计。在两个公开可用数据集上进行的广泛实验表明,我们提出的方法贝尼斯甲的表现优于现有的最新方法。此外,贝内斯比特(Bayesbeat)的参数比最先进的基线方法要少40-200倍,使其适合在资源约束可穿戴设备中部署。
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由于结构化数据通常不足,因此在开发用于临床信息检索和决策支持系统模型时,需要从电子健康记录中的自由文本中提取标签。临床文本中最重要的上下文特性之一是否定,这表明没有发现。我们旨在通过比较荷兰临床注释中的三种否定检测方法来改善标签的大规模提取。我们使用Erasmus医疗中心荷兰临床语料库比较了基于ContextD的基于规则的方法,即使用MEDCAT和(Fineted)基于Roberta的模型的BilstM模型。我们发现,Bilstm和Roberta模型都在F1得分,精度和召回方面始终优于基于规则的模型。此外,我们将每个模型的分类错误系统地分类,这些错误可用于进一步改善特定应用程序的模型性能。在性能方面,将三个模型结合起来并不有益。我们得出的结论是,尤其是基于Bilstm和Roberta的模型在检测临床否定方面非常准确,但是最终,根据手头的用例,这三种方法最终都可以可行。
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Modern machine learning methods including deep learning have achieved great success in predictive accuracy for supervised learning tasks, but may still fall short in giving useful estimates of their predictive uncertainty. Quantifying uncertainty is especially critical in real-world settings, which often involve input distributions that are shifted from the training distribution due to a variety of factors including sample bias and non-stationarity. In such settings, well calibrated uncertainty estimates convey information about when a model's output should (or should not) be trusted. Many probabilistic deep learning methods, including Bayesian-and non-Bayesian methods, have been proposed in the literature for quantifying predictive uncertainty, but to our knowledge there has not previously been a rigorous largescale empirical comparison of these methods under dataset shift. We present a largescale benchmark of existing state-of-the-art methods on classification problems and investigate the effect of dataset shift on accuracy and calibration. We find that traditional post-hoc calibration does indeed fall short, as do several other previous methods. However, some methods that marginalize over models give surprisingly strong results across a broad spectrum of tasks.
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神经线性模型(NLM)是深度贝叶斯模型,通过从数据中学习特征,然后对这些特征进行贝叶斯线性回归来产生预测的不确定性。尽管他们受欢迎,但很少有作品专注于有条理地评估这些模型的预测性不确定性。在这项工作中,我们证明了NLMS的传统培训程序急剧低估了分发输入的不确定性,因此它们不能在风险敏感的应用中暂时部署。我们确定了这种行为的基本原因,并提出了一种新的培训框架,捕获下游任务的有用预测不确定性。
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随着我们远离数据,预测不确定性应该增加,因为各种各样的解释与鲜为人知的信息一致。我们引入了远距离感知的先验(DAP)校准,这是一种纠正训练域之外贝叶斯深度学习模型过度自信的方法。我们将DAPS定义为模型参数的先验分布,该模型参数取决于输入,通过其与训练集的距离度量。DAP校准对后推理方法不可知,可以作为后处理步骤进行。我们证明了其在各种分类和回归问题中对几个基线的有效性,包括旨在测试远离数据的预测分布质量的基准。
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部署在医学成像任务上的机器学习模型必须配备分布外检测功能,以避免错误的预测。不确定依赖于深神经网络的分布外检测模型是否适合检测医学成像中的域移位。高斯流程可以通过其数学结构可靠地与分布数据点可靠地分开分发数据点。因此,我们为分层卷积高斯工艺提出了一个参数有效的贝叶斯层,该过程融合了在Wasserstein-2空间中运行的高斯过程,以可靠地传播不确定性。这直接用远距离的仿射操作员在分布中直接取代了高斯流程。我们对脑组织分割的实验表明,所得的架构接近了确定性分割算法(U-NET)的性能,而先前的层次高斯过程尚未实现。此外,通过将相同的分割模型应用于分布外数据(即具有病理学(例如脑肿瘤)的图像),我们表明我们的不确定性估计导致分布外检测,以优于以前的贝叶斯网络和以前的贝叶斯网络的功能基于重建的方法学习规范分布。为了促进未来的工作,我们的代码公开可用。
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