Federated learning has attracted increasing attention with the emergence of distributed data. While extensive federated learning algorithms have been proposed for the non-convex distributed problem, the federated learning in practice still faces numerous challenges, such as the large training iterations to converge since the sizes of models and datasets keep increasing, and the lack of adaptivity by SGD-based model updates. Meanwhile, the study of adaptive methods in federated learning is scarce and existing works either lack a complete theoretical convergence guarantee or have slow sample complexity. In this paper, we propose an efficient adaptive algorithm (i.e., FAFED) based on the momentum-based variance reduced technique in cross-silo FL. We first explore how to design the adaptive algorithm in the FL setting. By providing a counter-example, we prove that a simple combination of FL and adaptive methods could lead to divergence. More importantly, we provide a convergence analysis for our method and prove that our algorithm is the first adaptive FL algorithm to reach the best-known samples $O(\epsilon^{-3})$ and $O(\epsilon^{-2})$ communication rounds to find an $\epsilon$-stationary point without large batches. The experimental results on the language modeling task and image classification task with heterogeneous data demonstrate the efficiency of our algorithms.
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实现人类水平的灵活性是机器人技术中的重要开放问题。但是,即使在婴儿级别,灵巧的手动操纵任务也是通过增强学习(RL)的挑战。困难在于高度的自由度和异质因素(例如手指关节)之间所需的合作。在这项研究中,我们提出了双人灵感手基准(BI-DEXHANDS),这是一种模拟器,涉及两只灵巧的手,其中包含数十只双人操纵任务和数千个目标对象。具体而言,根据认知科学文献,BI-DEXHANDS中的任务旨在匹配不同级别的人类运动技能。我们在ISSAC体育馆里建造了Bi-Dexhands;这可以实现高效的RL培训,仅在一个NVIDIA RTX 3090中达到30,000+ fps。我们在不同的设置下为流行的RL算法提供了全面的基准;这包括单代理/多代理RL,离线RL,多任务RL和META RL。我们的结果表明,PPO类型的上车算法可以掌握简单的操纵任务,该任务等效到48个月的人类婴儿(例如,捕获飞行的物体,打开瓶子),而多代理RL可以进一步帮助掌握掌握需要熟练的双人合作的操作(例如,举起锅,堆叠块)。尽管每个任务都取得了成功,但在获得多个操纵技能方面,现有的RL算法无法在大多数多任务和少量学习设置中工作,这需要从RL社区进行更实质性的发展。我们的项目通过https://github.com/pku-marl/dexteroushands开放。
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Domain adaptation for Cross-LiDAR 3D detection is challenging due to the large gap on the raw data representation with disparate point densities and point arrangements. By exploring domain-invariant 3D geometric characteristics and motion patterns, we present an unsupervised domain adaptation method that overcomes above difficulties. First, we propose the Spatial Geometry Alignment module to extract similar 3D shape geometric features of the same object class to align two domains, while eliminating the effect of distinct point distributions. Second, we present Temporal Motion Alignment module to utilize motion features in sequential frames of data to match two domains. Prototypes generated from two modules are incorporated into the pseudo-label reweighting procedure and contribute to our effective self-training framework for the target domain. Extensive experiments show that our method achieves state-of-the-art performance on cross-device datasets, especially for the datasets with large gaps captured by mechanical scanning LiDARs and solid-state LiDARs in various scenes. Project homepage is at https://github.com/4DVLab/CL3D.git
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智能机器之间合作的必要性已在人工智能(AI)研究界普及了合作的多代理增强学习(MARL)。但是,许多研究的努力一直集中在开发实用的MARL算法上,其有效性仅在经验上进行了研究,从而缺乏理论保证。正如最近的研究所表明的那样,MARL方法通常达到奖励单调性或收敛性次优的性能。为了解决这些问题,在本文中,我们介绍了一个名为异质的镜像学习(HAML)的新颖框架,该框架为MARL算法设计提供了一个通用模板。我们证明,源自HAML模板的算法满足了关节奖励的单调改善的所需特性以及与NASH平衡的收敛性。我们通过证明当前最新的合作社Marl算法,HATRPO和HAPKO实际上是HAML实例,来验证HAML的实用性。接下来,作为我们理论的自然结果,我们提出了两种众所周知的RL算法HAA2C(用于A2C)和HADDPG(用于DDPG)的HAML扩展,并证明了它们针对StarcraftII和多代理Mujoco任务的强大基准的有效性。
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提出了一种新型可重构智能表面辅助的多机器人网络,其中多个移动机器人通过非正交多重访问(NOMA)提供了多个移动机器人(AP)。目的是通过共同优化机器人的轨迹和NOMA解码顺序,RIS的相移系数以及AP的功率分配,从而最大化多机器人系统的整个轨迹的总和率机器人的位置和每个机器人的服务质量(QoS)。为了解决这个问题,提出了一个集成的机器学习(ML)方案,该方案结合了长期记忆(LSTM) - 自动进取的集成移动平均线(ARIMA)模型和Duel Duel Double Deep Q-network(D $^{3} $ QN)算法。对于机器人的初始和最终位置预测,LSTM-ARIMA能够克服非平稳和非线性数据序列的梯度销售问题。为了共同确定相移矩阵和机器人的轨迹,调用D $^{3} $ qn用于解决动作值高估的问题。基于提议的方案,每个机器人都基于整个轨迹的最大总和率持有全局最佳轨迹,该轨迹揭示了机器人为整个轨迹设计追求长期福利。数值结果表明:1)LSTM-ARIMA模型提供了高精度预测模型; 2)提出的d $^{3} $ qn算法可以实现快速平均收敛; 3)具有较高分辨率位的RI提供的轨迹比率比低分辨率比特更大; 4)与RIS AID的正交对应物相比,RIS-NOMA网络的网络性能卓越。
