The statistical heterogeneity of the non-independent and identically distributed (non-IID) data in local clients significantly limits the performance of federated learning. Previous attempts like FedProx, SCAFFOLD, MOON, FedNova and FedDyn resort to an optimization perspective, which requires an auxiliary term or re-weights local updates to calibrate the learning bias or the objective inconsistency. However, in addition to previous explorations for improvement in federated averaging, our analysis shows that another critical bottleneck is the poorer optima of client models in more heterogeneous conditions. We thus introduce a data-driven approach called FedSkip to improve the client optima by periodically skipping federated averaging and scattering local models to the cross devices. We provide theoretical analysis of the possible benefit from FedSkip and conduct extensive experiments on a range of datasets to demonstrate that FedSkip achieves much higher accuracy, better aggregation efficiency and competing communication efficiency. Source code is available at: https://github.com/MediaBrain-SJTU/FedSkip.
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机上的机器学习使本地客户端推荐模型的轻量级部署可以减轻基于云的推荐人的负担,并同时结合了更多实时用户功能。然而,考虑到其强大的模型能力以及从十亿级项目库中产生的有效候选人,该行业的基于云的建议仍然非常重要。以前的尝试将两种范式的优点整合起来主要诉诸于顺序机制,该机制在基于云的建议之上构建了在设备上的推荐人。但是,当用户兴趣发生巨大变化时,这种设计是不灵活的:设备模型被有限的项目缓存粘住,而基于大型项目池的基于云的推荐则没有新的重新汇总反馈。为了克服这个问题,我们提出了一个元控制器,以动态管理推荐装置推荐人与基于云的推荐人之间的协作,并从因果角度引入一种新颖的有效样本构造,以解决元控制者的数据集缺失问题。在反事实样本和扩展培训的基础上,在工业推荐方案中进行的广泛实验显示了在设备云协作中Meta控制器的承诺。
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自我监督的学习在表示视觉和文本数据的表示方面取得了巨大的成功。但是,当前的方法主要在经过良好策划的数据集中验证,这些数据集未显示现实世界的长尾分布。在损失的角度或模型观点中,重新平衡的重新平衡是为了考虑自我监督的长尾学习的最新尝试,类似于被监督的长尾学习中的范式。然而,没有标签的帮助,由于尾巴样品发现或启发式结构设计的限制,这些探索并未显示出预期的明显希望。与以前的作品不同,我们从替代角度(即数据角度)探索了这个方向,并提出了一种新颖的增强对比度学习(BCL)方法。具体而言,BCL利用深神经网络的记忆效果自动推动对比度学习中样本视图的信息差异,这更有效地增强了标签 - unaware环境中的长尾学习。对一系列基准数据集进行的广泛实验证明了BCL对几种最新方法的有效性。我们的代码可在https://github.com/mediabrain-sjtu/bcl上找到。
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受到深入学习的巨大成功通过云计算和边缘芯片的快速发展的影响,人工智能研究(AI)的研究已经转移到计算范例,即云计算和边缘计算。近年来,我们目睹了在云服务器上开发更高级的AI模型,以超越传统的深度学习模型,以造成模型创新(例如,变压器,净化家庭),训练数据爆炸和飙升的计算能力。但是,边缘计算,尤其是边缘和云协同计算,仍然在其初期阶段,因为由于资源受限的IOT场景,因此由于部署了非常有限的算法而导致其成功。在本调查中,我们对云和边缘AI进行系统审查。具体而言,我们是第一个设置云和边缘建模的协作学习机制,通过彻底的审查使能够实现这种机制的架构。我们还讨论了一些正在进行的先进EDGE AI主题的潜在和实践经验,包括预先训练模型,图形神经网络和加强学习。最后,我们讨论了这一领域的有希望的方向和挑战。
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对比度学习(CL)方法有效地学习数据表示,而无需标记监督,在该方法中,编码器通过单VS-MONY SOFTMAX跨透镜损失将每个正样本在多个负样本上对比。通过利用大量未标记的图像数据,在Imagenet上预先训练时,最近的CL方法获得了有希望的结果,这是一个具有均衡图像类的曲制曲线曲线集。但是,当对野外图像进行预训练时,它们往往会产生较差的性能。在本文中,为了进一步提高CL的性能并增强其对未经保育数据集的鲁棒性,我们提出了一种双重的CL策略,该策略将其内部查询的正(负)样本对比,然后才能决定多么强烈地拉动(推)。我们通过对比度吸引力和对比度排斥(CACR)意识到这一策略,这使得查询不仅发挥了更大的力量来吸引更遥远的正样本,而且可以驱除更接近的负面样本。理论分析表明,CACR通过考虑正/阴性样品的分布之间的差异来概括CL的行为,而正/负样品的分布通常与查询独立进行采样,并且它们的真实条件分布给出了查询。我们证明了这种独特的阳性吸引力和阴性排斥机制,这有助于消除在数据集的策划较低时尤其有益于数据及其潜在表示的统一先验分布的需求。对许多标准视觉任务进行的大规模大规模实验表明,CACR不仅在表示学习中的基准数据集上始终优于现有的CL方法,而且在对不平衡图像数据集进行预训练时,还表现出更好的鲁棒性。
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Learning with noisy labels is one of the hottest problems in weakly-supervised learning. Based on memorization effects of deep neural networks, training on small-loss instances becomes very promising for handling noisy labels. This fosters the state-of-the-art approach "Co-teaching" that cross-trains two deep neural networks using the small-loss trick. However, with the increase of epochs, two networks converge to a consensus and Co-teaching reduces to the self-training MentorNet. To tackle this issue, we propose a robust learning paradigm called Co-teaching+, which bridges the "Update by Disagreement" strategy with the original Co-teaching. First, two networks feed forward and predict all data, but keep prediction disagreement data only. Then, among such disagreement data, each network selects its small-loss data, but back propagates the small-loss data from its peer network and updates its own parameters. Empirical results on benchmark datasets demonstrate that Co-teaching+ is much superior to many state-of-theart methods in the robustness of trained models.
