部分微分方程(PDE)参见在科学和工程中的广泛使用,以将物理过程的模拟描述为标量和向量场随着时间的推移相互作用和协调。由于其标准解决方案方法的计算昂贵性质,神经PDE代理已成为加速这些模拟的积极研究主题。但是,当前的方法并未明确考虑不同字段及其内部组件之间的关系,这些关系通常是相关的。查看此类相关场的时间演变通过多活动场的镜头,使我们能够克服这些局限性。多胎场由标量,矢量以及高阶组成部分组成,例如双分数和三分分射线。 Clifford代数可以描述它们的代数特性,例如乘法,加法和其他算术操作。据我们所知,本文介绍了此类多人表示的首次使用以及Clifford的卷积和Clifford Fourier在深度学习的背景下的转换。由此产生的Clifford神经层普遍适用,并将在流体动力学,天气预报和一般物理系统的建模领域中直接使用。我们通过经验评估克利福德神经层的好处,通过在二维Navier-Stokes和天气建模任务以及三维Maxwell方程式上取代其Clifford对应物中常见的神经PDE代理中的卷积和傅立叶操作。克利福德神经层始终提高测试神经PDE代理的概括能力。
translated by 谷歌翻译
我们介绍了SubGD,这是一种新颖的几声学习方法,基于最近的发现,即随机梯度下降更新往往生活在低维参数子空间中。在实验和理论分析中,我们表明模型局限于合适的预定义子空间,可以很好地推广用于几次学习。合适的子空间符合给定任务的三个标准:IT(a)允许通过梯度流量减少训练误差,(b)导致模型良好的模型,并且(c)可以通过随机梯度下降来识别。 SUBGD从不同任务的更新说明的自动相关矩阵的特征组合中标识了这些子空间。明确的是,我们可以识别出低维合适的子空间,用于对动态系统的几次学习,而动态系统具有不同的属性,这些属性由分析系统描述的一个或几个参数描述。这种系统在科学和工程领域的现实应用程序中无处不在。我们在实验中证实了SubGD在三个不同的动态系统问题设置上的优势,在样本效率和性能方面,均超过了流行的几次学习方法。
translated by 谷歌翻译
包括协调性信息,例如位置,力,速度或旋转在计算物理和化学中的许多任务中是重要的。我们介绍了概括了等级图形网络的可控e(3)的等值图形神经网络(Segnns),使得节点和边缘属性不限于不变的标量,而是可以包含相协同信息,例如矢量或张量。该模型由可操纵的MLP组成,能够在消息和更新功能中包含几何和物理信息。通过可操纵节点属性的定义,MLP提供了一种新的Activation函数,以便与可转向功能字段一般使用。我们讨论我们的镜头通过等级的非线性卷曲镜头讨论我们的相关工作,进一步允许我们引脚点点的成功组件:非线性消息聚集在经典线性(可操纵)点卷积上改善;可操纵的消息在最近发送不变性消息的最近的等价图形网络上。我们展示了我们对计算物理学和化学的若干任务的方法的有效性,并提供了广泛的消融研究。
translated by 谷歌翻译
The abundance of data has given machine learning considerable momentum in natural sciences and engineering, though modeling of physical processes is often difficult. A particularly tough problem is the efficient representation of geometric boundaries. Triangularized geometric boundaries are well understood and ubiquitous in engineering applications. However, it is notoriously difficult to integrate them into machine learning approaches due to their heterogeneity with respect to size and orientation. In this work, we introduce an effective theory to model particle-boundary interactions, which leads to our new Boundary Graph Neural Networks (BGNNs) that dynamically modify graph structures to obey boundary conditions. The new BGNNs are tested on complex 3D granular flow processes of hoppers, rotating drums and mixers, which are all standard components of modern industrial machinery but still have complicated geometry. BGNNs are evaluated in terms of computational efficiency as well as prediction accuracy of particle flows and mixing entropies. BGNNs are able to accurately reproduce 3D granular flows within simulation uncertainties over hundreds of thousands of simulation timesteps. Most notably, in our experiments, particles stay within the geometric objects without using handcrafted conditions or restrictions.
