Coronary Computed Tomography Angiography (CCTA) provides information on the presence, extent, and severity of obstructive coronary artery disease. Large-scale clinical studies analyzing CCTA-derived metrics typically require ground-truth validation in the form of high-fidelity 3D intravascular imaging. However, manual rigid alignment of intravascular images to corresponding CCTA images is both time consuming and user-dependent. Moreover, intravascular modalities suffer from several non-rigid motion-induced distortions arising from distortions in the imaging catheter path. To address these issues, we here present a semi-automatic segmentation-based framework for both rigid and non-rigid matching of intravascular images to CCTA images. We formulate the problem in terms of finding the optimal \emph{virtual catheter path} that samples the CCTA data to recapitulate the coronary artery morphology found in the intravascular image. We validate our co-registration framework on a cohort of $n=40$ patients using bifurcation landmarks as ground truth for longitudinal and rotational registration. Our results indicate that our non-rigid registration significantly outperforms other co-registration approaches for luminal bifurcation alignment in both longitudinal (mean mismatch: 3.3 frames) and rotational directions (mean mismatch: 28.6 degrees). By providing a differentiable framework for automatic multi-modal intravascular data fusion, our developed co-registration modules significantly reduces the manual effort required to conduct large-scale multi-modal clinical studies while also providing a solid foundation for the development of machine learning-based co-registration approaches.
translated by 谷歌翻译
Previous work has shown that a neural network with the rectified linear unit (ReLU) activation function leads to a convex polyhedral decomposition of the input space. These decompositions can be represented by a dual graph with vertices corresponding to polyhedra and edges corresponding to polyhedra sharing a facet, which is a subgraph of a Hamming graph. This paper illustrates how one can utilize the dual graph to detect and analyze adversarial attacks in the context of digital images. When an image passes through a network containing ReLU nodes, the firing or non-firing at a node can be encoded as a bit ($1$ for ReLU activation, $0$ for ReLU non-activation). The sequence of all bit activations identifies the image with a bit vector, which identifies it with a polyhedron in the decomposition and, in turn, identifies it with a vertex in the dual graph. We identify ReLU bits that are discriminators between non-adversarial and adversarial images and examine how well collections of these discriminators can ensemble vote to build an adversarial image detector. Specifically, we examine the similarities and differences of ReLU bit vectors for adversarial images, and their non-adversarial counterparts, using a pre-trained ResNet-50 architecture. While this paper focuses on adversarial digital images, ResNet-50 architecture, and the ReLU activation function, our methods extend to other network architectures, activation functions, and types of datasets.
translated by 谷歌翻译
This report presents the evaluation approach developed for the DARPA Big Mechanism program, which aimed at developing computer systems that will read research papers, integrate the information into a computer model of cancer mechanisms, and frame new hypotheses. We employed an iterative, incremental approach to the evaluation of the three phases of the program. In Phase I, we evaluated the ability of system and human teams ability to read-with-a-model to capture mechanistic information from the biomedical literature, integrated with information from expert curated biological databases. In Phase II we evaluated the ability of systems to assemble fragments of information into a mechanistic model. The Phase III evaluation focused on the