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。
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最近,致力于通过现代机器学习方法预测脑部疾病的最新神经影像学研究通常包括单一模态并依靠监督的过度参数化模型。但是,单一模态仅提供了高度复杂的大脑的有限视图。至关重要的是,临床环境中的有监督模型缺乏用于培训的准确诊断标签。粗标签不会捕获脑疾病表型的长尾谱,这导致模型的普遍性丧失,从而使它们在诊断环境中的有用程度降低。这项工作提出了一个新型的多尺度协调框架,用于从多模式神经影像数据中学习多个表示。我们提出了一般的归纳偏见分类法,以捕获多模式自学融合中的独特和联合信息。分类法构成了一个无解码器模型的家族,具有降低的计算复杂性,并捕获多模式输入的本地和全局表示之间的多尺度关系。我们使用各种阿尔茨海默氏病表型中使用功能和结构磁共振成像(MRI)数据对分类法进行了全面评估,并表明自我监督模型揭示了与疾病相关的大脑区域和多模态链接,而无需在预先访问PRE-PRE-the PRE-the PRE-the PRE-the PRE-PRECTEN NICKES NOCKER NOCKER NOCKER NOCKER NOCKER NOCE访问。训练。拟议的多模式自学学习的学习能够表现出两种模式的分类表现。伴随的丰富而灵活的无监督的深度学习框架捕获了复杂的多模式关系,并提供了符合或超过更狭窄的监督分类分析的预测性能。我们提供了详尽的定量证据,表明该框架如何显着提高我们对复杂脑部疾病中缺失的联系的搜索。
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在我们最近在加纳被动饮食监测的饮食评估现场研究中,我们收集了超过25万件野外图像。该数据集是一种持续的努力,旨在通过被动监控摄像头技术在低收入和中等收入国家中准确测量单个食物和营养摄入量。目前的数据集涉及加纳农村地区和城市地区的20个家庭(74个受试者),研究中使用了两种不同类型的可穿戴摄像机。一旦开始,可穿戴摄像机会不断捕获受试者的活动,该活动会产生大量的数据,以便在进行分析之前清洁和注释。为了简化数据后处理和注释任务,我们提出了一个新颖的自学学习框架,以将大量以自我为中心的图像聚集到单独的事件中。每个事件都由一系列时间连续和上下文相似的图像组成。通过将图像聚集到单独的事件中,注释者和营养师可以更有效地检查和分析数据,并促进随后的饮食评估过程。在带有地面真实标签的固定测试套装上验证,拟议的框架在聚集质量和分类准确性方面优于基准。
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肌肉骨骼和神经系统疾病是老年人行走问题的最常见原因,它们通常导致生活质量降低。分析步行运动数据手动需要训练有素的专业人员,并且评估可能并不总是客观的。为了促进早期诊断,最近基于深度学习的方法显示了自动分析的有希望的结果,这些方法可以发现传统的机器学习方法中未发现的模式。我们观察到,现有工作主要应用于单个联合特征,例如时间序列的联合职位。由于发现了诸如通常较小规模的医疗数据集的脚之间的距离(即步幅宽度)之类的挑战,因此这些方法通常是优选的。结果,我们提出了一种解决方案,该解决方案明确地将单个关节特征和关节间特征作为输入,从而使系统免于从小数据中发现更复杂的功能。由于两种特征的独特性质,我们引入了一个两流框架,其中一个流从关节位置的时间序列中学习,另一个从相对关节位移的时间序列中学习。我们进一步开发了一个中层融合模块,以将发现的两个流中发现的模式结合起来进行诊断,从而导致数据互补表示,以获得更好的预测性能。我们使用3D骨架运动的基准数据集涉及45例肌肉骨骼和神经系统疾病的患者,并实现95.56%的预测准确性,效果优于最先进的方法,从而验证了我们的系统。
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心血管疾病(CVD)是全球死亡的第一大原因。尽管有越来越多的证据表明心房颤动(AF)与各种CVD有着密切的关联,但这种心律不齐通常是使用心电图(ECG)诊断的,这是一种无风险,无侵入性和具有成本效益的工具。在任何威胁生命的疾病/疾病发展之前,不断和远程监视受试者的心电图信息迅速诊断和及时对AF进行预处理的潜力。最终,可以降低CVD相关的死亡率。在此手稿中,展示了体现可穿戴心电图设备,移动应用程序和后端服务器的个性化医疗系统的设计和实施。该系统不断监视用户的心电图信息,以提供个性化的健康警告/反馈。用户能够通过该系统与他们的配对健康顾问进行远程诊断,干预措施等。已经评估了实施的可穿戴ECG设备,并显示出极好的一致性(CVRMS = 5.5%),可接受的一致性(CVRMS = CVRMS = CVRMS = 12.1%),可忽略不计的RR间隙错误(<1.4%)。为了提高可穿戴设备的电池寿命,提出了使用ECG信号的准周期特征来实现压缩的有损压缩模式。与公认的架构相比,它在压缩效率和失真方面优于其他模式,并在MIT-BIH数据库中以ECG信号的某个PRD或RMSE达到了至少2倍的Cr。为了在拟议系统中实现自动化AF诊断/筛查,开发了基于重新系统的AF检测器。对于2017年Physionet CINC挑战的ECG记录,该AF探测器获得了平均测试F1 = 85.10%和最佳测试F1 = 87.31%,表现优于最先进。
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人重新识别(人REID)模型的现有评估指标着重于系统范围的性能。但是,我们的研究揭示了由于摄像机之间的数据分布不平的弱点和将REID系统暴露于剥削的不同摄像头性能。在这项工作中,我们提出了长期以来的摄像机性能不平衡问题,并从38个摄像机中收集了现实世界中的隐私意识数据集,以帮助研究不平衡问题。我们提出了新的指标来量化摄像机性能不平衡,并进一步提出了对抗性成对的反向关注(APRA)模块,以指导模型学习摄像机不变特征,并具有新颖的成对注意反转机制。
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We propose a conceptually simple and lightweight framework for deep reinforcement learning that uses asynchronous gradient descent for optimization of deep neural network controllers. We present asynchronous variants of four standard reinforcement learning algorithms and show that parallel actor-learners have a stabilizing effect on training allowing all four methods to successfully train neural network controllers. The best performing method, an asynchronous variant of actor-critic, surpasses the current state-of-the-art on the Atari domain while training for half the time on a single multi-core CPU instead of a GPU. Furthermore, we show that asynchronous actor-critic succeeds on a wide variety of continuous motor control problems as well as on a new task of navigating random 3D mazes using a visual input.