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近年来,基于梯度的Meta-RL(GMRL)方法在发现一个单一任务的有效在线超参数中取得了显着的成功(XU等,2018)或学习多任务转移学习的良好初始化(Finn等人。 ,2017)。尽管有经验的成功,但经常被忽视,通过香草背交计算元梯度是不明定义的。在本文中,我们认为许多现有的MGRL方法采用的随机元梯度估计实际上是偏见的;偏差来自两个来源:1)在组成优化问题的结构中自然的成分偏差和2)由直接自动分化引起的多步粗糙估计的偏差。为了更好地了解元梯度偏差,我们首先执行其研究,以量化每个研究。我们首先为现有的GMRL算法提供统一的推导,然后理论上分析偏差和现有梯度估计方法的方差。了解偏见的基本原则,我们提出了两种缓解解决方案,基于脱离政策校正和多步理估计技术。已经进行了综合烧蚀研究,结果显示:(1)当与不同估计器/示例大小/步骤和学习率相结合时,它们的存在以及它们如何影响元梯度估计。 (2)这些缓解方法对Meta梯度估计的有效性,从而最终回报率两种实用的Meta-RL算法:Lola-Dice和Meta-梯度加固学习。
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在解决双球员零和游戏时,多代理强化学习(MARL)算法通常会在每次迭代时创造代理人群,在每次迭代时,将被发现为对对手人口对混合的最佳响应。在这样的过程中,“遵循”(即对手混合物)和“如何击败它们”(即寻找最佳响应)的更新规则是由手动开发的游戏理论原则基础,如虚构的游戏和双倍甲骨文。在本文中,我们介绍了一种新颖的框架 - 神经自动课程(NAC) - 利用元梯度下降来自动化学习更新规则的发现,而无明确的人类设计。具体而言,我们通过优化子程序参数通过神经网络和最佳响应模块参数化对手选择模块,并通过与游戏引擎的交互仅更新其参数,其中播放器旨在最大限度地减少其利用性。令人惊讶的是,即使没有人类的设计,发现的Marl算法也可以通过基于最先进的人口的游戏,在技能游戏,可微分的乐透,不转化的混合物游戏中实现竞争或更好的性能,实现竞争或更好的性能。迭代匹配的便士和kuhn扑克。此外,我们表明NAC能够从小型游戏到大型游戏,例如Kuhn Poker培训,在LEDUC扑克上表现优于PSRO。我们的工作激发了一个未来的未来方向,以完全从数据发现一般的Marl算法。
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A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
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Weakly-supervised object localization aims to indicate the category as well as the scope of an object in an image given only the image-level labels. Most of the existing works are based on Class Activation Mapping (CAM) and endeavor to enlarge the discriminative area inside the activation map to perceive the whole object, yet ignore the co-occurrence confounder of the object and context (e.g., fish and water), which makes the model inspection hard to distinguish object boundaries. Besides, the use of CAM also brings a dilemma problem that the classification and localization always suffer from a performance gap and can not reach their highest accuracy simultaneously. In this paper, we propose a casual knowledge distillation method, dubbed KD-CI-CAM, to address these two under-explored issues in one go. More specifically, we tackle the co-occurrence context confounder problem via causal intervention (CI), which explores the causalities among image features, contexts, and categories to eliminate the biased object-context entanglement in the class activation maps. Based on the de-biased object feature, we additionally propose a multi-teacher causal distillation framework to balance the absorption of classification knowledge and localization knowledge during model training. Extensive experiments on several benchmarks demonstrate the effectiveness of KD-CI-CAM in learning clear object boundaries from confounding contexts and addressing the dilemma problem between classification and localization performance.
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Witnessing the impressive achievements of pre-training techniques on large-scale data in the field of computer vision and natural language processing, we wonder whether this idea could be adapted in a grab-and-go spirit, and mitigate the sample inefficiency problem for visuomotor driving. Given the highly dynamic and variant nature of the input, the visuomotor driving task inherently lacks view and translation invariance, and the visual input contains massive irrelevant information for decision making, resulting in predominant pre-training approaches from general vision less suitable for the autonomous driving task. To this end, we propose PPGeo (Policy Pre-training via Geometric modeling), an intuitive and straightforward fully self-supervised framework curated for the policy pretraining in visuomotor driving. We aim at learning policy representations as a powerful abstraction by modeling 3D geometric scenes on large-scale unlabeled and uncalibrated YouTube driving videos. The proposed PPGeo is performed in two stages to support effective self-supervised training. In the first stage, the geometric modeling framework generates pose and depth predictions simultaneously, with two consecutive frames as input. In the second stage, the visual encoder learns driving policy representation by predicting the future ego-motion and optimizing with the photometric error based on current visual observation only. As such, the pre-trained visual encoder is equipped with rich driving policy related representations and thereby competent for multiple visuomotor driving tasks. Extensive experiments covering a wide span of challenging scenarios have demonstrated the superiority of our proposed approach, where improvements range from 2% to even over 100% with very limited data. Code and models will be available at https://github.com/OpenDriveLab/PPGeo.
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