Artificial Intelligence (AI) is having a tremendous impact across most areas of science. Applications of AI in healthcare have the potential to improve our ability to detect, diagnose, prognose, and intervene on human disease. For AI models to be used clinically, they need to be made safe, reproducible and robust, and the underlying software framework must be aware of the particularities (e.g. geometry, physiology, physics) of medical data being processed. This work introduces MONAI, a freely available, community-supported, and consortium-led PyTorch-based framework for deep learning in healthcare. MONAI extends PyTorch to support medical data, with a particular focus on imaging, and provide purpose-specific AI model architectures, transformations and utilities that streamline the development and deployment of medical AI models. MONAI follows best practices for software-development, providing an easy-to-use, robust, well-documented, and well-tested software framework. MONAI preserves the simple, additive, and compositional approach of its underlying PyTorch libraries. MONAI is being used by and receiving contributions from research, clinical and industrial teams from around the world, who are pursuing applications spanning nearly every aspect of healthcare.
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Federated learning (FL) enables the building of robust and generalizable AI models by leveraging diverse datasets from multiple collaborators without centralizing the data. We created NVIDIA FLARE as an open-source software development kit (SDK) to make it easier for data scientists to use FL in their research and real-world applications. The SDK includes solutions for state-of-the-art FL algorithms and federated machine learning approaches, which facilitate building workflows for distributed learning across enterprises and enable platform developers to create a secure, privacy-preserving offering for multiparty collaboration utilizing homomorphic encryption or differential privacy. The SDK is a lightweight, flexible, and scalable Python package, and allows researchers to bring their data science workflows implemented in any training libraries (PyTorch, TensorFlow, XGBoost, or even NumPy) and apply them in real-world FL settings. This paper introduces the key design principles of FLARE and illustrates some use cases (e.g., COVID analysis) with customizable FL workflows that implement different privacy-preserving algorithms. Code is available at https://github.com/NVIDIA/NVFlare.
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已经提出了分裂学习(SL)以分散的方式训练深度学习模型。对于具有垂直数据分配的分散医疗保健应用,SL可以有益,因为它允许具有互补功能或图像的机构为一组共享的患者共同开发更强大且可推广的模型。在这项工作中,我们提出了“ split-u-net”,并成功地将SL应用于协作生物医学图像分割。但是,SL需要交换中间激活图和梯度,以允许跨不同特征空间的训练模型,这可能会泄漏数据并提高隐私问题。因此,我们还量化了用于生物医学图像分割的常见SL情况下的数据泄漏量,并通过应用适当的防御策略提供了抵消此类泄漏的方法。
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联合学习(FL)是一种分布式机器学习技术,可以在避免明确的数据共享的同时进行协作模型培训。 FL算法的固有保护属性使其对医疗领域特别有吸引力。但是,如果有异质的客户数据分布,则标准FL方法是不稳定的,需要密集的超参数调整以实现最佳性能。常规的超参数优化算法在现实世界中的FL应用中是不切实际的,因为它们涉及大量的培训试验,而计算预算有限,这些试验通常是不起作用的。在这项工作中,我们提出了一种有效的增强学习(RL)的联合次数超参数优化算法,称为自动FEDRL,其中在线RL代理可以根据当前的培训进度动态调整每个客户的超参数。进行了广泛的实验以研究不同的搜索策略和RL代理。该方法的有效性在CIFAR-10数据集的异质数据分配以及两个现实世界中的医学图像分割数据集上进行了验证,用于胸部CT中的COVID-19变病变分段,腹部CT中的胰腺细分。
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医学成像的病变分割是临床研究中的一个重要课题。研究人员提出了各种检测和分段算法来解决这项任务。最近,基于深度学习的方法显着提高了传统方法的性能。然而,大多数最先进的深度学习方法需要手动设计多个网络组件和培训策略。在本文中,我们提出了一种新的自动化机器学习算法T-Automl,不仅搜索最佳神经结构,而且还可以同时找到超参数和数据增强策略的最佳组合。该方法采用现代变压器模型,引入了适应搜索空间嵌入的动态长度,并且可以显着提高搜索能力。我们在几个大型公共病变分割数据集上验证T-Automl并实现最先进的性能。
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多实例学习(MIL)是整个幻灯片图像(WSI)分类的关键算法。组织学WSIS可以具有数十亿像素,它创造了巨大的计算和注释挑战。通常,这种图像被分成一组贴片(一袋实例),其中仅提供袋级类标签。基于深度学习的MIL方法使用卷积神经网络(CNN)计算实例特征。我们所提出的方法也是基于深度学习的,随着以下两项贡献例如,肿瘤等级可以取决于WSI中不同位置的几种特定模式的存在,这需要考虑贴片之间的依赖性。其次,我们提出了基于实例伪标签的实例 - 明智函数。我们将所提出的算法与多个基线方法进行比较,在熊猫挑战数据集上评估它,该数据集是超过11K图像的最大可用的WSI数据集,并展示最先进的结果。
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Feature transformation for AI is an essential task to boost the effectiveness and interpretability of machine learning (ML). Feature transformation aims to transform original data to identify an optimal feature space that enhances the performances of a downstream ML model. Existing studies either combines preprocessing, feature selection, and generation skills to empirically transform data, or automate feature transformation by machine intelligence, such as reinforcement learning. However, existing studies suffer from: 1) high-dimensional non-discriminative feature space; 2) inability to represent complex situational states; 3) inefficiency in integrating local and global feature information. To fill the research gap, we formulate the feature transformation task as an iterative, nested process of feature generation and selection, where feature generation is to generate and add new features based on original features, and feature selection is to remove redundant features to control the size of feature space. Finally, we present extensive experiments and case studies to illustrate 24.7\% improvements in F1 scores compared with SOTAs and robustness in high-dimensional data.
