卷积神经网络(CNN)在各种应用中表现出卓越的性能,但具有较高的计算复杂性。量化用于降低CNN的延迟和存储成本。在量化方法中,二进制重量网络(BWN和TWNS)在8位和4位量化方面具有独特的优势。他们用加法替代CNN中的乘法操作,这些操作在内存计数(IMC)设备上受到青睐。 BWNS的IMC加速度已被广泛研究。但是,尽管TWN的精度比BWN具有更高的准确性和更好的稀疏性,但IMC的加速度的研究有限。现有的IMC设备上的TWN效率低下,因为稀疏性无法很好地利用,并且加法操作效率不高。在本文中,我们建议FAT作为TWN的新型IMC加速器。首先,我们提出了一个稀疏的加法控制单元,该单元利用TWN的稀疏度跳过了零重量的无效操作。其次,我们提出了一个基于内存感知器的快速添加方案,以避免携带传播的时间开销并将其写回记忆单元。第三,我们进一步提出了一个组合的数据映射,以减少激活和权重的数据移动,并增加跨内存列的并行性。仿真结果表明,与最先进的IMC加速器Parapim相比,对于感官放大器水平上的加法操作,FAT达到2.00倍加速度,1.22倍功率效率和1.22倍面积效率。与帕拉皮姆(Parapim)相比,脂肪达到10.02倍的加速度和12.19倍的能量效率,而平均稀疏性为80%的网络。
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A key feature of federated learning (FL) is to preserve the data privacy of end users. However, there still exist potential privacy leakage in exchanging gradients under FL. As a result, recent research often explores the differential privacy (DP) approaches to add noises to the computing results to address privacy concerns with low overheads, which however degrade the model performance. In this paper, we strike the balance of data privacy and efficiency by utilizing the pervasive social connections between users. Specifically, we propose SCFL, a novel Social-aware Clustered Federated Learning scheme, where mutually trusted individuals can freely form a social cluster and aggregate their raw model updates (e.g., gradients) inside each cluster before uploading to the cloud for global aggregation. By mixing model updates in a social group, adversaries can only eavesdrop the social-layer combined results, but not the privacy of individuals. We unfold the design of SCFL in three steps. \emph{i) Stable social cluster formation. Considering users' heterogeneous training samples and data distributions, we formulate the optimal social cluster formation problem as a federation game and devise a fair revenue allocation mechanism to resist free-riders. ii) Differentiated trust-privacy mapping}. For the clusters with low mutual trust, we design a customizable privacy preservation mechanism to adaptively sanitize participants' model updates depending on social trust degrees. iii) Distributed convergence}. A distributed two-sided matching algorithm is devised to attain an optimized disjoint partition with Nash-stable convergence. Experiments on Facebook network and MNIST/CIFAR-10 datasets validate that our SCFL can effectively enhance learning utility, improve user payoff, and enforce customizable privacy protection.
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Objective: Imbalances of the electrolyte concentration levels in the body can lead to catastrophic consequences, but accurate and accessible measurements could improve patient outcomes. While blood tests provide accurate measurements, they are invasive and the laboratory analysis can be slow or inaccessible. In contrast, an electrocardiogram (ECG) is a widely adopted tool which is quick and simple to acquire. However, the problem of estimating continuous electrolyte concentrations directly from ECGs is not well-studied. We therefore investigate if regression methods can be used for accurate ECG-based prediction of electrolyte concentrations. Methods: We explore the use of deep neural networks (DNNs) for this task. We analyze the regression performance across four electrolytes, utilizing a novel dataset containing over 290000 ECGs. For improved understanding, we also study the full spectrum from continuous predictions to binary classification of extreme concentration levels. To enhance clinical usefulness, we finally extend to a probabilistic regression approach and evaluate different uncertainty estimates. Results: We find that the performance varies significantly between different electrolytes, which is clinically justified in the interplay of electrolytes and their manifestation in the ECG. We also compare the regression accuracy with that of traditional machine learning models, demonstrating superior performance of DNNs. Conclusion: Discretization can lead to good classification performance, but does not help solve the original problem of predicting continuous concentration levels. While probabilistic regression demonstrates potential practical usefulness, the uncertainty estimates are not particularly well-calibrated. Significance: Our study is a first step towards accurate and reliable ECG-based prediction of electrolyte concentration levels.
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Skull Stripping is a requisite preliminary step in most diagnostic neuroimaging applications. Manual Skull Stripping methods define the gold standard for the domain but are time-consuming and challenging to integrate into pro-cessing pipelines with a high number of data samples. Automated methods are an active area of research for head MRI segmentation, especially deep learning methods such as U-Net architecture implementations. This study compares Vanilla, Residual, and Dense 2D U-Net architectures for Skull Stripping. The Dense 2D U-Net architecture outperforms the Vanilla and Residual counterparts by achieving an accuracy of 99.75% on a test dataset. It is observed that dense interconnections in a U-Net encourage feature reuse across layers of the architecture and allow for shallower models with the strengths of a deeper network.
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Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.
