频谱图分类在分析引力波数据中起重要作用。在本文中，我们提出了一个框架来通过使用生成对抗网络（GAN）来改善分类性能。由于注释光谱图需要大量的努力和专业知识，因此训练示例的数量非常有限。但是，众所周知，只有当训练集的样本量足够大时，深层网络才能表现良好。此外，不同类别中的样本数量不平衡也会阻碍性能。为了解决这些问题，我们提出了一个基于GAN的数据增强框架。虽然无法在频谱图上应用常规图像的标准数据增强方法，但我们发现，甘恩（Progan）的一种变体能够生成高分辨率频谱图，这些光谱图与高分辨率原始图像的质量一致并提供了理想的多样性。我们通过将{\ it Gravity间谍}数据集中的小故障与GAN生成的频谱图分类为训练，从而验证了我们的框架。我们表明，所提出的方法可以为使用深网的分类提供转移学习的替代方法，即使用高分辨率GAN进行数据增强。此外，可以大大降低分类性能的波动，用于训练和评估的小样本量。在我们的框架中，使用训练有素的网络，我们还检查了{\ it Gravity Spy}中标签异常的频谱图。

背景：12个引线ECG是心血管疾病的核心诊断工具。在这里，我们描述并分析了一个集成的深度神经网络架构，从12个引导eCG分类了24个心脏异常。方法：我们提出了挤压和激发reset，以自动学习来自12个引主ECG的深度特征，以识别24个心脏病。在最终完全连接的层中，随着年龄和性别特征增强了深度特征。使用约束网格搜索设置每个类的输出阈值。为了确定为什么该模型的预测不正确，两个专家诊所人员独立地解释了一组关于左轴偏差的一次无序的ECG。结果：采用定制加权精度度量，我们达到了0.684的5倍交叉验证得分，灵敏度和特异性分别为0.758和0.969。我们在完整的测试数据中得分0.520，并在官方挑战排名中排名第21中。在一系列被错误分类的心电图中，两个临床医生和训练标签之间的协议差（临床医生1：Kappa = -0.057，临床医生2：Kappa = -0.159）。相比之下，临床医生之间的协议非常高（Kappa = 0.92）。讨论：与在相同数据上培训的模型相比，所提出的预测模型很好地对验证和隐藏的测试数据进行了良好。我们还发现培训标签的相当不一致，这可能会阻碍更准确的模型的开发。

一个多世纪以前，伊万·P·帕夫洛夫（Ivan P. Pavlov）在经典实验中展示了狗如何学会将铃铛与食物联系起来，从而导致戒指导致唾液。如今，很少发现使用Pavlovian类型的关联学习用于人工智能（AI）应用程序，即使其他学习概念，尤其是对人工神经网络（ANN）的反向传播也蓬勃发展。但是，使用反向传播方法的训练在“常规” ANN上，尤其是现代深神经网络（DNNS）的形式，是计算和能量密集型的。在这里，我们在实验上展示了使用单个（或单一）关联硬件元素的无反向传播学习形式。我们使用相位变换材料与芯片级联方向耦合器相结合的集成光子平台上意识到这一点。然后，我们使用我们的Monadic Pavlovian光子硬件开发扩展的电路网络，该硬件可以基于单元素关联提供独特的机器学习框架，并且重要的是，重要的是，使用无反向传播的架构来解决一般学习任务。我们的方法通过在传统的神经网络方法中学习来减轻施加的计算负担，从而提高了速度，同时还提供了我们光子实现固有的更高带宽。

Springs are efficient in storing and returning elastic potential energy but are unable to hold the energy they store in the absence of an external load. Lockable springs use clutches to hold elastic potential energy in the absence of an external load but have not yet been widely adopted in applications, partly because clutches introduce design complexity, reduce energy efficiency, and typically do not afford high-fidelity control over the energy stored by the spring. Here, we present the design of a novel lockable compression spring that uses a small capstan clutch to passively lock a mechanical spring. The capstan clutch can lock up to 1000 N force at any arbitrary deflection, unlock the spring in less than 10 ms with a control force less than 1 % of the maximal spring force, and provide an 80 % energy storage and return efficiency (comparable to a highly efficient electric motor operated at constant nominal speed). By retaining the form factor of a regular spring while providing high-fidelity locking capability even under large spring forces, the proposed design could facilitate the development of energy-efficient spring-based actuators and robots.

Traditionally, data analysis and theory have been viewed as separate disciplines, each feeding into fundamentally different types of models. Modern deep learning technology is beginning to unify these two disciplines and will produce a new class of predictively powerful space weather models that combine the physical insights gained by data and theory. We call on NASA to invest in the research and infrastructure necessary for the heliophysics' community to take advantage of these advances.

In the Earth's magnetosphere, there are fewer than a dozen dedicated probes beyond low-Earth orbit making in-situ observations at any given time. As a result, we poorly understand its global structure and evolution, the mechanisms of its main activity processes, magnetic storms, and substorms. New Artificial Intelligence (AI) methods, including machine learning, data mining, and data assimilation, as well as new AI-enabled missions will need to be developed to meet this Sparse Data challenge.

