Recent advances in deep learning have enabled us to address the curse of dimensionality (COD) by solving problems in higher dimensions. A subset of such approaches of addressing the COD has led us to solving high-dimensional PDEs. This has resulted in opening doors to solving a variety of real-world problems ranging from mathematical finance to stochastic control for industrial applications. Although feasible, these deep learning methods are still constrained by training time and memory. Tackling these shortcomings, Tensor Neural Networks (TNN) demonstrate that they can provide significant parameter savings while attaining the same accuracy as compared to the classical Dense Neural Network (DNN). In addition, we also show how TNN can be trained faster than DNN for the same accuracy. Besides TNN, we also introduce Tensor Network Initializer (TNN Init), a weight initialization scheme that leads to faster convergence with smaller variance for an equivalent parameter count as compared to a DNN. We benchmark TNN and TNN Init by applying them to solve the parabolic PDE associated with the Heston model, which is widely used in financial pricing theory.
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Deep neural networks have long training and processing times. Early exits added to neural networks allow the network to make early predictions using intermediate activations in the network in time-sensitive applications. However, early exits increase the training time of the neural networks. We introduce QuickNets: a novel cascaded training algorithm for faster training of neural networks. QuickNets are trained in a layer-wise manner such that each successive layer is only trained on samples that could not be correctly classified by the previous layers. We demonstrate that QuickNets can dynamically distribute learning and have a reduced training cost and inference cost compared to standard Backpropagation. Additionally, we introduce commitment layers that significantly improve the early exits by identifying for over-confident predictions and demonstrate its success.
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Recent work has reported that AI classifiers trained on audio recordings can accurately predict severe acute respiratory syndrome coronavirus 2 (SARSCoV2) infection status. Here, we undertake a large scale study of audio-based deep learning classifiers, as part of the UK governments pandemic response. We collect and analyse a dataset of audio recordings from 67,842 individuals with linked metadata, including reverse transcription polymerase chain reaction (PCR) test outcomes, of whom 23,514 tested positive for SARS CoV 2. Subjects were recruited via the UK governments National Health Service Test-and-Trace programme and the REal-time Assessment of Community Transmission (REACT) randomised surveillance survey. In an unadjusted analysis of our dataset AI classifiers predict SARS-CoV-2 infection status with high accuracy (Receiver Operating Characteristic Area Under the Curve (ROCAUC) 0.846 [0.838, 0.854]) consistent with the findings of previous studies. However, after matching on measured confounders, such as age, gender, and self reported symptoms, our classifiers performance is much weaker (ROC-AUC 0.619 [0.594, 0.644]). Upon quantifying the utility of audio based classifiers in practical settings, we find them to be outperformed by simple predictive scores based on user reported symptoms.
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Fast timescale state estimation for a large power system can be challenging if the sensors producing the measurements are few in number. This is particularly true for doing time-synchronized state estimation for a transmission system that has minimal phasor measurement unit (PMU) coverage. This paper proposes a Deep Neural network-based State Estimator (DeNSE) to overcome this extreme unobservability problem. For systems in which the existing PMU infrastructure is not able to bring the estimation errors within acceptable limits using the DeNSE, a data-driven incremental PMU placement methodology is also introduced. The practical utility of the proposed approach is demonstrated by considering topology changes, non-Gaussian measurement noise, bad data detection and correction, and large system application.
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Automated identification of myocardial scar from late gadolinium enhancement cardiac magnetic resonance images (LGE-CMR) is limited by image noise and artifacts such as those related to motion and partial volume effect. This paper presents a novel joint deep learning (JDL) framework that improves such tasks by utilizing simultaneously learned myocardium segmentations to eliminate negative effects from non-region-of-interest areas. In contrast to previous approaches treating scar detection and myocardium segmentation as separate or parallel tasks, our proposed method introduces a message passing module where the information of myocardium segmentation is directly passed to guide scar detectors. This newly designed network will efficiently exploit joint information from the two related tasks and use all available sources of myocardium segmentation to benefit scar identification. We demonstrate the effectiveness of JDL on LGE-CMR images for automated left ventricular (LV) scar detection, with great potential to improve risk prediction in patients with both ischemic and non-ischemic heart disease and to improve response rates to cardiac resynchronization therapy (CRT) for heart failure patients. Experimental results show that our proposed approach outperforms multiple state-of-the-art methods, including commonly used two-step segmentation-classification networks, and multitask learning schemes where subtasks are indirectly interacted.
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The selection of an optimal pacing site, which is ideally scar-free and late activated, is critical to the response of cardiac resynchronization therapy (CRT). Despite the success of current approaches formulating the detection of such late mechanical activation (LMA) regions as a problem of activation time regression, their accuracy remains unsatisfactory, particularly in cases where myocardial scar exists. To address this issue, this paper introduces a multi-task deep learning framework that simultaneously estimates LMA amount and classify the scar-free LMA regions based on cine displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI). With a newly introduced auxiliary LMA region classification sub-network, our proposed model shows more robustness to the complex pattern cause by myocardial scar, significantly eliminates their negative effects in LMA detection, and in turn improves the performance of scar classification. To evaluate the effectiveness of our method, we tests our model on real cardiac MR images and compare the predicted LMA with the state-of-the-art approaches. It shows that our approach achieves substantially increased accuracy. In addition, we employ the gradient-weighted class activation mapping (Grad-CAM) to visualize the feature maps learned by all methods. Experimental results suggest that our proposed model better recognizes the LMA region pattern.