ability of systems to provide explanations of experimental observations based on models assembled (largely automatically) by the Big Mechanism process. The evaluation for each phase built on earlier evaluations and guided developers towards creating capabilities for the new phase. The report describes our approach, including innovations such as a reference set (a curated data set limited to major findings of each paper) to assess the accuracy of systems in extracting mechanistic findings in the absence of a gold standard, and a method to evaluate model-based explanations of experimental data. Results of the evaluation and supporting materials are included in the appendices.
translated by 谷歌翻译
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.
translated by 谷歌翻译
ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列,该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战,这是由于探测器的几何形状,不均匀的散射和冰中光的吸收,并且低于100 GEV的光,每个事件产生的信号光子数量相对较少。为了应对这一挑战,可以将ICECUBE事件表示为点云图形,并将图形神经网络(GNN)作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开,对不同的中微子事件类型进行分类,并重建沉积的能量,方向和相互作用顶点。基于仿真,我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术,包括已知系统不确定性的影响。对于中微子事件分类,与当前的IceCube方法相比,GNN以固定的假阳性速率(FPR)提高了信号效率的18%。另外,GNN在固定信号效率下将FPR的降低超过8(低于半百分比)。对于能源,方向和相互作用顶点的重建,与当前最大似然技术相比,分辨率平均提高了13%-20%。当在GPU上运行时,GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件,这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。
translated by 谷歌翻译
“技术彩票”描述了一种研究思想或技术,因为它适合可用的软件和硬件,而不一定是因为它优于替代方向 - 审查是从深度学习和GPU的协同作用到GPU的协同效应,城市设计和自动驾驶汽车的断开连接。自动驾驶实验室(SDL)的新生领域,尤其是作为材料加速平台(地图)实施的新生领域,有类似陷阱的风险:构建地图的下一个逻辑步骤是采用现有的实验室设备和工作流并混合一些AI和自动化。在此白皮书中,我们认为,作为地图研究计划的一部分,将加速搜索新材料的相同模拟和AI工具也使得设计了根本新的计算媒体的设计。我们不必受到科学,机电一体化和通用计算的现有偏见的限制,而是我们可以通过网络物理学习和闭环,自我优化系统来追求工程物理学的新向量。在这里,我们概述了一个基于仿真的地图程序来设计使用物理本身来解决优化问题的计算机。这样的系统减轻了其他每类地图中存在的硬件软件 - 材料用户信息损失,并且它们在计算问题和计算介质之间完全对齐消除了任何技术彩票。我们提供了迈向早期“物理计算(PC)-MAP”进步的具体步骤,以及我们希望在材料研究人员和计算机科学家之间引入创新合作的新时代。
translated by 谷歌翻译
团队是人类成就的核心。在过去的半个世纪中,心理学家已经确定了五个跨文化有效的人格变量:神经质,外向性,开放性,尽职尽责和同意。前四个与团队绩效显示一致的关系。然而,令人愉快的(和谐,无私,谦虚和合作)表现出与团队绩效的无关紧要和高度可变的关系。我们通过计算建模解决这种不一致。基于代理的模型(ABM)用于预测人格特质对团队合作的影响,然后使用遗传算法来探索ABM的限制,以发现哪种特征与最佳和最差的表现相关,以解决与与最差的团队相关的问题,以解决与问题有关的问题。不同级别的不确定性(噪声)。探索所揭示的新依赖性通过分析迄今为止最大的团队绩效数据集的先前未观察到的数据来证实,其中包括593个团队中的3,698个个人,从事5,000多个没有不确定性的小组任务,在10年内收集了不确定性。我们的发现是,团队绩效和同意之间的依赖性受到任务不确定性的调节。以这种方式将进化计算与ABM相结合,为团队合作的科学研究,做出新的预测以及提高我们对人类行为的理解提供了一种新方法。我们的结果证实了计算机建模对发展理论的潜在实用性,并阐明了随着工作环境的越来越流畅和不确定的启示。
translated by 谷歌翻译
非结构化的文本中存在大量的位置信息,例如社交媒体帖子,新闻报道,科学文章,网页,旅行博客和历史档案。地理学是指识别文本中的位置参考并识别其地理空间表示的过程。虽然地理标准可以使许多领域受益,但仍缺少特定应用程序的摘要。此外,缺乏对位置参考识别方法的现有方法的全面审查和比较,这是地理验证的第一个和核心步骤。为了填补这些研究空白,这篇综述首先总结了七个典型的地理应用程序域:地理信息检索,灾难管理,疾病监视,交通管理,空间人文,旅游管理和犯罪管理。然后,我们通过将这些方法分类为四个组,以基于规则的基于规则,基于统计学学习的基于统计学学习和混合方法将这些方法分类为四个组,从而回顾了现有的方法参考识别方法。接下来,我们彻底评估了27种最广泛使用的方法的正确性和计算效率,该方法基于26个公共数据集,其中包含不同类型的文本(例如,社交媒体帖子和新闻报道),包含39,736个位置参考。这项彻底评估的结果可以帮助未来的方法论发展以获取位置参考识别,并可以根据应用需求指导选择适当方法的选择。
translated by 谷歌翻译
联合学习中的隐私(FL)以两种不同的粒度进行了研究:项目级,该项目级别保护单个数据点和用户级别,该数据点保护联邦中的每个用户(参与者)。几乎所有的私人文献都致力于研究这两种粒度的隐私攻击和防御。最近,主题级隐私已成为一种替代性隐私粒度,以保护个人(数据主体)的隐私(数据主题),其数据分布在跨索洛FL设置中的多个(组织)用户。对手可能有兴趣通过攻击受过训练的模型来恢复有关这些人(又称emph {data主体})的私人信息。对这些模式的系统研究需要对联邦的完全控制,而实际数据集是不可能的。我们设计了一个模拟器,用于生成各种合成联邦配置,使我们能够研究数据的属性,模型设计和培训以及联合会本身如何影响主题隐私风险。我们提出了\ emph {主题成员推理}的三个攻击,并检查影响攻击功效的联邦中所有因素之间的相互作用。我们还研究了差异隐私在减轻这种威胁方面的有效性。我们的收获概括到像女权主义者这样的现实世界数据集中,对我们的发现赋予了信任。
translated by 谷歌翻译
生物医学机器阅读理解(生物医学MRC)旨在理解复杂的生物医学叙事,并协助医疗保健专业人员从中检索信息。现代神经网络的MRC系统的高性能取决于高质量的大规模,人为宣传的培训数据集。在生物医学领域中,创建此类数据集的一个至关重要的挑战是域知识的要求,引起了标记数据的稀缺性以及从标记的通用(源)域转移学习到生物医学(目标)域的需求。然而,由于主题方差,通用和生物医学领域之间的边际分布存在差异。因此,从在通用域上训练的模型到生物医学领域的模型直接转移学会的表示可能会损害模型的性能。我们为生物医学机器阅读理解任务(BioAdapt-MRC)提供了基于对抗性学习的域适应框架,这是一种基于神经网络的方法,可解决一般和生物医学域数据之间边际分布中的差异。 Bioadapt-MRC松弛了生成伪标签的需求,以训练表现出色的生物医学MRC模型。我们通过将生物ADAPT-MRC与三种广泛使用的基准生物医学MRC数据集进行比较,从而广泛评估了生物ADAPT-MRC的性能-Bioasq-7B,BioASQ-8B和BioASQ-9B。我们的结果表明,如果不使用来自生物医学领域的任何合成或人类通知的数据,Bioadapt-MRC可以在这些数据集中实现最先进的性能。可用性:bioadapt-MRC可作为开放源项目免费获得,\ url {https://github.com/mmahbub/bioadapt-mrc}。
translated by 谷歌翻译