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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心肌的准确分割和运动估计在临床领域一直很重要,这基本上有助于下游诊断。但是,现有方法不能始终保证心肌分割的形状完整性。此外,运动估计需要在不同帧上对心肌区域的点对应关系。在本文中,我们提出了一种新型的端到端深度统计形状模型,以关注具有形状完整性和边界对应关系的心肌分割。具体而言,心肌形状由固定数量的点表示,其变化是通过主成分分析(PCA)提取的。深神经网络用于预测转换参数(仿射和变形),然后将其用于将平均点云转转到图像域。此外,引入了一个可区分的渲染层,以将掩码的监督纳入框架中,以了解更准确的点云。通过这种方式,所提出的方法能够在不进行后处理的情况下始终如一地产生解剖上合理的分割掩码。此外,预测的点云还保证了顺序图像的边界对应关系,这有助于下游任务,例如心肌的运动估计。我们进行了几项实验,以证明在几个基准数据集上提出的方法的有效性。
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我们介绍了软件Robustar的初步发布,该版本旨在通过数据驱动的视角提高视觉分类机器学习模型的鲁棒性。基于最近的理解,即缺乏机器学习模型的鲁棒性是该模型学习虚假特征的趋势,我们旨在通过在训练前从数据中删除数据的杂种特征来从数据角度解决此问题。特别是,我们介绍了一种软件,可以通过允许用户注释图像像素级别的虚假功能来帮助用户更好地为训练图像分类模型准备数据。为了促进这一过程,我们的软件还利用了最近的进步来帮助识别值得关注的潜在图像和像素,并通过新注释的数据继续培训。我们的软件托管在GitHub存储库https://github.com/haohanwang/robustar。
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符号知识图(kgs)是通过昂贵的人众包或特定于域特异性的复杂信息提取管道来构建的。诸如BERT之类的新兴大型语言模型(LMS)已显示出隐式编码的大量知识,可以使用正确设计的提示来查询。但是,与明确的公斤相比,黑盒LMS中的知识通常很难访问或编辑,并且缺乏解释性。在这项工作中,我们旨在从LMS收获符号KG,这是一个由神经LMS的灵活性和可扩展性增强的自动kg构造的新框架。与通常依赖大型人类注释的数据或现有大量KG的先前作品相比,我们的方法仅需要对关系的最小定义作为输入,因此适合于以前无法提取有关丰富新关系的知识。该方法会自动生成多样化的提示,并在给定的LM内执行有效的知识搜索,以进行一致和广泛的输出。与以前的方法相比,使用我们的方法收获的知识要准确得多,如自动和人类评估所示。结果,我们源于多元化的LMS,一个新的KG家族(例如Bertnet和Robertanet),其中包含一套更丰富的常识关系,包括复杂的关系(例如,A对B的能力,但不擅长B”)人类注销的kg(例如概念网)。此外,由此产生的kg也是解释各自的源LMS的工具,从而导致对不同LMS不同知识能力的新见解。
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为了以计算有效的方式部署深层模型,经常使用模型量化方法。此外,由于新的硬件支持混合的位算术操作,最近对混合精度量化(MPQ)的研究开始通过搜索网络中不同层和模块的优化位低宽,从而完全利用表示的能力。但是,先前的研究主要是在使用强化学习,神经体系结构搜索等的昂贵方案中搜索MPQ策略,或者简单地利用部分先验知识来进行位于刻度分配,这可能是有偏见和优势的。在这项工作中,我们提出了一种新颖的随机量化量化(SDQ)方法,该方法可以在更灵活,更全球优化的空间中自动学习MPQ策略,并具有更平滑的梯度近似。特别是,可区分的位宽参数(DBP)被用作相邻位意选择之间随机量化的概率因素。在获取最佳MPQ策略之后,我们将进一步训练网络使用熵感知的bin正则化和知识蒸馏。我们广泛评估了不同硬件(GPU和FPGA)和数据集的多个网络的方法。 SDQ的表现优于所有最先进的混合或单个精度量化,甚至比较低的位置量化,甚至比各种重新网络和Mobilenet家族的全精度对应物更好,这表明了我们方法的有效性和优势。
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视觉变压器(VIT)显示了计算机视觉任务的快速进步,在各种基准上取得了令人鼓舞的结果。但是,由于参数和模型设计的数量大量,例如注意机制,基于VIT的模型通常比轻型卷积网络慢。因此,为实时应用程序部署VIT特别具有挑战性,尤其是在资源受限的硬件(例如移动设备)上。最近的努力试图通过网络体系结构搜索或与Mobilenet块的混合设计来降低VIT的计算复杂性,但推理速度仍然不令人满意。这导致了一个重要的问题:变形金刚在获得高性能的同时可以像Mobilenet一样快吗?为了回答这一点,我们首先重新审视基于VIT的模型中使用的网络体系结构和运营商,并确定效率低下的设计。然后,我们引入了一个尺寸一致的纯变压器(无需Mobilenet块)作为设计范式。最后,我们执行以延迟驱动的缩小,以获取一系列称为EfficityFormer的最终模型。广泛的实验表明,在移动设备上的性能和速度方面,有效形式的优势。我们最快的型号,EfficientFormer-L1,在ImagEnet-1k上获得$ 79.2 \%$ $ TOP-1的准确性,仅$ 1.6 $ MS推理潜伏期在iPhone 12上(与Coreml一起编译),该{运行速度与MobileNetV2 $ \ Times Times 1.4 $( $ 1.6 $ MS,$ 74.7 \%$ top-1),我们最大的型号EfficientFormer-L7,获得了$ 83.3 \%$精度,仅$ 7.0 $ MS延迟。我们的工作证明,正确设计的变压器可以在移动设备上达到极低的延迟,同时保持高性能。
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图级表示在各种现实世界中至关重要,例如预测分子的特性。但是实际上,精确的图表注释通常非常昂贵且耗时。为了解决这个问题,图形对比学习构造实例歧视任务,将正面对(同一图的增强对)汇总在一起,并将负面对(不同图的增强对)推开,以进行无监督的表示。但是,由于为了查询,其负面因素是从所有图中均匀抽样的,因此现有方法遭受关键采样偏置问题的损失,即,否定物可能与查询具有相同的语义结构,从而导致性能降解。为了减轻这种采样偏见问题,在本文中,我们提出了一种典型的图形对比度学习(PGCL)方法。具体而言,PGCL通过将语义相似的图形群群归为同一组的群集数据的基础语义结构,并同时鼓励聚类的一致性,以实现同一图的不同增强。然后给出查询,它通过从与查询群集不同的群集中绘制图形进行负采样,从而确保查询及其阴性样本之间的语义差异。此外,对于查询,PGCL根据其原型(集群质心)和查询原型之间的距离进一步重新重新重新重新重新享受其负样本,从而使那些具有中等原型距离的负面因素具有相对较大的重量。事实证明,这种重新加权策略比统一抽样更有效。各种图基准的实验结果证明了我们的PGCL比最新方法的优势。代码可在https://github.com/ha-lins/pgcl上公开获取。
