交叉设备联合学习(FL)是一种分布式学习范例,具有几种挑战,这些挑战将其区分离为传统的分布式学习,每个设备上的系统特征的可变性,以及数百万客户端与主要服务器协调。文献中描述的大多数FL系统是同步的 - 它们从各个客户端执行模型更新的同步聚合。缩放同步FL是挑战,因为增加了并行培训的客户数量导致训练速度的回报递减,类似于大批培训。而且,陷阱妨碍了同步流动训练。在这项工作中,我们概述了一种生产异步流行系统设计。我们的工作解决了上述问题,一些系统设计挑战及其解决方案的草图,并触及了为数百万客户建立生产流系统的原则。凭经验,我们证明异步流量在跨越近一亿台设备时比同步液更快地收敛。特别地,在高并发设置中,异步FL速度快5倍,并且具有比同步FL更小的通信开销差距。
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强化学习(RL)的概括对于RL算法的实际部署至关重要。提出了各种方案来解决概括问题,包括转移学习,多任务学习和元学习,以及健壮和对抗性的强化学习。但是,各种方案都没有统一的表述,也没有跨不同方案的方法的全面比较。在这项工作中,我们提出了一个游戏理论框架,用于加强学习的概括,名为Girl,在该框架中,RL代理在一组任务中对对手进行了训练,对手可以在给定阈值内对任务进行分配。使用不同的配置,女孩可以减少上述各种方案。为了解决女孩,我们将广泛使用的方法改编在游戏理论中,策略空间响应Oracle(PSRO)进行以下三个重要修改:i)我们使用模型 - 静脉元学习(MAML)作为最佳反应甲骨文,II)我们提出了一个经过修改的投影复制的动力学,即R-PRD,该动力学确保了对手的计算元策略在阈值中,并且iii)我们还为测试过程中的多个策略进行了几次学习的协议。关于穆约科科环境的广泛实验表明,我们提出的方法可以胜过现有的基线,例如MAML。
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从任意堕落状态中起床是一种基本的人类技能。现有的学习这种技能的方法通常会产生高度动态和不稳定的起床动作,这不像人类的起床策略,或者基于跟踪记录的人类起床运动。在本文中,我们提出了一种使用强化学习的分阶段方法,而无需求助于运动捕获数据。该方法首先利用了强大的字符模型,从而有助于发现解决方案模式。然后,第二阶段学会了调整控制策略,以逐步与角色的较弱版本一起使用。最后,第三阶段学习控制政策,这些政策可以以较慢的速度重现较弱的起床动作。我们表明,在多个运行中,该方法可以发现各种各样的起床策略,并以各种速度执行它们。结果通常会产生采用最终站立策略的策略,这些策略是从所有初始状态中看到的恢复动作所共有的。但是,我们还发现了对俯卧和仰卧初始堕落状态的不同策略的政策。学识渊博的起床控制策略通常具有明显的静态稳定性,即,在起床运动过程中,它们可以在各个点停下来。我们进一步测试了新的限制场景的方法,例如在演员表中有一条腿和手臂。
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神经网络(NNS)在广泛的应用中的成功导致对理解这些模型的潜在学习动态的兴趣增加。在本文中,我们通过采用图形透视并调查NNS图形结构与其性能之间的关系来超越学习动态的描述。具体地,我们提出(1)表示神经网络学习过程作为时间不断发展的图表(即,通过时代的一系列静态图形快照),(2)在简单的时间内捕获NN期间NN的结构变化发明内容,(3)利用结构摘要,以预测底层NN在分类或回归任务中的准确性。对于NNS的动态图形表示,我们探索完全连接和卷积层的结构表示,这是强大的NN模型的关键组件。我们的分析表明,图形统计数据简单摘要,如加权程度和特征向量中心,只能用于准确地预测NNS的性能。例如,基于Lenet架构的5次训练时期构造的基于加权的基于程度的概要,实现了超过93%的分类精度。我们的发现对于不同的NN架构,包括Lenet,VGG,AlexNet和Reset。
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Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.
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To generate high quality rendering images for real time applications, it is often to trace only a few samples-per-pixel (spp) at a lower resolution and then supersample to the high resolution. Based on the observation that the rendered pixels at a low resolution are typically highly aliased, we present a novel method for neural supersampling based on ray tracing 1/4-spp samples at the high resolution. Our key insight is that the ray-traced samples at the target resolution are accurate and reliable, which makes the supersampling an interpolation problem. We present a mask-reinforced neural network to reconstruct and interpolate high-quality image sequences. First, a novel temporal accumulation network is introduced to compute the correlation between current and previous features to significantly improve their temporal stability. Then a reconstruct network based on a multi-scale U-Net with skip connections is adopted for reconstruction and generation of the desired high-resolution image. Experimental results and comparisons have shown that our proposed method can generate higher quality results of supersampling, without increasing the total number of ray-tracing samples, over current state-of-the-art methods.
