在许多情况下,更简单的模型比更复杂的模型更可取,并且该模型复杂性的控制是机器学习中许多方法的目标,例如正则化,高参数调整和体系结构设计。在深度学习中,很难理解复杂性控制的潜在机制,因为许多传统措施并不适合深度神经网络。在这里,我们开发了几何复杂性的概念,该概念是使用离散的dirichlet能量计算的模型函数变异性的量度。使用理论论据和经验结果的结合,我们表明,许多常见的训练启发式方法,例如参数规范正规化,光谱规范正则化,平稳性正则化,隐式梯度正则化,噪声正则化和参数初始化的选择,都可以控制几何学复杂性,并提供一个统一的框架,以表征深度学习模型的行为。
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在过度参数化的深度神经网络中,可能有许多可能的参数配置,可以完全适合训练数据。然而,这些内插解决方案的性质理解得很差。我们认为,随机梯度血淋于训练的过度参数化神经网络受几何偶数的剃刀;也就是说,通过几何模型复杂性隐式规范这些网络。对于一维回归,几何模型复杂性仅由函数的电弧长度给出。对于高维设置,几何模型复杂性取决于功能的Dirichlet能量。我们探讨了这种几何偶数剃须刀,Dirichlet能量和其他已知形式的隐式正则化的关系。最后,对于在CiFar-10上培训的Resnets,我们观察到Dirichlet Energy测量与这种隐式几何偶数剃刀的动作一致。
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梯度下降可能令人惊讶地擅长优化深层神经网络,而不会过度拟合并且没有明确的正则化。我们发现,梯度下降的离散步骤通过惩罚具有较大损耗梯度的梯度下降轨迹来隐式化模型。我们称之为隐式梯度正则化(IGR),并使用向后错误分析来计算此正则化的大小。我们从经验上确认,隐式梯度正则化偏向梯度下降到平面最小值,在该较小情况下,测试误差很小,溶液对嘈杂的参数扰动是可靠的。此外,我们证明了隐式梯度正规化项可以用作显式正常化程序,从而使我们能够直接控制此梯度正则化。从更广泛的角度来看,我们的工作表明,向后错误分析是一种有用的理论方法,即对学习率,模型大小和参数正则化如何相互作用以确定用梯度下降优化的过度参数化模型的属性。
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Relational reasoning is a central component of generally intelligent behavior, but has proven difficult for neural networks to learn. In this paper we describe how to use Relation Networks (RNs) as a simple plug-and-play module to solve problems that fundamentally hinge on relational reasoning. We tested RN-augmented networks on three tasks: visual question answering using a challenging dataset called CLEVR, on which we achieve state-of-the-art, super-human performance; text-based question answering using the bAbI suite of tasks; and complex reasoning about dynamic physical systems. Then, using a curated dataset called Sort-of-CLEVR we show that powerful convolutional networks do not have a general capacity to solve relational questions, but can gain this capacity when augmented with RNs. Our work shows how a deep learning architecture equipped with an RN module can implicitly discover and learn to reason about entities and their relations.
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To analyze this characteristic of vulnerability, we developed an automated deep learning method for detecting microvessels in intravascular optical coherence tomography (IVOCT) images. A total of 8,403 IVOCT image frames from 85 lesions and 37 normal segments were analyzed. Manual annotation was done using a dedicated software (OCTOPUS) previously developed by our group. Data augmentation in the polar (r,{\theta}) domain was applied to raw IVOCT images to ensure that microvessels appear at all possible angles. Pre-processing methods included guidewire/shadow detection, lumen segmentation, pixel shifting, and noise reduction. DeepLab v3+ was used to segment microvessel candidates. A bounding box on each candidate was classified as either microvessel or non-microvessel using a shallow convolutional neural network. For better classification, we used data augmentation (i.e., angle rotation) on bounding boxes with a microvessel during network training. Data augmentation and pre-processing steps improved microvessel segmentation performance significantly, yielding a method with Dice of 0.71+/-0.10 and pixel-wise sensitivity/specificity of 87.7+/-6.6%/99.8+/-0.1%. The network for classifying microvessels from candidates performed exceptionally well, with sensitivity of 99.5+/-0.3%, specificity of 98.8+/-1.0%, and accuracy of 99.1+/-0.5%. The classification step eliminated the majority of residual false positives, and the Dice coefficient increased from 0.71 to 0.73. In addition, our method produced 698 image frames with microvessels present, compared to 730 from manual analysis, representing a 4.4% difference. When compared to the manual method, the automated method improved microvessel continuity, implying improved segmentation performance. The method will be useful for research purposes as well as potential future treatment planning.