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We introduce scalable deep kernels, which combine the structural properties of deep learning architectures with the non-parametric flexibility of kernel methods. Specifically, we transform the inputs of a spectral mixture base kernel with a deep architecture, using local kernel interpolation, inducing points, and structure exploiting (Kronecker and Toeplitz) algebra for a scalable kernel representation. These closed-form kernels can be used as drop-in replacements for standard kernels, with benefits in expressive power and scalability. We jointly learn the properties of these kernels through the marginal likelihood of a Gaussian process. Inference and learning cost O(n) for n training points, and predictions cost O(1) per test point. On a large and diverse collection of applications, including a dataset with 2 million examples, we show improved performance over scalable Gaussian processes with flexible kernel learning models, and stand-alone deep architectures.
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Non-linear state-space models, also known as general hidden Markov models, are ubiquitous in statistical machine learning, being the most classical generative models for serial data and sequences in general. The particle-based, rapid incremental smoother PaRIS is a sequential Monte Carlo (SMC) technique allowing for efficient online approximation of expectations of additive functionals under the smoothing distribution in these models. Such expectations appear naturally in several learning contexts, such as likelihood estimation (MLE) and Markov score climbing (MSC). PARIS has linear computational complexity, limited memory requirements and comes with non-asymptotic bounds, convergence results and stability guarantees. Still, being based on self-normalised importance sampling, the PaRIS estimator is biased. Our first contribution is to design a novel additive smoothing algorithm, the Parisian particle Gibbs PPG sampler, which can be viewed as a PaRIS algorithm driven by conditional SMC moves, resulting in bias-reduced estimates of the targeted quantities. We substantiate the PPG algorithm with theoretical results, including new bounds on bias and variance as well as deviation inequalities. Our second contribution is to apply PPG in a learning framework, covering MLE and MSC as special examples. In this context, we establish, under standard assumptions, non-asymptotic bounds highlighting the value of bias reduction and the implicit Rao--Blackwellization of PPG. These are the first non-asymptotic results of this kind in this setting. We illustrate our theoretical results with numerical experiments supporting our claims.
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While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.
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