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Knowledge graph embedding (KGE), which maps entities and relations in a knowledge graph into continuous vector spaces, has achieved great success in predicting missing links in knowledge graphs. However, knowledge graphs often contain incomplete triples that are difficult to inductively infer by KGEs. To address this challenge, we resort to analogical inference and propose a novel and general self-supervised framework AnKGE to enhance KGE models with analogical inference capability. We propose an analogical object retriever that retrieves appropriate analogical objects from entity-level, relation-level, and triple-level. And in AnKGE, we train an analogy function for each level of analogical inference with the original element embedding from a well-trained KGE model as input, which outputs the analogical object embedding. In order to combine inductive inference capability from the original KGE model and analogical inference capability enhanced by AnKGE, we interpolate the analogy score with the base model score and introduce the adaptive weights in the score function for prediction. Through extensive experiments on FB15k-237 and WN18RR datasets, we show that AnKGE achieves competitive results on link prediction task and well performs analogical inference.
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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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Normalizing flow is a class of deep generative models for efficient sampling and density estimation. In practice, the flow often appears as a chain of invertible neural network blocks; to facilitate training, existing works have regularized flow trajectories and designed special network architectures. The current paper develops a neural ODE flow network inspired by the Jordan-Kinderleherer-Otto (JKO) scheme, which allows efficient block-wise training of the residual blocks and avoids inner loops of score matching or variational learning. As the JKO scheme unfolds the dynamic of gradient flow, the proposed model naturally stacks residual network blocks one-by-one, reducing the memory load and difficulty of performing end-to-end training of deep flow networks. We also develop adaptive time reparameterization of the flow network with a progressive refinement of the trajectory in probability space, which improves the model training efficiency and accuracy in practice. Using numerical experiments with synthetic and real data, we show that the proposed JKO-iFlow model achieves similar or better performance in generating new samples compared with existing flow and diffusion models at a significantly reduced computational and memory cost.
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Score-based diffusion models have captured widespread attention and funded fast progress of recent vision generative tasks. In this paper, we focus on diffusion model backbone which has been much neglected before. We systematically explore vision Transformers as diffusion learners for various generative tasks. With our improvements the performance of vanilla ViT-based backbone (IU-ViT) is boosted to be on par with traditional U-Net-based methods. We further provide a hypothesis on the implication of disentangling the generative backbone as an encoder-decoder structure and show proof-of-concept experiments verifying the effectiveness of a stronger encoder for generative tasks with ASymmetriC ENcoder Decoder (ASCEND). Our improvements achieve competitive results on CIFAR-10, CelebA, LSUN, CUB Bird and large-resolution text-to-image tasks. To the best of our knowledge, we are the first to successfully train a single diffusion model on text-to-image task beyond 64x64 resolution. We hope this will motivate people to rethink the modeling choices and the training pipelines for diffusion-based generative models.
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