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Thin-cap fibroatheroma (TCFA) and plaque rupture have been recognized as the most frequent risk factor for thrombosis and acute coronary syndrome. Intravascular optical coherence tomography (IVOCT) can identify TCFA and assess cap thickness, which provides an opportunity to assess plaque vulnerability. We developed an automated method that can detect lipidous plaque and assess fibrous cap thickness in IVOCT images. This study analyzed a total of 4,360 IVOCT image frames of 77 lesions among 41 patients. To improve segmentation performance, preprocessing included lumen segmentation, pixel-shifting, and noise filtering on the raw polar (r, theta) IVOCT images. We used the DeepLab-v3 plus deep learning model to classify lipidous plaque pixels. After lipid detection, we automatically detected the outer border of the fibrous cap using a special dynamic programming algorithm and assessed the cap thickness. Our method provided excellent discriminability of lipid plaque with a sensitivity of 85.8% and A-line Dice coefficient of 0.837. By comparing lipid angle measurements between two analysts following editing of our automated software, we found good agreement by Bland-Altman analysis (difference 6.7+/-17 degree; mean 196 degree). Our method accurately detected the fibrous cap from the detected lipid plaque. Automated analysis required a significant modification for only 5.5% frames. Furthermore, our method showed a good agreement of fibrous cap thickness between two analysts with Bland-Altman analysis (4.2+/-14.6 micron; mean 175 micron), indicating little bias between users and good reproducibility of the measurement. We developed a fully automated method for fibrous cap quantification in IVOCT images, resulting in good agreement with determinations by analysts. The method has great potential to enable highly automated, repeatable, and comprehensive evaluations of TCFAs.
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制定了具有机器学习模拟(骆驼)项目的宇宙学和天体物理学,通过数千名宇宙的流体动力模拟和机器学习将宇宙学与天体物理学结合起来。骆驼包含4,233个宇宙学仿真,2,049个n-body和2,184个最先进的流体动力模拟,在参数空间中采样巨大的体积。在本文中,我们介绍了骆驼公共数据发布,描述了骆驼模拟的特性和由它们产生的各种数据产品,包括光环,次麦,银河系和空隙目录,功率谱,Bispectra,Lyman - $ \ Alpha $光谱,概率分布函数,光环径向轮廓和X射线光子列表。我们还释放了超过骆驼 - 山姆的数十亿个星系的目录:与Santa Cruz半分析模型相结合的大量N身体模拟。我们释放包含350多个Terabytes的所有数据,并包含143,922个快照,数百万光环,星系和摘要统计数据。我们提供有关如何访问,下载,读取和处理数据AT \ URL {https://camels.readthedocs.io}的进一步技术详细信息。
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超越地球轨道的人类空间勘探将涉及大量距离和持续时间的任务。为了有效减轻无数空间健康危害,数据和空间健康系统的范式转移是实现地球独立性的,而不是Earth-Reliance所必需的。有希望在生物学和健康的人工智能和机器学习领域的发展可以解决这些需求。我们提出了一个适当的自主和智能精密空间健康系统,可以监控,汇总和评估生物医学状态;分析和预测个性化不良健康结果;适应并响应新累积的数据;并提供对其船员医务人员的个人深度空间机组人员和迭代决策支持的预防性,可操作和及时的见解。在这里,我们介绍了美国国家航空航天局组织的研讨会的建议摘要,以便在太空生物学和健康中未来的人工智能应用。在未来十年,生物监测技术,生物标志科学,航天器硬件,智能软件和简化的数据管理必须成熟,并编织成精确的空间健康系统,以使人类在深空中茁壮成长。
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空间生物学研究旨在了解太空飞行对生物的根本影响,制定支持深度空间探索的基础知识,最终生物工程航天器和栖息地稳定植物,农作物,微生物,动物和人类的生态系统,为持续的多行星寿命稳定。要提高这些目标,该领域利用了来自星空和地下模拟研究的实验,平台,数据和模型生物。由于研究扩展到低地球轨道之外,实验和平台必须是最大自主,光,敏捷和智能化,以加快知识发现。在这里,我们介绍了由美国国家航空航天局的人工智能,机器学习和建模应用程序组织的研讨会的建议摘要,这些应用程序为这些空间生物学挑战提供了关键解决方案。在未来十年中,将人工智能融入太空生物学领域将深化天空效应的生物学理解,促进预测性建模和分析,支持最大自主和可重复的实验,并有效地管理星载数据和元数据,所有目标使生活能够在深空中茁壮成长。
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放射线学使用定量医学成像特征来预测临床结果。目前,在新的临床应用中,必须通过启发式试验和纠正过程手动完成各种可用选项的最佳放射组方法。在这项研究中,我们提出了一个框架,以自动优化每个应用程序的放射线工作流程的构建。为此,我们将放射线学作为模块化工作流程,并为每个组件包含大量的常见算法。为了优化每个应用程序的工作流程,我们使用随机搜索和结合使用自动化机器学习。我们在十二个不同的临床应用中评估我们的方法,从而在曲线下导致以下区域:1)脂肪肉瘤(0.83); 2)脱粘型纤维瘤病(0.82); 3)原发性肝肿瘤(0.80); 4)胃肠道肿瘤(0.77); 5)结直肠肝转移(0.61); 6)黑色素瘤转移(0.45); 7)肝细胞癌(0.75); 8)肠系膜纤维化(0.80); 9)前列腺癌(0.72); 10)神经胶质瘤(0.71); 11)阿尔茨海默氏病(0.87);和12)头颈癌(0.84)。我们表明,我们的框架具有比较人类专家的竞争性能,优于放射线基线,并且表现相似或优于贝叶斯优化和更高级的合奏方法。最后,我们的方法完全自动优化了放射线工作流的构建,从而简化了在新应用程序中对放射线生物标志物的搜索。为了促进可重复性和未来的研究,我们公开发布了六个数据集,框架的软件实施以及重现这项研究的代码。
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