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运营商网络已成为有希望的深度学习工具,用于近似偏微分方程(PDE)的解决方案。这些网络绘制了描述材料属性,迫使函数和边界数据的输入函数到PDE解决方案。这项工作描述了一种针对操作员网络的新体系结构,该架构模仿了从问题的变异公式或弱公式中获得的数值解决方案的形式。这些想法在通用椭圆的PDE中的应用导致变异模拟操作员网络(Varmion)。像常规的深层操作员网络(DeepOnet)一样,Varmion也由一个子网络组成,该子网络构建了输出的基础函数,另一个构造了这些基础函数系数的基本功能。但是,与deponet相反,在Varmion中,这些网络的体系结构是精确确定的。对Varmion解决方案中误差的分析表明,它包含训练数据中的误差,训练错误,抽样输入中的正交误差和输出功能的贡献,以及测量测试输入功能之间距离的“覆盖错误”以及培训数据集中最近的功能。这也取决于确切网络及其varmion近似的稳定性常数。 Varmion在规范椭圆形PDE中的应用表明,对于大约相同数量的网络参数,平均而言,Varmion的误差比标准DeepOnet较小。此外,其性能对于输入函数的变化,用于采样输入和输出功能的技术,用于构建基本函数的技术以及输入函数的数量更为强大。
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近年来,基于神经网络的深度恢复方法已实现了最先进的方法,从而导致了各种图像过度的任务。但是,基于深度学习的Deblurring网络的一个主要缺点是,训练需要大量模糊清洁图像对才能实现良好的性能。此外,当测试过程中的模糊图像和模糊内核与训练过程中使用的图像和模糊内核时,深层网络通常无法表现良好。这主要是因为网络参数在培训数据上过度拟合。在这项工作中,我们提出了一种解决这些问题的方法。我们将非盲图像脱毛问题视为一个脱氧问题。为此,我们在一对模糊图像上使用相应的模糊内核进行Wiener过滤。这导致一对具有彩色噪声的图像。因此,造成造成的问题被转化为一个降解问题。然后,我们在不使用明确的清洁目标图像的情况下解决了降解问题。进行了广泛的实验,以表明我们的方法取得了与最先进的非盲人脱毛作品相提并论的结果。
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现代监视系统使用基于深度学习的面部验证网络执行人员认可。大多数最先进的面部验证系统都是使用可见光谱图像训练的。但是,在弱光和夜间条件的情况下,在可见光谱中获取图像是不切实际的,并且通常在诸如热红外域之类的替代域中捕获图像。在检索相应的可见域图像后,通常在热图像中进行面部验证。这是一个公认的问题,通常称为热能(T2V)图像翻译。在本文中,我们建议针对面部图像的T2V翻译基于Denoising扩散概率模型(DDPM)解决方案。在训练过程中,该模型通过扩散过程了解了它们相应的热图像,可见面部图像的条件分布。在推断过程中,可见的域图像是通过从高斯噪声开始并反复执行的。 DDPM的现有推理过程是随机且耗时的。因此,我们提出了一种新颖的推理策略,以加快DDPM的推理时间,特别是用于T2V图像翻译问题。我们在多个数据集上实现了最新结果。代码和验证的模型可在http://github.com/nithin-gk/t2v-ddpm上公开获得
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这项研究提出了一种基于深度学习的超声(US)图像引导放射疗法的跟踪方法。拟议的级联深度学习模型由注意力网络,基于掩模区域的卷积神经网络(Mask R-CNN)和长期短期记忆(LSTM)网络组成。注意网络从美国图像到可疑的具有里程碑意义的运动区域,以减少搜索区域。然后,面膜R-CNN在减少区域中产生多个利益区域(ROI)建议,并通过三个网络头确定拟议的地标:边界框回归,提案分类和地标分段。 LSTM网络对连续的图像框架之间的时间关系建模,以进行边界框回归和建议分类。为了合并最终建议,根据顺序框架之间的相似性设计选择方法。该方法在肝脏美国跟踪数据集中测试了医疗图像计算和计算机辅助干预措施(MICCAI)2015年的挑战,其中有三位经验丰富的观察者注释了地标,以获得其平均位置。在24个鉴于我们具有地面真相的序列的24个序列上,所有地标的平均跟踪误差为0.65 +/- 0.56毫米,所有地标的误差均在2 mm之内。我们进一步测试了从测试数据集中的69个地标上提出的模型,该模型具有与训练模式相似的图像模式,从而导致平均跟踪误差为0.94 +/- 0.83 mm。我们的实验结果表明,我们提出的方法使用US图像跟踪肝解剖学地标的可行性和准确性,为放射治疗期间的主动运动管理提供了潜在的解决方案。
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