我们提出了一种新方法,即校准的非参数扫描统计量(CNSS),以更准确地检测大型现实世界图中的异常模式。扫描统计数据可以通过最大化似然比统计量来确定有趣或意外的连接子图;特别是,非参数扫描统计(NPSS)识别具有比预期的单独显着节点比例高的子图。但是,我们表明最近提出的NPSS方法被错误地校准了,无法解释统计量超过子图的多样性。这既可以降低微妙信号的检测能力,又导致检测到的子图的精度降低,即使对于更强的信号也是如此。因此,我们开发了一种重新校准NPSS的新统计方法,正确调整了多个假设测试并考虑了基础图结构。虽然基于随机测试的重新校准在计算上是昂贵的,但我们提出了一种有效的(近似)算法和新的,封闭形式的下限(在零假设下,在给定大小的子尺寸的显着节点的预期最大比例上,没有异常模式)。这些进步,加上最近的核心树分解方法的整合,使CNSS能够扩展到大型现实世界图,并在检测到的子学的准确性方面有了很大的提高。与最先进的对应物相比,证明了对半合成和现实数据集的广泛实验,以验证我们提出的方法的有效性。
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图形神经网络(GNNS)提供了一种强大而可扩展的解决方案,可用于建模连续空间数据。然而,在没有关于数据的几何结构上的进一步上下文的情况下,它们通常依赖于欧几里德距离来构造输入图。这种假设可以在许多现实世界的环境中不可能实现,其中空间结构更复杂,明确地非欧几里德(例如,道路网络)。在本文中,我们提出了PE-GNN,这是一个新的框架,该框架结合到模型中的空间上下文和相关性。建立在地理空间辅助任务学习和语义空间嵌入的最近进步,我们所提出的方法(1)学习地理坐标的上下文感知向量编码,(2)与主要任务并行地预测数据中的空间自相关。在空间回归任务中,我们展示了我们方法的有效性,提高了不同最先进的GNN方法的性能。我们还测试了我们的空间插值方法,即没有节点功能的空间回归,GNN目前不竞争的任务。我们观察到,我们的方法不仅大大改进了GNN基线,而且可以匹配高斯过程,是空间插值问题的最常用方法。
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Objective: Imbalances of the electrolyte concentration levels in the body can lead to catastrophic consequences, but accurate and accessible measurements could improve patient outcomes. While blood tests provide accurate measurements, they are invasive and the laboratory analysis can be slow or inaccessible. In contrast, an electrocardiogram (ECG) is a widely adopted tool which is quick and simple to acquire. However, the problem of estimating continuous electrolyte concentrations directly from ECGs is not well-studied. We therefore investigate if regression methods can be used for accurate ECG-based prediction of electrolyte concentrations. Methods: We explore the use of deep neural networks (DNNs) for this task. We analyze the regression performance across four electrolytes, utilizing a novel dataset containing over 290000 ECGs. For improved understanding, we also study the full spectrum from continuous predictions to binary classification of extreme concentration levels. To enhance clinical usefulness, we finally extend to a probabilistic regression approach and evaluate different uncertainty estimates. Results: We find that the performance varies significantly between different electrolytes, which is clinically justified in the interplay of electrolytes and their manifestation in the ECG. We also compare the regression accuracy with that of traditional machine learning models, demonstrating superior performance of DNNs. Conclusion: Discretization can lead to good classification performance, but does not help solve the original problem of predicting continuous concentration levels. While probabilistic regression demonstrates potential practical usefulness, the uncertainty estimates are not particularly well-calibrated. Significance: Our study is a first step towards accurate and reliable ECG-based prediction of electrolyte concentration levels.
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The COVID-19 pandemic created a deluge of questionable and contradictory scientific claims about drug efficacy -- an "infodemic" with lasting consequences for science and society. In this work, we argue that NLP models can help domain experts distill and understand the literature in this complex, high-stakes area. Our task is to automatically identify contradictory claims about COVID-19 drug efficacy. We frame this as a natural language inference problem and offer a new NLI dataset created by domain experts. The NLI framing allows us to create curricula combining existing datasets and our own. The resulting models are useful investigative tools. We provide a case study of how these models help a domain expert summarize and assess evidence concerning remdisivir and hydroxychloroquine.
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The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.
