左心室(LV)功能是心脏病患者的患者管理,结局和长期存活方面的重要因素。最近发表的心力衰竭临床指南认识到,仅依赖一种心脏功能(LV射血分数)作为诊断和治疗分层生物标志物的依赖是次优。基于AI的超声心动图分析的最新进展已在LV体积和LV射血分数的自动估计上显示出良好的结果。但是,从随时间变化的2D超声心动图摄取,可以通过从完整的心脏周期中估算功能性生物标志物来获得对心脏功能的更丰富的描述。在这项工作中,我们首次提出了一种基于全心脏周期分割的2D超声心动图的AI方法,用于从2D超声心动图中得出高级生物标志物。这些生物标志物将允许临床医生获得健康和疾病中心脏的丰富图片。 AI模型基于“ NN-UNET”框架,并使用四个不同的数据库进行了训练和测试。结果表明,手动分析和自动分析之间的一致性很高,并展示了晚期收缩期和舒张期生物标志物在患者分层中的潜力。最后,对于50例病例的子集,我们在超声心动图和CMR的临床生物标志物之间进行了相关分析,我们在两种方式之间表现出了极好的一致性。
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A new method for solving the wave equation is presented, called the learned Born series (LBS), which is derived from a convergent Born Series but its components are found through training. The LBS is shown to be significantly more accurate than the convergent Born series for the same number of iterations, in the presence of high contrast scatterers, while maintaining a comparable computational complexity. The LBS is able to generate a reasonable prediction of the global pressure field with a small number of iterations, and the errors decrease with the number of learned iterations.
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Whether based on models, training data or a combination, classifiers place (possibly complex) input data into one of a relatively small number of output categories. In this paper, we study the structure of the boundary--those points for which a neighbor is classified differently--in the context of an input space that is a graph, so that there is a concept of neighboring inputs, The scientific setting is a model-based naive Bayes classifier for DNA reads produced by Next Generation Sequencers. We show that the boundary is both large and complicated in structure. We create a new measure of uncertainty, called Neighbor Similarity, that compares the result for a point to the distribution of results for its neighbors. This measure not only tracks two inherent uncertainty measures for the Bayes classifier, but also can be implemented, at a computational cost, for classifiers without inherent measures of uncertainty.
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Media bias can significantly impact the formation and development of opinions and sentiments in a population. It is thus important to study the emergence and development of partisan media and political polarization. However, it is challenging to quantitatively infer the ideological positions of media outlets. In this paper, we present a quantitative framework to infer both political bias and content quality of media outlets from text, and we illustrate this framework with empirical experiments with real-world data. We apply a bidirectional long short-term memory (LSTM) neural network to a data set of more than 1 million tweets to generate a two-dimensional ideological-bias and content-quality measurement for each tweet. We then infer a ``media-bias chart'' of (bias, quality) coordinates for the media outlets by integrating the (bias, quality) measurements of the tweets of the media outlets. We also apply a variety of baseline machine-learning methods, such as a naive-Bayes method and a support-vector machine (SVM), to infer the bias and quality values for each tweet. All of these baseline approaches are based on a bag-of-words approach. We find that the LSTM-network approach has the best performance of the examined methods. Our results illustrate the importance of leveraging word order into machine-learning methods in text analysis.
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Actively monitoring machine learning models during production operations helps ensure prediction quality and detection and remediation of unexpected or undesired conditions. Monitoring models already deployed in big data environments brings the additional challenges of adding monitoring in parallel to the existing modelling workflow and controlling resource requirements. In this paper, we describe (1) a framework for monitoring machine learning models; and, (2) its implementation for a big data supply chain application. We use our implementation to study drift in model features, predictions, and performance on three real data sets. We compare hypothesis test and information theoretic approaches to drift detection in features and predictions using the Kolmogorov-Smirnov distance and Bhattacharyya coefficient. Results showed that model performance was stable over the evaluation period. Features and predictions showed statistically significant drifts; however, these drifts were not linked to changes in model performance during the time of our study.