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We summarize our TRECVID 2022 Ad-hoc Video Search (AVS) experiments. Our solution is built with two new techniques, namely Lightweight Attentional Feature Fusion (LAFF) for combining diverse visual / textual features and Bidirectional Negation Learning (BNL) for addressing queries that contain negation cues. In particular, LAFF performs feature fusion at both early and late stages and at both text and video ends to exploit diverse (off-the-shelf) features. Compared to multi-head self attention, LAFF is much more compact yet more effective. Its attentional weights can also be used for selecting fewer features, with the retrieval performance mostly preserved. BNL trains a negation-aware video retrieval model by minimizing a bidirectionally constrained loss per triplet, where a triplet consists of a given training video, its original description and a partially negated description. For video feature extraction, we use pre-trained CLIP, BLIP, BEiT, ResNeXt-101 and irCSN. As for text features, we adopt bag-of-words, word2vec, CLIP and BLIP. Our training data consists of MSR-VTT, TGIF and VATEX that were used in our previous participation. In addition, we automatically caption the V3C1 collection for pre-training. The 2022 edition of the TRECVID benchmark has again been a fruitful participation for the RUCMM team. Our best run, with an infAP of 0.262, is ranked at the second place teamwise.
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Adding perturbations via utilizing auxiliary gradient information or discarding existing details of the benign images are two common approaches for generating adversarial examples. Though visual imperceptibility is the desired property of adversarial examples, conventional adversarial attacks still generate traceable adversarial perturbations. In this paper, we introduce a novel Adversarial Attack via Invertible Neural Networks (AdvINN) method to produce robust and imperceptible adversarial examples. Specifically, AdvINN fully takes advantage of the information preservation property of Invertible Neural Networks and thereby generates adversarial examples by simultaneously adding class-specific semantic information of the target class and dropping discriminant information of the original class. Extensive experiments on CIFAR-10, CIFAR-100, and ImageNet-1K demonstrate that the proposed AdvINN method can produce less imperceptible adversarial images than the state-of-the-art methods and AdvINN yields more robust adversarial examples with high confidence compared to other adversarial attacks.
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图对比度学习(GCL)一直是图形自学学习的新兴解决方案。 GCL的核心原理是在正视图中降低样品之间的距离,但在负视图中增加样品之间的距离。在实现有希望的性能的同时,当前的GCL方法仍然受到两个局限性:(1)增强的不可控制的有效性,该图扰动可能会产生针对语义和图形数据的特征流程的无效视图; (2)不可靠的二进制对比理由,对于非欧几里得图数据而言,难以确定构造观点的积极性和负面性。为了应对上述局限性,我们提出了一个新的对比度学习范式,即图形软对比度学习(GSCL),该范例通过排名的社区无需任何增强和二进制对比符合性,在较细性的范围内进行对比度学习。 GSCL建立在图接近的基本假设上,即连接的邻居比遥远的节点更相似。具体而言,我们在配对和列表的封闭式排名中,以保留附近的相对排名关系。此外,随着邻里规模的指数增长,考虑了更多的啤酒花,我们提出了提高学习效率的邻里抽样策略。广泛的实验结果表明,我们提出的GSCL可以始终如一地在各种公共数据集上实现与GCL相当复杂的各种公共数据集的最新性能。
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