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Predictive simulations of the shock-to-detonation transition (SDT) in heterogeneous energetic materials (EM) are vital to the design and control of their energy release and sensitivity. Due to the complexity of the thermo-mechanics of EM during the SDT, both macro-scale response and sub-grid mesoscale energy localization must be captured accurately. This work proposes an efficient and accurate multiscale framework for SDT simulations of EM. We employ deep learning to model the mesoscale energy localization of shock-initiated EM microstructures upon which prediction results are used to supply reaction progress rate information to the macroscale SDT simulation. The proposed multiscale modeling framework is divided into two stages. First, a physics-aware recurrent convolutional neural network (PARC) is used to model the mesoscale energy localization of shock-initiated heterogeneous EM microstructures. PARC is trained using direct numerical simulations (DNS) of hotspot ignition and growth within microstructures of pressed HMX material subjected to different input shock strengths. After training, PARC is employed to supply hotspot ignition and growth rates for macroscale SDT simulations. We show that PARC can play the role of a surrogate model in a multiscale simulation framework, while drastically reducing the computation cost and providing improved representations of the sub-grid physics. The proposed multiscale modeling approach will provide a new tool for material scientists in designing high-performance and safer energetic materials.
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在图像分类中,在检测分布(OOD)数据时发生了许多发展。但是,大多数OOD检测方法是在一组标准数据集上评估的,该数据集与培训数据任意不同。没有明确的定义``好的''ood数据集。此外,最先进的OOD检测方法已经在这些标准基准上取得了几乎完美的结果。在本文中,我们定义了2类OOD数据使用与分布(ID)数据的感知/视觉和语义相似性的微妙概念。我们将附近的OOD样本定义为感知上相似但语义上与ID样本的不同,并将样本转移为视觉上不同但在语义上与ID相似的点数据。然后,我们提出了一个基于GAN的框架,用于从这两个类别中生成OOD样品,给定一个ID数据集。通过有关MNIST,CIFAR-10/100和Imagenet的广泛实验,我们表明A)在常规基准上表现出色的ART OOD检测方法对我们提出的基准测试的稳健性明显较小。 N基准测试,反之亦然,因此表明甚至可能不需要单独的OOD集来可靠地评估OOD检测中的性能。
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在评估临床机器学习模型的性能时,必须考虑部署人群。当观察到的标签患者的人群只是部署人群的一部分(选择标签)时,对观察到的人群的标准模型绩效估计可能会产生误导。在这项研究中,我们描述了三类的标签选择,并模拟了五个有因果关系的场景,以评估特定选择机制如何偏向一套常见的二进制机器学习模型性能指标。 Simulations reveal that when selection is affected by observed features, naive estimates of model discrimination may be misleading. When selection is affected by labels, naive estimates of calibration fail to reflect reality.我们从因果推理文献中借用传统的加权估计器,发现当正确指定选择概率时,它们会恢复全部人口估计。然后,我们解决了监视部署的机器学习模型的性能的现实任务,该模型的相互作用与临床医生相互作用并影响标签的选择机制。我们训练三个机器学习模型来标记低收益实验室的诊断,并模拟它们减少浪费实验室利用的预期结果。我们发现,对观察到的人群的幼稚估计值降低了20%。这样的差异可能足够大,可以导致成功终止成功的临床决策支持工具。我们提出了一个更改的部署程序,该程序将注入随机化的注入随机化与传统加权估计相结合,并发现其恢复了真正的模型性能。
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现有的数据驱动和反馈流量控制策略不考虑实时数据测量的异质性。此外,对于缺乏数据效率,传统的加固学习方法(RL)方法通常会缓慢收敛。此外,常规的最佳外围控制方案需要对系统动力学的精确了解,因此对内源性不确定性会很脆弱。为了应对这些挑战,这项工作提出了一种基于不可或缺的增强学习(IRL)的方法来学习宏观交通动态,以进行自适应最佳周边控制。这项工作为运输文献做出了以下主要贡献:(a)开发连续的时间控制,并具有离散增益更新以适应离散时间传感器数据。 (b)为了降低采样复杂性并更有效地使用可用数据,将体验重播(ER)技术引入IRL算法。 (c)所提出的方法以“无模型”方式放松模型校准的要求,该方式可以稳健地进行建模不确定性,并通过数据驱动的RL算法增强实时性能。 (d)通过Lyapunov理论证明了基于IRL的算法和受控交通动力学的稳定性的收敛性。最佳控制定律被参数化,然后通过神经网络(NN)近似,从而缓解计算复杂性。在不需要模型线性化的同时,考虑了状态和输入约束。提出了数值示例和仿真实验,以验证所提出方法的有效性和效率。
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ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列,该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战,这是由于探测器的几何形状,不均匀的散射和冰中光的吸收,并且低于100 GEV的光,每个事件产生的信号光子数量相对较少。为了应对这一挑战,可以将ICECUBE事件表示为点云图形,并将图形神经网络(GNN)作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开,对不同的中微子事件类型进行分类,并重建沉积的能量,方向和相互作用顶点。基于仿真,我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术,包括已知系统不确定性的影响。对于中微子事件分类,与当前的IceCube方法相比,GNN以固定的假阳性速率(FPR)提高了信号效率的18%。另外,GNN在固定信号效率下将FPR的降低超过8(低于半百分比)。对于能源,方向和相互作用顶点的重建,与当前最大似然技术相比,分辨率平均提高了13%-20%。当在GPU上运行时,GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件,这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。
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