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Although prediction models for delirium, a commonly occurring condition during general hospitalization or post-surgery, have not gained huge popularity, their algorithmic bias evaluation is crucial due to the existing association between social determinants of health and delirium risk. In this context, using MIMIC-III and another academic hospital dataset, we present some initial experimental evidence showing how sociodemographic features such as sex and race can impact the model performance across subgroups. With this work, our intent is to initiate a discussion about the intersectionality effects of old age, race and socioeconomic factors on the early-stage detection and prevention of delirium using ML.
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Graph neural networks (GNNs) have received great attention due to their success in various graph-related learning tasks. Several GNN frameworks have then been developed for fast and easy implementation of GNN models. Despite their popularity, they are not well documented, and their implementations and system performance have not been well understood. In particular, unlike the traditional GNNs that are trained based on the entire graph in a full-batch manner, recent GNNs have been developed with different graph sampling techniques for mini-batch training of GNNs on large graphs. While they improve the scalability, their training times still depend on the implementations in the frameworks as sampling and its associated operations can introduce non-negligible overhead and computational cost. In addition, it is unknown how much the frameworks are 'eco-friendly' from a green computing perspective. In this paper, we provide an in-depth study of two mainstream GNN frameworks along with three state-of-the-art GNNs to analyze their performance in terms of runtime and power/energy consumption. We conduct extensive benchmark experiments at several different levels and present detailed analysis results and observations, which could be helpful for further improvement and optimization.
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Proteins play a central role in biology from immune recognition to brain activity. While major advances in machine learning have improved our ability to predict protein structure from sequence, determining protein function from structure remains a major challenge. Here, we introduce Holographic Convolutional Neural Network (H-CNN) for proteins, which is a physically motivated machine learning approach to model amino acid preferences in protein structures. H-CNN reflects physical interactions in a protein structure and recapitulates the functional information stored in evolutionary data. H-CNN accurately predicts the impact of mutations on protein function, including stability and binding of protein complexes. Our interpretable computational model for protein structure-function maps could guide design of novel proteins with desired function.
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套件是指准备和分组必要的零件和工具(或“套件”)以在制造环境中组装。自动化此过程可简化人工工人的组装任务,并提高效率。现有的自动化套件系统遵守脚本指示和预定义的启发式方法。但是,鉴于零件和逻辑延迟的可用性差异,现有系统的僵化性可以限制装配线的整体效率。在本文中,我们提出了一个双重优化框架,以使机器人能够执行基于任务分割的零件选择,套件布置和交付计划,以及时提供定制的套件 - 即在需要时正确。我们通过人类主题研究(n = 18)评估了提出的方法,涉及基于研究的数据构建平板家具桌和购物流仿真。我们的结果表明,与使用由任务图本身定义的刚性任务分割边界定义的基线方法相比,与基线方法相比,与基线方法相比,即将到来的套件系统更有效,对上游商店流量延迟有弹性,并且比较更好地优选。单个套件,包括组装单个单元所需的所有零件。
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美国的意识形态分裂在日常交流中变得越来越突出。因此,关于政治两极分化的许多研究,包括最近采取计算观点的许多努力。通过检测文本语料库中的政治偏见,可以尝试描述和辨别该文本的两极分性。从直觉上讲,命名的实体(即,用作名词的名词和短语)和文本中的标签经常带有有关政治观点的信息。例如,使用“支持选择”一词的人可能是自由的,而使用“亲生生命”一词的人可能是保守的。在本文中,我们试图揭示社交媒体文本数据中的政治极性,并通过将极性得分分配给实体和标签来量化这些极性。尽管这个想法很简单,但很难以可信赖的定量方式进行这种推论。关键挑战包括少数已知标签,连续的政治观点,以及在嵌入单词媒介中的极性得分和极性中性语义含义的保存。为了克服这些挑战,我们提出了极性感知的嵌入多任务学习(PEM)模型。该模型包括(1)自制的上下文保护任务,(2)基于注意力的推文级别的极性推导任务,以及(3)对抗性学习任务,可促进嵌入式的极性维度及其语义之间的独立性方面。我们的实验结果表明,我们的PEM模型可以成功学习极性感知的嵌入。我们检查了各种应用,从而证明了PEM模型的有效性。我们还讨论了我们的工作的重要局限性,并在将PEM模型应用于现实世界情景时的压力谨慎。
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