Late-life depression (LLD) is a highly prevalent mood disorder occurring in older adults and is frequently accompanied by cognitive impairment (CI). Studies have shown that LLD may increase the risk of Alzheimer's disease (AD). However, the heterogeneity of presentation of geriatric depression suggests that multiple biological mechanisms may underlie it. Current biological research on LLD progression incorporates machine learning that combines neuroimaging data with clinical observations. There are few studies on incident cognitive diagnostic outcomes in LLD based on structural MRI (sMRI). In this paper, we describe the development of a hybrid representation learning (HRL) framework for predicting cognitive diagnosis over 5 years based on T1-weighted sMRI data. Specifically, we first extract prediction-oriented MRI features via a deep neural network, and then integrate them with handcrafted MRI features via a Transformer encoder for cognitive diagnosis prediction. Two tasks are investigated in this work, including (1) identifying cognitively normal subjects with LLD and never-depressed older healthy subjects, and (2) identifying LLD subjects who developed CI (or even AD) and those who stayed cognitively normal over five years. To the best of our knowledge, this is among the first attempts to study the complex heterogeneous progression of LLD based on task-oriented and handcrafted MRI features. We validate the proposed HRL on 294 subjects with T1-weighted MRIs from two clinically harmonized studies. Experimental results suggest that the HRL outperforms several classical machine learning and state-of-the-art deep learning methods in LLD identification and prediction tasks.

We present a machine-learning framework to accurately characterize morphologies of Active Galactic Nucleus (AGN) host galaxies within $z<1$. We first use PSFGAN to decouple host galaxy light from the central point source, then we invoke the Galaxy Morphology Network (GaMorNet) to estimate whether the host galaxy is disk-dominated, bulge-dominated, or indeterminate. Using optical images from five bands of the HSC Wide Survey, we build models independently in three redshift bins: low $(0<z<0.25)$, medium $(0.25<z<0.5)$, and high $(0.5<z<1.0)$. By first training on a large number of simulated galaxies, then fine-tuning using far fewer classified real galaxies, our framework predicts the actual morphology for $\sim$ $60\%-70\%$ host galaxies from test sets, with a classification precision of $\sim$ $80\%-95\%$, depending on redshift bin. Specifically, our models achieve disk precision of $96\%/82\%/79\%$ and bulge precision of $90\%/90\%/80\%$ (for the 3 redshift bins), at thresholds corresponding to indeterminate fractions of $30\%/43\%/42\%$. The classification precision of our models has a noticeable dependency on host galaxy radius and magnitude. No strong dependency is observed on contrast ratio. Comparing classifications of real AGNs, our models agree well with traditional 2D fitting with GALFIT. The PSFGAN+GaMorNet framework does not depend on the choice of fitting functions or galaxy-related input parameters, runs orders of magnitude faster than GALFIT, and is easily generalizable via transfer learning, making it an ideal tool for studying AGN host galaxy morphology in forthcoming large imaging survey.

A long-standing goal of machine-learning-based protein engineering is to accelerate the discovery of novel mutations that improve the function of a known protein. We introduce a sampling framework for evolving proteins in silico that supports mixing and matching a variety of unsupervised models, such as protein language models, and supervised models that predict protein function from sequence. By composing these models, we aim to improve our ability to evaluate unseen mutations and constrain search to regions of sequence space likely to contain functional proteins. Our framework achieves this without any model fine-tuning or re-training by constructing a product of experts distribution directly in discrete protein space. Instead of resorting to brute force search or random sampling, which is typical of classic directed evolution, we introduce a fast MCMC sampler that uses gradients to propose promising mutations. We conduct in silico directed evolution experiments on wide fitness landscapes and across a range of different pre-trained unsupervised models, including a 650M parameter protein language model. Our results demonstrate an ability to efficiently discover variants with high evolutionary likelihood as well as estimated activity multiple mutations away from a wild type protein, suggesting our sampler provides a practical and effective new paradigm for machine-learning-based protein engineering.

Most previous unsupervised domain adaptation (UDA) methods for question answering(QA) require access to source domain data while fine-tuning the model for the target domain. Source domain data may, however, contain sensitive information and may be restricted. In this study, we investigate a more challenging setting, source-free UDA, in which we have only the pretrained source model and target domain data, without access to source domain data. We propose a novel self-training approach to QA models that integrates a unique mask module for domain adaptation. The mask is auto-adjusted to extract key domain knowledge while trained on the source domain. To maintain previously learned domain knowledge, certain mask weights are frozen during adaptation, while other weights are adjusted to mitigate domain shifts with pseudo-labeled samples generated in the target domain. %As part of the self-training process, we generate pseudo-labeled samples in the target domain based on models trained in the source domain. Our empirical results on four benchmark datasets suggest that our approach significantly enhances the performance of pretrained QA models on the target domain, and even outperforms models that have access to the source data during adaptation.