translated by 谷歌翻译
强化学习算法在解决稀疏和延迟奖励的复杂分层任务时需要许多样本。对于此类复杂的任务,最近提出的方向舵使用奖励再分配来利用与完成子任务相关的Q功能中的步骤。但是,由于当前的探索策略无法在合理的时间内发现它们,因此通常只有很少有具有高回报的情节作为示范。在这项工作中,我们介绍了Align-rudder,该王牌利用了一个配置文件模型来进行奖励重新分布,该模型是从多个示范序列比对获得的。因此,Align-Rudder有效地采用了奖励再分配,从而大大改善了很少的演示学习。 Align-rudder在复杂的人工任务上的竞争者优于竞争对手,延迟的奖励和几乎没有示威的竞争者。在Minecraft获得Diamond的任务上,Align Rudder能够挖掘钻石,尽管不经常。代码可在https://github.com/ml-jku/align-rudder上找到。 YouTube:https://youtu.be/ho-_8zul-uy
translated by 谷歌翻译
Machine learning models are typically evaluated by computing similarity with reference annotations and trained by maximizing similarity with such. Especially in the bio-medical domain, annotations are subjective and suffer from low inter- and intra-rater reliability. Since annotations only reflect the annotation entity's interpretation of the real world, this can lead to sub-optimal predictions even though the model achieves high similarity scores. Here, the theoretical concept of Peak Ground Truth (PGT) is introduced. PGT marks the point beyond which an increase in similarity with the reference annotation stops translating to better Real World Model Performance (RWMP). Additionally, a quantitative technique to approximate PGT by computing inter- and intra-rater reliability is proposed. Finally, three categories of PGT-aware strategies to evaluate and improve model performance are reviewed.
translated by 谷歌翻译
Quaternion valued neural networks experienced rising popularity and interest from researchers in the last years, whereby the derivatives with respect to quaternions needed for optimization are calculated as the sum of the partial derivatives with respect to the real and imaginary parts. However, we can show that product- and chain-rule does not hold with this approach. We solve this by employing the GHRCalculus and derive quaternion backpropagation based on this. Furthermore, we experimentally prove the functionality of the derived quaternion backpropagation.
translated by 谷歌翻译
Neuromorphic systems require user-friendly software to support the design and optimization of experiments. In this work, we address this need by presenting our development of a machine learning-based modeling framework for the BrainScaleS-2 neuromorphic system. This work represents an improvement over previous efforts, which either focused on the matrix-multiplication mode of BrainScaleS-2 or lacked full automation. Our framework, called hxtorch.snn, enables the hardware-in-the-loop training of spiking neural networks within PyTorch, including support for auto differentiation in a fully-automated hardware experiment workflow. In addition, hxtorch.snn facilitates seamless transitions between emulating on hardware and simulating in software. We demonstrate the capabilities of hxtorch.snn on a classification task using the Yin-Yang dataset employing a gradient-based approach with surrogate gradients and densely sampled membrane observations from the BrainScaleS-2 hardware system.
translated by 谷歌翻译
Osteoarthritis (OA) is the most prevalent chronic joint disease worldwide, where knee OA takes more than 80% of commonly affected joints. Knee OA is not a curable disease yet, and it affects large columns of patients, making it costly to patients and healthcare systems. Etiology, diagnosis, and treatment of knee OA might be argued by variability in its clinical and physical manifestations. Although knee OA carries a list of well-known terminology aiming to standardize the nomenclature of the diagnosis, prognosis, treatment, and clinical outcomes of the chronic joint disease, in practice there is a wide range of terminology associated with knee OA across different data sources, including but not limited to biomedical literature, clinical notes, healthcare literacy, and health-related social media. Among these data sources, the scientific articles published in the biomedical literature usually make a principled pipeline to study disease. Rapid yet, accurate text mining on large-scale scientific literature may discover novel knowledge and terminology to better understand knee OA and to improve the quality of knee OA diagnosis, prevention, and treatment. The present works aim to utilize artificial neural network strategies to automatically extract vocabularies associated with knee OA diseases. Our finding indicates the feasibility of developing word embedding neural networks for autonomous keyword extraction and abstraction of knee OA.
translated by 谷歌翻译
Data-centric artificial intelligence (data-centric AI) represents an emerging paradigm emphasizing that the systematic design and engineering of data is essential for building effective and efficient AI-based systems. The objective of this article is to introduce practitioners and researchers from the field of Information Systems (IS) to data-centric AI. We define relevant terms, provide key characteristics to contrast the data-centric paradigm to the model-centric one, and introduce a framework for data-centric AI. We distinguish data-centric AI from related concepts and discuss its longer-term implications for the IS community.
translated by 谷歌翻译