This work explores an efficient approach to establish a foundational video-text model for tasks including open-vocabulary video classification, text-to-video retrieval, video captioning and video question-answering. We present VideoCoCa that reuses a pretrained image-text contrastive captioner (CoCa) model and adapt it to video-text tasks with minimal extra training. While previous works adapt image-text models with various cross-frame fusion modules (for example, cross-frame attention layer or perceiver resampler) and finetune the modified architecture on video-text data, we surprisingly find that the generative attentional pooling and contrastive attentional pooling layers in the image-text CoCa design are instantly adaptable to ``flattened frame embeddings'', yielding a strong zero-shot transfer baseline for many video-text tasks. Specifically, the frozen image encoder of a pretrained image-text CoCa takes each video frame as inputs and generates \(N\) token embeddings per frame for totally \(T\) video frames. We flatten \(N \times T\) token embeddings as a long sequence of frozen video representation and apply CoCa's generative attentional pooling and contrastive attentional pooling on top. All model weights including pooling layers are directly loaded from an image-text CoCa pretrained model. Without any video or video-text data, VideoCoCa's zero-shot transfer baseline already achieves state-of-the-art results on zero-shot video classification on Kinetics 400/600/700, UCF101, HMDB51, and Charades, as well as zero-shot text-to-video retrieval on MSR-VTT and ActivityNet Captions. We also explore lightweight finetuning on top of VideoCoCa, and achieve strong results on video question-answering (iVQA, MSRVTT-QA, MSVD-QA) and video captioning (MSR-VTT, ActivityNet, Youcook2). Our approach establishes a simple and effective video-text baseline for future research.
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Swarm learning (SL) is an emerging promising decentralized machine learning paradigm and has achieved high performance in clinical applications. SL solves the problem of a central structure in federated learning by combining edge computing and blockchain-based peer-to-peer network. While there are promising results in the assumption of the independent and identically distributed (IID) data across participants, SL suffers from performance degradation as the degree of the non-IID data increases. To address this problem, we propose a generative augmentation framework in swarm learning called SL-GAN, which augments the non-IID data by generating the synthetic data from participants. SL-GAN trains generators and discriminators locally, and periodically aggregation via a randomly elected coordinator in SL network. Under the standard assumptions, we theoretically prove the convergence of SL-GAN using stochastic approximations. Experimental results demonstrate that SL-GAN outperforms state-of-art methods on three real world clinical datasets including Tuberculosis, Leukemia, COVID-19.
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Proper functioning of connected and automated vehicles (CAVs) is crucial for the safety and efficiency of future intelligent transport systems. Meanwhile, transitioning to fully autonomous driving requires a long period of mixed autonomy traffic, including both CAVs and human-driven vehicles. Thus, collaboration decision-making for CAVs is essential to generate appropriate driving behaviors to enhance the safety and efficiency of mixed autonomy traffic. In recent years, deep reinforcement learning (DRL) has been widely used in solving decision-making problems. However, the existing DRL-based methods have been mainly focused on solving the decision-making of a single CAV. Using the existing DRL-based methods in mixed autonomy traffic cannot accurately represent the mutual effects of vehicles and model dynamic traffic environments. To address these shortcomings, this article proposes a graph reinforcement learning (GRL) approach for multi-agent decision-making of CAVs in mixed autonomy traffic. First, a generic and modular GRL framework is designed. Then, a systematic review of DRL and GRL methods is presented, focusing on the problems addressed in recent research. Moreover, a comparative study on different GRL methods is further proposed based on the designed framework to verify the effectiveness of GRL methods. Results show that the GRL methods can well optimize the performance of multi-agent decision-making for CAVs in mixed autonomy traffic compared to the DRL methods. Finally, challenges and future research directions are summarized. This study can provide a valuable research reference for solving the multi-agent decision-making problems of CAVs in mixed autonomy traffic and can promote the implementation of GRL-based methods into intelligent transportation systems. The source code of our work can be found at https://github.com/Jacklinkk/Graph_CAVs.
