物理知识的神经网络(PINN)在解决涉及部分微分方程的前进和反问题方面表现出了希望。尽管最近在扩展PINN可以解决的问题类别方面取得了进展,但大多数现有用例都涉及简单的几何域。迄今为止,还没有明确的方法来告知Pinns有关解决问题的域拓扑。在这项工作中,我们提出了一种基于拉普拉斯 - 贝特拉米操作员的特征函数的PINN的新型位置编码机制。该技术允许为代表给定对象几何形状的神经网络创建一个输入空间。我们近似具有有限元素的偏微分方程的特征函数以及涉及的操作员。我们对所提出的方法进行了广泛的测试和比较,以复杂形状(例如线圈,散热器和兔子),具有不同的物理学,例如二基核方程和传热。我们还研究了我们方法对所使用的本征函数数量的敏感性,以及用于本征函数和基础操作员的离散化。我们的结果表明,在传统的PINN无法产生有意义的解决方案的情况下,与地面真相数据非常吻合。我们设想这种新技术将扩大PINNS的有效性,以更现实的应用。
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我们提出了Fibernet,一种估计\ emph {in-Vivo}的方法,从电动激活的多个导管记录中,人心房的心脏纤维结构。心脏纤维在心脏的电力功能中起着核心作用,但是它们很难确定体内,因此在现有心脏模型中很少有特定于患者的特定于患者。 Fibernet通过解决物理知识的神经网络的逆问题来学习纤维布置。逆问题等于从一组稀疏激活图中识别心脏传播模型的传导速度张量。多个地图的使用可以同时识别传导速度张量(包括局部纤维角)的所有组件。我们对合成2-D和3-D示例,扩散张量纤维和患者特异性病例进行广泛测试。我们表明,在存在噪声的情况下,也足以准确捕获纤维。随着地图的较少,正则化的作用变得突出。此外,我们表明拟合的模型可以稳健地重现看不见的激活图。我们设想,纤维网将帮助创建特定于患者的个性化医学模型。完整代码可在http://github.com/fsahli/fibernet上找到。
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心脏电生理学领域试图摘要,描述并最终模拟心跳的电气特性。随着近期心脏电生理学的进展,模型与以往更强大和描述。然而,为了前进到逆电生理学建模领域,即从诸如ECG的电测量中创建模型,较少调查的模拟ECGS的平滑度W.R.T.需要进一步探索模型参数。本文在整个管道方面讨论了描述了描述生理参数的方式,我们到达模拟的心电图。采用这种管道,我们创建了一种简化理想化的左心室模型的测试台,并通过平滑成本函数来证明高效逆建模的最重要因素。这些知识对于在未来的优化和机器学习方法中设计和创建逆模型非常重要。
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心房颤动的计算模型已成功地用于预测最佳消融部位。评估消融模式的效果的关键步骤是从不同,潜在的随机的位置加速模型以确定是否可以在ATRIA中诱导心律失常。在这项工作中,我们建议使用黎曼歧管的多保真高斯过程分类,以有效地确定心律失常是诱导性诱导的区域内的区域。我们构建一个直接在心房表面上运行的概率分类器。我们利用较低的分辨率模型来探索心房表面,并与高分辨率模型无缝结合,以识别诱导区域。当用40个样本培训时,我们的多保真性分级器显示了比使用作为基线心房颤动模型的最近邻分类器的均衡精度,并且在心房颤动的情况下具有9%。我们希望这种新技术将允许更快,更精确地对心房颤动的计算模型临床应用。
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Linguists distinguish between novel and conventional metaphor, a distinction which the metaphor detection task in NLP does not take into account. Instead, metaphoricity is formulated as a property of a token in a sentence, regardless of metaphor type. In this paper, we investigate the limitations of treating conventional metaphors in this way, and advocate for an alternative which we name 'metaphorical polysemy detection' (MPD). In MPD, only conventional metaphoricity is treated, and it is formulated as a property of word senses in a lexicon. We develop the first MPD model, which learns to identify conventional metaphors in the English WordNet. To train it, we present a novel training procedure that combines metaphor detection with word sense disambiguation (WSD). For evaluation, we manually annotate metaphor in two subsets of WordNet. Our model significantly outperforms a strong baseline based on a state-of-the-art metaphor detection model, attaining an ROC-AUC score of .78 (compared to .65) on one of the sets. Additionally, when paired with a WSD model, our approach outperforms a state-of-the-art metaphor detection model at identifying conventional metaphors in text (.659 F1 compared to .626).
