动态图形表示学习是具有广泛应用程序的重要任务。以前关于动态图形学习的方法通常对嘈杂的图形信息(如缺失或虚假连接)敏感,可以产生退化的性能和泛化。为了克服这一挑战,我们提出了一种基于变换器的动态图表学习方法,命名为动态图形变换器(DGT),带有空间 - 时间编码,以有效地学习图形拓扑并捕获隐式链接。为了提高泛化能力,我们介绍了两个补充自我监督的预训练任务,并表明共同优化了两种预训练任务,通过信息理论分析导致较小的贝叶斯错误率。我们还提出了一个时间联盟图形结构和目标 - 上下文节点采样策略,用于高效和可扩展的培训。与现实世界数据集的广泛实验说明了与几个最先进的基线相比,DGT呈现出优异的性能。
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尽管图表神经网络(GNNS)的最近成功,但大图上的培训GNN仍然具有挑战性。现有服务器的有限资源容量,图中节点之间的依赖关系以及由于集中存储和模型学习导致的隐私问题刺激了用于GNN训练的有效分布式算法的需要。然而,现有的分布式GNN训练方法强加过度的通信成本或妨碍其可扩展性的大存储器开销。为了克服这些问题,我们提出了一种名为$ \ text {{locally,正确的全球}} $(llcg)的通信有效的分布式GNN培训技术。为了减少通信和内存开销,LLCG中的每个本地计算机首先通过忽略不同机器之间的节点之间的依赖性在其本地数据上列出GNN,然后将本地训练的模型发送到服务器以获取周期性模型平均。但是,忽略节点依赖性可能导致显着的性能下降。要解决性能下降,我们建议在服务器上应用$ \ text {{{global server校正}} $以优化本地学习的模型。我们严格地分析了具有用于训练GNN的周期性模型的分布式方法的收敛性,并且显示了天真地应用周期模型平均但忽略节点之间的依赖性将受到不可缩小的残余错误。然而,通过利用所提出的全局校正来避免收敛速度,可以消除这种剩余误差。对现实世界数据集的广泛实验表明,LLCG可以显着提高效率而不会伤害性能。
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图表卷积网络(GCNS)在各种半监督节点分类任务中取得了令人印象深刻的实证进步。尽管取得了巨大的成功,但在大型图形上培训GCNS遭受了计算和内存问题。规避这些障碍的潜在路径是基于采样的方法,其中在每个层处采样节点的子集。虽然最近的研究已经证明了基于采样的方法的有效性,但这些作品缺乏在现实环境下的理论融合担保,并且不能完全利用优化期间演出参数的信息。在本文中,我们描述并分析了一般的双差异减少模式,可以在内存预算下加速任何采样方法。所提出的模式的激励推动是仔细分析采样方法的差异,其中示出了诱导方差可以在前进传播期间分解为节点嵌入近似方差(Zeroth阶差异)(第一 - 顺序变化)在后向传播期间。理论上,从理论上分析所提出的架构的融合,并显示它享有$ \ Mathcal {O}(1 / T)$收敛率。我们通过将建议的模式集成在不同的采样方法中并将其应用于不同的大型实际图形来补充我们的理论结果。
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Large language models (LLMs) have demonstrated impressive capabilities in natural language understanding and generation, but the quality bar for medical and clinical applications is high. Today, attempts to assess models' clinical knowledge typically rely on automated evaluations on limited benchmarks. There is no standard to evaluate model predictions and reasoning across a breadth of tasks. To address this, we present MultiMedQA, a benchmark combining six existing open question answering datasets spanning professional medical exams, research, and consumer queries; and HealthSearchQA, a new free-response dataset of medical questions searched online. We propose a framework for human evaluation of model answers along multiple axes including factuality, precision, possible harm, and bias. In addition, we evaluate PaLM (a 540-billion parameter LLM) and its instruction-tuned variant, Flan-PaLM, on MultiMedQA. Using a combination of prompting strategies, Flan-PaLM achieves state-of-the-art accuracy on every MultiMedQA multiple-choice dataset (MedQA, MedMCQA, PubMedQA, MMLU clinical topics), including 67.6% accuracy on MedQA (US Medical License Exam questions), surpassing prior state-of-the-art by over 17%. However, human evaluation reveals key gaps in Flan-PaLM responses. To resolve this we introduce instruction prompt tuning, a parameter-efficient approach for aligning LLMs to new domains using a few exemplars. The resulting model, Med-PaLM, performs encouragingly, but remains inferior to clinicians. We show that comprehension, recall of knowledge, and medical reasoning improve with model scale and instruction prompt tuning, suggesting the potential utility of LLMs in medicine. Our human evaluations reveal important limitations of today's models, reinforcing the importance of both evaluation frameworks and method development in creating safe, helpful LLM models for clinical applications.
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From smoothly pursuing moving objects to rapidly shifting gazes during visual search, humans employ a wide variety of eye movement strategies in different contexts. While eye movements provide a rich window into mental processes, building generative models of eye movements is notoriously difficult, and to date the computational objectives guiding eye movements remain largely a mystery. In this work, we tackled these problems in the context of a canonical spatial planning task, maze-solving. We collected eye movement data from human subjects and built deep generative models of eye movements using a novel differentiable architecture for gaze fixations and gaze shifts. We found that human eye movements are best predicted by a model that is optimized not to perform the task as efficiently as possible but instead to run an internal simulation of an object traversing the maze. This not only provides a generative model of eye movements in this task but also suggests a computational theory for how humans solve the task, namely that humans use mental simulation.