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Accurate determination of a small molecule candidate (ligand) binding pose in its target protein pocket is important for computer-aided drug discovery. Typical rigid-body docking methods ignore the pocket flexibility of protein, while the more accurate pose generation using molecular dynamics is hindered by slow protein dynamics. We develop a tiered tensor transform (3T) algorithm to rapidly generate diverse protein-ligand complex conformations for both pose and affinity estimation in drug screening, requiring neither machine learning training nor lengthy dynamics computation, while maintaining both coarse-grain-like coordinated protein dynamics and atomistic-level details of the complex pocket. The 3T conformation structures we generate are closer to experimental co-crystal structures than those generated by docking software, and more importantly achieve significantly higher accuracy in active ligand classification than traditional ensemble docking using hundreds of experimental protein conformations. 3T structure transformation is decoupled from the system physics, making future usage in other computational scientific domains possible.
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Variational autoencoders model high-dimensional data by positing low-dimensional latent variables that are mapped through a flexible distribution parametrized by a neural network. Unfortunately, variational autoencoders often suffer from posterior collapse: the posterior of the latent variables is equal to its prior, rendering the variational autoencoder useless as a means to produce meaningful representations. Existing approaches to posterior collapse often attribute it to the use of neural networks or optimization issues due to variational approximation. In this paper, we consider posterior collapse as a problem of latent variable non-identifiability. We prove that the posterior collapses if and only if the latent variables are non-identifiable in the generative model. This fact implies that posterior collapse is not a phenomenon specific to the use of flexible distributions or approximate inference. Rather, it can occur in classical probabilistic models even with exact inference, which we also demonstrate. Based on these results, we propose a class of latent-identifiable variational autoencoders, deep generative models which enforce identifiability without sacrificing flexibility. This model class resolves the problem of latent variable non-identifiability by leveraging bijective Brenier maps and parameterizing them with input convex neural networks, without special variational inference objectives or optimization tricks. Across synthetic and real datasets, latent-identifiable variational autoencoders outperform existing methods in mitigating posterior collapse and providing meaningful representations of the data.
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We derive a set of causal deep neural networks whose architectures are a consequence of tensor (multilinear) factor analysis. Forward causal questions are addressed with a neural network architecture composed of causal capsules and a tensor transformer. The former estimate a set of latent variables that represent the causal factors, and the latter governs their interaction. Causal capsules and tensor transformers may be implemented using shallow autoencoders, but for a scalable architecture we employ block algebra and derive a deep neural network composed of a hierarchy of autoencoders. An interleaved kernel hierarchy preprocesses the data resulting in a hierarchy of kernel tensor factor models. Inverse causal questions are addressed with a neural network that implements multilinear projection and estimates the causes of effects. As an alternative to aggressive bottleneck dimension reduction or regularized regression that may camouflage an inherently underdetermined inverse problem, we prescribe modeling different aspects of the mechanism of data formation with piecewise tensor models whose multilinear projections are well-defined and produce multiple candidate solutions. Our forward and inverse neural network architectures are suitable for asynchronous parallel computation.
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