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A widely acknowledged shortcoming of WordNet is that it lacks a distinction between word meanings which are systematically related (polysemy), and those which are coincidental (homonymy). Several previous works have attempted to fill this gap, by inferring this information using computational methods. We revisit this task, and exploit recent advances in language modelling to synthesise homonymy annotation for Princeton WordNet. Previous approaches treat the problem using clustering methods; by contrast, our method works by linking WordNet to the Oxford English Dictionary, which contains the information we need. To perform this alignment, we pair definitions based on their proximity in an embedding space produced by a Transformer model. Despite the simplicity of this approach, our best model attains an F1 of .97 on an evaluation set that we annotate. The outcome of our work is a high-quality homonymy annotation layer for Princeton WordNet, which we release.
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Binarized Neural Networks (BNNs) are receiving increasing attention due to their lightweight architecture and ability to run on low-power devices. The state-of-the-art for training classification BNNs restricted to few-shot learning is based on a Mixed Integer Programming (MIP) approach. This paper proposes the BeMi ensemble, a structured architecture of BNNs based on training a single BNN for each possible pair of classes and applying a majority voting scheme to predict the final output. The training of a single BNN discriminating between two classes is achieved by a MIP model that optimizes a lexicographic multi-objective function according to robustness and simplicity principles. This approach results in training networks whose output is not affected by small perturbations on the input and whose number of active weights is as small as possible, while good accuracy is preserved. We computationally validate our model using the MNIST and Fashion-MNIST datasets using up to 40 training images per class. Our structured ensemble outperforms both BNNs trained by stochastic gradient descent and state-of-the-art MIP-based approaches. While the previous approaches achieve an average accuracy of 51.1% on the MNIST dataset, the BeMi ensemble achieves an average accuracy of 61.7% when trained with 10 images per class and 76.4% when trained with 40 images per class.
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One of the common traits of past and present approaches for Semantic Role Labeling (SRL) is that they rely upon discrete labels drawn from a predefined linguistic inventory to classify predicate senses and their arguments. However, we argue this need not be the case. In this paper, we present an approach that leverages Definition Modeling to introduce a generalized formulation of SRL as the task of describing predicate-argument structures using natural language definitions instead of discrete labels. Our novel formulation takes a first step towards placing interpretability and flexibility foremost, and yet our experiments and analyses on PropBank-style and FrameNet-style, dependency-based and span-based SRL also demonstrate that a flexible model with an interpretable output does not necessarily come at the expense of performance. We release our software for research purposes at https://github.com/SapienzaNLP/dsrl.
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In this new computing paradigm, named quantum computing, researchers from all over the world are taking their first steps in designing quantum circuits for image processing, through a difficult process of knowledge transfer. This effort is named Quantum Image Processing, an emerging research field pushed by powerful parallel computing capabilities of quantum computers. This work goes in this direction and proposes the challenging development of a powerful method of image denoising, such as the Total Variation (TV) model, in a quantum environment. The proposed Quantum TV is described and its sub-components are analysed. Despite the natural limitations of the current capabilities of quantum devices, the experimental results show a competitive denoising performance compared to the classical variational TV counterpart.
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In this paper, we introduced the novel concept of advisor network to address the problem of noisy labels in image classification. Deep neural networks (DNN) are prone to performance reduction and overfitting problems on training data with noisy annotations. Weighting loss methods aim to mitigate the influence of noisy labels during the training, completely removing their contribution. This discarding process prevents DNNs from learning wrong associations between images and their correct labels but reduces the amount of data used, especially when most of the samples have noisy labels. Differently, our method weighs the feature extracted directly from the classifier without altering the loss value of each data. The advisor helps to focus only on some part of the information present in mislabeled examples, allowing the classifier to leverage that data as well. We trained it with a meta-learning strategy so that it can adapt throughout the training of the main model. We tested our method on CIFAR10 and CIFAR100 with synthetic noise, and on Clothing1M which contains real-world noise, reporting state-of-the-art results.
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