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The outburst of COVID-19 in late 2019 was the start of a health crisis that shook the world and took millions of lives in the ensuing years. Many governments and health officials failed to arrest the rapid circulation of infection in their communities. The long incubation period and the large proportion of asymptomatic cases made COVID-19 particularly elusive to track. However, wastewater monitoring soon became a promising data source in addition to conventional indicators such as confirmed daily cases, hospitalizations, and deaths. Despite the consensus on the effectiveness of wastewater viral load data, there is a lack of methodological approaches that leverage viral load to improve COVID-19 forecasting. This paper proposes using deep learning to automatically discover the relationship between daily confirmed cases and viral load data. We trained one Deep Temporal Convolutional Networks (DeepTCN) and one Temporal Fusion Transformer (TFT) model to build a global forecasting model. We supplement the daily confirmed cases with viral loads and other socio-economic factors as covariates to the models. Our results suggest that TFT outperforms DeepTCN and learns a better association between viral load and daily cases. We demonstrated that equipping the models with the viral load improves their forecasting performance significantly. Moreover, viral load is shown to be the second most predictive input, following the containment and health index. Our results reveal the feasibility of training a location-agnostic deep-learning model to capture the dynamics of infection diffusion when wastewater viral load data is provided.
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Single-cell sequencing assay for transposase-accessible chromatin (scATAC-seq) assesses genome-wide chromatin accessibility in thousands of cells to reveal regulatory landscapes in high resolutions. However, the analysis presents challenges due to the high dimensionality and sparsity of the data. Several methods have been developed, including transformation techniques of term-frequency inverse-document frequency (TF-IDF), dimension reduction methods such as singular value decomposition (SVD), factor analysis, and autoencoders. Yet, a comprehensive study on the mentioned methods has not been fully performed. It is not clear what is the best practice when analyzing scATAC-seq data. We compared several scenarios for transformation and dimension reduction as well as the SVD-based feature analysis to investigate potential enhancements in scATAC-seq information retrieval. Additionally, we investigate if autoencoders benefit from the TF-IDF transformation. Our results reveal that the TF-IDF transformation generally leads to improved clustering and biologically relevant feature extraction.
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This work concerns developing communication- and computation-efficient methods for large-scale multiple testing over networks, which is of interest to many practical applications. We take an asymptotic approach and propose two methods, proportion-matching and greedy aggregation, tailored to distributed settings. The proportion-matching method achieves the global BH performance yet only requires a one-shot communication of the (estimated) proportion of true null hypotheses as well as the number of p-values at each node. By focusing on the asymptotic optimal power, we go beyond the BH procedure by providing an explicit characterization of the asymptotic optimal solution. This leads to the greedy aggregation method that effectively approximate the optimal rejection regions at each node, while computation-efficiency comes from the greedy-type approach naturally. Extensive numerical results over a variety of challenging settings are provided to support our theoretical findings.
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当网络条件恶化时,视频会议系统的用户体验差,因为当前的视频编解码器根本无法在极低的比特率下运行。最近,已经提出了几种神经替代方案,可以使用每个框架的稀疏表示,例如面部地标信息,以非常低的比特率重建说话的头视频。但是,这些方法在通话过程中具有重大运动或遮挡的情况下会产生不良的重建,并且不会扩展到更高的分辨率。我们设计了Gemino,这是一种基于新型高频条件超分辨率管道的新型神经压缩系统,用于视频会议。 Gemino根据从单个高分辨率参考图像中提取的信息来增强高频细节(例如,皮肤纹理,头发等),为每个目标框架的一个非常低分辨率的版本(例如,皮肤纹理,头发等)。我们使用多尺度体系结构,该体系结构在不同的分辨率下运行模型的不同组件,从而使其扩展到可与720p相当的分辨率,并且我们个性化模型以学习每个人的特定细节,在低比特率上实现了更好的保真度。我们在AIORTC上实施了Gemino,这是WEBRTC的开源Python实现,并表明它在A100 GPU上实时在1024x1024视频上运行,比比特率的比特率低于传统的视频Codecs,以相同的感知质量。
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kronecker回归是一个高度结构的最小二乘问题$ \ min _ {\ mathbf {x}}} \ lvert \ mathbf {k} \ mathbf {x} - \ mathbf {b} \ rvert_ \ rvert_ {2}^2 $矩阵$ \ mathbf {k} = \ mathbf {a}^{(1)} \ otimes \ cdots \ cdots \ otimes \ mathbf {a}^{(n)} $是因子矩阵的Kronecker产品。这种回归问题是在广泛使用的最小二乘(ALS)算法的每个步骤中都出现的,用于计算张量的塔克分解。我们介绍了第一个用于求解Kronecker回归的子次数算法,以避免在运行时间中避免指数项$ o(\ varepsilon^{ - n})$的$(1+ \ varepsilon)$。我们的技术结合了利用分数抽样和迭代方法。通过扩展我们对一个块是Kronecker产品的块设计矩阵的方法,我们还实现了(1)Kronecker Ridge回归的亚次级时间算法,并且(2)更新ALS中Tucker分解的因子矩阵,这不是一个不是一个纯Kronecker回归问题,从而改善了Tucker ALS的所有步骤的运行时间。我们证明了该Kronecker回归算法在合成数据和现实世界图像张量上的速度和准确性。
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