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Temporal sentence grounding (TSG) aims to identify the temporal boundary of a specific segment from an untrimmed video by a sentence query. All existing works first utilize a sparse sampling strategy to extract a fixed number of video frames and then conduct multi-modal interactions with query sentence for reasoning. However, we argue that these methods have overlooked two indispensable issues: 1) Boundary-bias: The annotated target segment generally refers to two specific frames as corresponding start and end timestamps. The video downsampling process may lose these two frames and take the adjacent irrelevant frames as new boundaries. 2) Reasoning-bias: Such incorrect new boundary frames also lead to the reasoning bias during frame-query interaction, reducing the generalization ability of model. To alleviate above limitations, in this paper, we propose a novel Siamese Sampling and Reasoning Network (SSRN) for TSG, which introduces a siamese sampling mechanism to generate additional contextual frames to enrich and refine the new boundaries. Specifically, a reasoning strategy is developed to learn the inter-relationship among these frames and generate soft labels on boundaries for more accurate frame-query reasoning. Such mechanism is also able to supplement the absent consecutive visual semantics to the sampled sparse frames for fine-grained activity understanding. Extensive experiments demonstrate the effectiveness of SSRN on three challenging datasets.
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Representing and synthesizing novel views in real-world dynamic scenes from casual monocular videos is a long-standing problem. Existing solutions typically approach dynamic scenes by applying geometry techniques or utilizing temporal information between several adjacent frames without considering the underlying background distribution in the entire scene or the transmittance over the ray dimension, limiting their performance on static and occlusion areas. Our approach $\textbf{D}$istribution-$\textbf{D}$riven neural radiance fields offers high-quality view synthesis and a 3D solution to $\textbf{D}$etach the background from the entire $\textbf{D}$ynamic scene, which is called $\text{D}^4$NeRF. Specifically, it employs a neural representation to capture the scene distribution in the static background and a 6D-input NeRF to represent dynamic objects, respectively. Each ray sample is given an additional occlusion weight to indicate the transmittance lying in the static and dynamic components. We evaluate $\text{D}^4$NeRF on public dynamic scenes and our urban driving scenes acquired from an autonomous-driving dataset. Extensive experiments demonstrate that our approach outperforms previous methods in rendering texture details and motion areas while also producing a clean static background. Our code will be released at https://github.com/Luciferbobo/D4NeRF.
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Deploying reliable deep learning techniques in interdisciplinary applications needs learned models to output accurate and ({even more importantly}) explainable predictions. Existing approaches typically explicate network outputs in a post-hoc fashion, under an implicit assumption that faithful explanations come from accurate predictions/classifications. We have an opposite claim that explanations boost (or even determine) classification. That is, end-to-end learning of explanation factors to augment discriminative representation extraction could be a more intuitive strategy to inversely assure fine-grained explainability, e.g., in those neuroimaging and neuroscience studies with high-dimensional data containing noisy, redundant, and task-irrelevant information. In this paper, we propose such an explainable geometric deep network dubbed as NeuroExplainer, with applications to uncover altered infant cortical development patterns associated with preterm birth. Given fundamental cortical attributes as network input, our NeuroExplainer adopts a hierarchical attention-decoding framework to learn fine-grained attentions and respective discriminative representations to accurately recognize preterm infants from term-born infants at term-equivalent age. NeuroExplainer learns the hierarchical attention-decoding modules under subject-level weak supervision coupled with targeted regularizers deduced from domain knowledge regarding brain development. These prior-guided constraints implicitly maximizes the explainability metrics (i.e., fidelity, sparsity, and stability) in network training, driving the learned network to output detailed explanations and accurate classifications. Experimental results on the public dHCP benchmark suggest that NeuroExplainer led to quantitatively reliable explanation results that are qualitatively consistent with representative neuroimaging studies.
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Domain adaptation methods reduce domain shift typically by learning domain-invariant features. Most existing methods are built on distribution matching, e.g., adversarial domain adaptation, which tends to corrupt feature discriminability. In this paper, we propose Discriminative Radial Domain Adaptation (DRDR) which bridges source and target domains via a shared radial structure. It's motivated by the observation that as the model is trained to be progressively discriminative, features of different categories expand outwards in different directions, forming a radial structure. We show that transferring such an inherently discriminative structure would enable to enhance feature transferability and discriminability simultaneously. Specifically, we represent each domain with a global anchor and each category a local anchor to form a radial structure and reduce domain shift via structure matching. It consists of two parts, namely isometric transformation to align the structure globally and local refinement to match each category. To enhance the discriminability of the structure, we further encourage samples to cluster close to the corresponding local anchors based on optimal-transport assignment. Extensively experimenting on multiple benchmarks, our method is shown to consistently outperforms state-of-the-art approaches on varied tasks, including the typical unsupervised domain adaptation, multi-source domain adaptation, domain-agnostic learning, and domain generalization.
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