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Sampling diverse programs from a code language model and reranking with model likelihood is a popular method for code generation but it is prone to preferring degenerate solutions. Inspired by collaborative programming, we propose Coder-Reviewer reranking. We augment Coder language models from past work, which generate programs given language instructions, with Reviewer models, which evaluate the likelihood of the instruction given the generated programs. We perform an extensive study across six datasets with eight models from three model families. Experimental results show that Coder-Reviewer reranking leads to consistent and significant improvement (up to 17% absolute accuracy gain) over reranking with the Coder model only. When combined with executability filtering, Coder-Reviewer reranking can often outperform the minimum Bayes risk method. Coder-Reviewer reranking is easy to implement by prompting, can generalize to different programming languages, and works well with off-the-shelf hyperparameters.
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This paper presents a subsampling-task paradigm for data-driven task-specific experiment design (ED) and a novel method in populationwide supervised feature selection (FS). Optimal ED, the choice of sampling points under constraints of limited acquisition-time, arises in a wide variety of scientific and engineering contexts. However the continuous optimization used in classical approaches depend on a-priori parameter choices and challenging non-convex optimization landscapes. This paper proposes to replace this strategy with a subsampling-task paradigm, analogous to populationwide supervised FS. In particular, we introduce JOFSTO, which performs JOint Feature Selection and Task Optimization. JOFSTO jointly optimizes two coupled networks: one for feature scoring, which provides the ED, the other for execution of a downstream task or process. Unlike most FS problems, e.g. selecting protein expressions for classification, ED problems typically select from highly correlated globally informative candidates rather than seeking a small number of highly informative features among many uninformative features. JOFSTO's construction efficiently identifies potentially correlated, but effective subsets and returns a trained task network. We demonstrate the approach using parameter estimation and mapping problems in clinically-relevant applications in quantitative MRI and in hyperspectral imaging. Results from simulations and empirical data show the subsampling-task paradigm strongly outperforms classical ED, and within our paradigm, JOFSTO outperforms state-of-the-art supervised FS techniques. JOFSTO extends immediately to wider image-based ED problems and other scenarios where the design must be specified globally across large numbers of acquisitions. Code will be released.
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本文提出了一种延时3D细胞分析的方法。具体而言,我们考虑了准确定位和定量分析亚细胞特征的问题,以及从延时3D共聚焦细胞图像堆栈跟踪单个细胞的问题。细胞的异质性和多维图像的体积提出了对细胞形态发生和发育的完全自动化分析的主要挑战。本文是由路面细胞生长过程和构建定量形态发生模型的动机。我们提出了一种基于深度特征的分割方法,以准确检测和标记每个细胞区域。基于邻接图的方法用于提取分段细胞的亚细胞特征。最后,提出了使用多个单元格特征的基于强大的图形跟踪算法在不同的时间实例中关联单元格。提供了广泛的实验结果,并证明了所提出的方法的鲁棒性。该代码可在GitHub上获得,该方法可通过Bisque Portal作为服务可用。
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机器人模拟一直是机器人领域研发的组成部分。模拟消除了通过启用机器人的应用测试来快速,负担得起的,而无需遭受机械或电子误差而进行机器人应用测试,从而消除了对传感器,电动机和实际机器人物理结构的可能性。通过虚拟现实(VR)模拟,通过提供更好的环境可视化提示,为与模拟机器人互动提供了更具吸引力的替代方法,从而提供了更严肃的体验。这种沉浸至关重要,尤其是在讨论社交机器人时,人类机器人相互作用(HRI)领域的子区域。在日常生活中,机器人的广泛使用取决于HRI。将来,机器人将能够与人们有效互动,以在人类文明中执行各种任务。在个人工作空间开始扩散时,为机器人开发简单且易于理解的接口至关重要。因此,在这项研究中,我们实施了一个使用现成的工具和包装的VR机器人框架,以增强社交HRI的研究和应用开发。由于整个VR接口是一个开源项目,因此可以在身临其境的环境中进行测试,而无需物理机器人。
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人类能够在鲁棒性,多功能性和学习各种运动中的新任务方面超越机器人。我们假设高度非线性的肌肉动力学在提供固有的稳定性方面起着重要作用,这有利于学习。虽然在模拟和机器人技术中将现代学习技术应用于肌肉动态系统方面取得了最新进展,但到目前为止,尚未进行详细的分析以在这种情况下显示肌肉的好处。我们的研究通过研究核心机器人技术的挑战并比较不同执行器形态的性能,从数据效率,超参数灵敏度和鲁棒性进行比较。
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