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神经隐式表示最近引起了机器人界的广泛关注,因为它们具有表现力,连续和紧凑。然而,基于稀疏激光雷达输入​​的城市规模增量隐式密集映射仍然是一个不足的挑战。为此,我们成功地构建了第一个城市规模的增量神经映射系统,该系统具有由环境级别和实例级建模组成的全景表示。给定稀疏发光点云流,它维护了一个动态生成模型,该模型将3D坐标映射到签名的距离字段(SDF)值。为了解决城市规模空间中不同级别的几何信息的困难,我们提出了一种定制的三层抽样策略,以动态采样全球,本地和近乎表面的域。同时,为了实现高保真度映射,引入了特定于类别的先验,以更好地对几何细节进行建模,从而导致全景表示。我们使用定量和定性结果评估了公共Semantickitti数据集,并证明了新提出的三层抽样策略和泛型表示的重要性。代码和数据将公开可用。
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图像中的3D重建在虚拟现实和自动驾驶中具有广泛的应用,在此精确要求非常高。通过利用多层感知,在神经辐射场(NERF)中进行的突破性研究已大大提高了3D对象的表示质量。后来的一些研究通过建立截短的签名距离场(TSDF)改善了NERF,但仍遭受3D重建中表面模糊的问题。在这项工作中,通过提出一种新颖的3D形状表示方式Omninerf来解决这种表面歧义。它基于训练Omni方向距离场(ODF)和神经辐射场的混合隐式场,用全向信息代替NERF中的明显密度。此外,我们在深度图上介绍了其他监督,以进一步提高重建质量。该提出的方法已被证明可以有效处理表面重建边缘的NERF缺陷,从而提供了更高质量的3D场景重建结果。
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神经辐射场(NERF)在代表具有高分辨率细节和有效记忆的复杂3D场景方面取得了巨大成功。然而,当前基于NERF的姿势估计量没有初始姿势预测,并且在优化过程中易于局部优势。在本文中,我们介绍了纬度:全球定位,具有截短的动态低通滤波器,该过滤器引入了城市规模的NERF中的两阶段定位机制。在识别阶段,我们通过训练有素的NERFS生成的图像来训练回归器,该图像为全球本地化提供了初始值。在姿势优化阶段,我们通过直接优化切线平面上的姿势来最大程度地减少观察到的图像之间的残差和渲染图像。为了避免收敛到局部最优,我们引入了一个截短的动态低通滤波器(TDLF),以进行粗到细小的姿势注册。我们在合成和现实世界中评估了我们的方法,并显示了其在大规模城市场景中高精度导航的潜在应用。代码和数据将在https://github.com/jike5/latitude上公开获取。
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域的概括旨在学习一个可以很好地概括在看不见的测试数据集(即分布数据集)上的模型,该数据与培训数据集不同。为了解决计算机视觉中的领域概括,我们将损失景观理论引入该领域。具体而言,我们从损失景观的角度从四个方面(包括骨干,正则化,训练范式和学习率)引起了深度学习模型的概括能力。我们通过进行广泛的消融研究和可视化来验证有关NICO ++,PAC和VLCS数据集的提议理论。此外,我们将该理论应用于ECCV 2022 NICO挑战1,并在不使用任何域不变方法的情况下获得第三名。
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我们介绍了自回归文本到图像(Parti)模型的途径,该模型生成高保真的影像图像并支持涉及复杂组成和世界知识的内容丰富的合成。 Parti将文本对图像生成视为类似于机器翻译的序列到序列建模问题,图像令牌的序列是目标输出,而不是其他语言的文本令牌。这种策略自然可以利用大型语言模型的先前工作,通过扩展数据和模型尺寸,能力和性能的持续进展。我们的方法很简单:首先,Parti使用基于变压器的图像令牌VIT-VQGAN将图像编码为离散令牌的序列。其次,我们通过将编码器二次变压器模型缩放到20B参数来实现一致的质量改进,其新的最新零弹药FID得分为7.23,而MS-Coco的FIDED得分为3.22。我们对本地化叙述以及党的详细分析(P2),这是1600多个英语提示的新的整体基准,证明了Parti在各种类别和难度方面的有效性。我们还探索并突出了我们的模型的局限性,以定义和体现关注重点领域以进一步改进。有关高分辨率图像,请参见https://parti.research.google/。
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语言模型既展示了定量的改进,又展示了新的定性功能,随着规模的增加。尽管它们具有潜在的变革性影响,但这些新能力的特征却很差。为了为未来的研究提供信息,为破坏性的新模型能力做准备,并改善社会有害的效果,至关重要的是,我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战,我们介绍了超越模仿游戏基准(Big Bench)。 Big Bench目前由204个任务组成,由132家机构的442位作者贡献。任务主题是多样的,从语言学,儿童发展,数学,常识性推理,生物学,物理学,社会偏见,软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号,Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为,跨越了数百万到数十亿个参数。此外,一个人类专家评估者团队执行了所有任务,以提供强大的基准。研究结果包括:模型性能和校准都随规模改善,但绝对的术语(以及与评估者的性能相比);在模型类中的性能非常相似,尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分,而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标;社交偏见通常会随着含糊不清的环境而随着规模而增加,但这可以通过提示来改善。
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探索大规模预处理的基础模型对计算机视觉具有重大兴趣,因为这些模型可以快速转移到许多下游任务中。本文介绍了对比字幕(COCA),这是一种极简主义的设计,旨在为图像文本编码器编码器基础模型预算与对比度损失和字幕损失,从而从剪辑和诸如simvlm之类的生成方法之类的对比方法中包含模型能力。与所有解码器层都参与编码器输出的标准编码器 - 模块变压器相反,可口可乐省略了解码器层的上半部分的交叉注意,以编码单峰文本表示,并串联到剩余的解码器层,这些解码器与图像编码器相交的解码器层多模式图像文本表示。除了对多模态解码器输出的字幕损失外,我们还应用了单峰图像和文本嵌入之间的对比损失,该输出可以预测文本令牌自动加压。通过共享相同的计算图,可以用最小的开销有效地计算两个培训目标。可口可乐是端到端和从头开始的网络尺度alt-text数据和带注释的图像,通过将所有标签视为文本,无缝地统一自然语言监督以进行表示。从经验上讲,可口可乐通过零拍传输或在广泛的下游任务上进行零摄像转移或最少的特定任务适应,跨越视觉识别(Imagenet,Kinetics-400/600/700,瞬间, ),交叉模式检索(MSCOCO,FLICKR30K,MSR-VTT),多模式理解(VQA,SNLI-VE,NLVR2)和图像字幕(MSCOCO,NOCAPS)。值得注意的是,在Imagenet分类方面,COCA获得了86.3%的TOP-1准确性,带有冷冻编码器和学习的分类头90.6%,以及带有填充编码器的Imagenet上的新最先进的91.0%Top-1 Top-1精度。
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