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.
translated by 谷歌翻译
Most cross-device federated learning (FL) studies focus on the model-homogeneous setting where the global server model and local client models are identical. However, such constraint not only excludes low-end clients who would otherwise make unique contributions to model training but also restrains clients from training large models due to on-device resource bottlenecks. In this work, we propose FedRolex, a partial training (PT)-based approach that enables model-heterogeneous FL and can train a global server model larger than the largest client model. At its core, FedRolex employs a rolling sub-model extraction scheme that allows different parts of the global server model to be evenly trained, which mitigates the client drift induced by the inconsistency between individual client models and server model architectures. We show that FedRolex outperforms state-of-the-art PT-based model-heterogeneous FL methods (e.g. Federated Dropout) and reduces the gap between model-heterogeneous and model-homogeneous FL, especially under the large-model large-dataset regime. In addition, we provide theoretical statistical analysis on its advantage over Federated Dropout and evaluate FedRolex on an emulated real-world device distribution to show that FedRolex can enhance the inclusiveness of FL and boost the performance of low-end devices that would otherwise not benefit from FL. Our code is available at https://github.com/MSU-MLSys-Lab/FedRolex.
translated by 谷歌翻译
MetaFormer, the abstracted architecture of Transformer, has been found to play a significant role in achieving competitive performance. In this paper, we further explore the capacity of MetaFormer, again, without focusing on token mixer design: we introduce several baseline models under MetaFormer using the most basic or common mixers, and summarize our observations as follows: (1) MetaFormer ensures solid lower bound of performance. By merely adopting identity mapping as the token mixer, the MetaFormer model, termed IdentityFormer, achieves >80% accuracy on ImageNet-1K. (2) MetaFormer works well with arbitrary token mixers. When specifying the token mixer as even a random matrix to mix tokens, the resulting model RandFormer yields an accuracy of >81%, outperforming IdentityFormer. Rest assured of MetaFormer's results when new token mixers are adopted. (3) MetaFormer effortlessly offers state-of-the-art results. With just conventional token mixers dated back five years ago, the models instantiated from MetaFormer already beat state of the art. (a) ConvFormer outperforms ConvNeXt. Taking the common depthwise separable convolutions as the token mixer, the model termed ConvFormer, which can be regarded as pure CNNs, outperforms the strong CNN model ConvNeXt. (b) CAFormer sets new record on ImageNet-1K. By simply applying depthwise separable convolutions as token mixer in the bottom stages and vanilla self-attention in the top stages, the resulting model CAFormer sets a new record on ImageNet-1K: it achieves an accuracy of 85.5% at 224x224 resolution, under normal supervised training without external data or distillation. In our expedition to probe MetaFormer, we also find that a new activation, StarReLU, reduces 71% FLOPs of activation compared with GELU yet achieves better performance. We expect StarReLU to find great potential in MetaFormer-like models alongside other neural networks.
translated by 谷歌翻译
在这项工作中,我们解决了共同跟踪手对象姿势并从野外深度点云序列重建形状的具有挑战性,HandTrackNet,以估计框架间的手动运动。我们的HandTrackNet提出了一个新型的手姿势构成典型化模块,以简化跟踪任务,从而产生准确且稳健的手工关节跟踪。然后,我们的管道通过将预测的手关节转换为基于模板的参数手模型mano来重建全手。对于对象跟踪,我们设计了一个简单而有效的模块,该模块从第一帧估算对象SDF并执行基于优化的跟踪。最后,采用联合优化步骤执行联合手和物体推理,从而减轻了闭塞引起的歧义并进一步完善了手姿势。在训练过程中,整个管道仅看到纯粹的合成数据,这些数据与足够的变化并通过深度模拟合成,以易于概括。整个管道与概括差距有关,因此可以直接传输到真实的野外数据。我们在两个真实的手对象交互数据集上评估我们的方法,例如HO3D和DEXYCB,没有任何填充。我们的实验表明,所提出的方法显着优于先前基于深度的手和对象姿势估计和跟踪方法,以9 fps的帧速率运行。
translated by 谷歌翻译
知识图的归纳链路预测旨在预测未见实体之间的缺失联系,而那些未在训练阶段显示的实体。大多数以前的作品都学习实体的特定实体嵌入,这些实体无法处理看不见的实体。最近的几种方法利用封闭子图来获得归纳能力。但是,所有这些作品仅在没有完整的邻近关系的情况下考虑子图的封闭部分,这导致了忽略部分邻近关系的问题,并且很难处理稀疏的子图。为了解决这个问题,我们提出了SNRI子图邻近关系Infomax,它足够从两个方面利用完整的相邻关系:节点特征的相邻关系特征和稀疏子图的相邻关系路径。为了进一步以全球方式建模邻近关系,我们对知识图进行创新的相互信息(MI)最大化。实验表明,SNRI在归纳链路预测任务上的大幅度优于现有的最新方法,并验证以全局方式探索完整的邻近关系的有效性,以表征节点特征和在稀疏子分类上的理由。
translated by 谷歌翻译
神经网络二进制通过将其权重和激活量化为1位来加速深层模型。但是,二进制神经网络(BNN)与其完整精确(FP)对应物之间仍然存在巨大的性能差距。由于早期作品中权重二进制引起的量化误差已减少,因此激活二进化成为进一步提高准确性的主要障碍。 BNN表征了独特而有趣的结构,其中二进制和潜在的fp激活存在于同一正向通行证中(\ textit {i.e。} $ \ text {binarize}(\ mathbf {a} _f {a} _f)= \ mathbf {a a} _b $) 。为了减轻从FP到二元激活的二进化操作引起的信息降解,我们在通过互信息(MI)最大化的镜头训练BNN时建立了一种新颖的对比学习框架。将MI作为指标引入,以衡量二进制和FP激活之间共享的信息,这有助于对比度学习。具体而言,通过从相同输入样品中拉出二进制和FP激活的正对,以及从不同样品中推动负面对(负面对数的数量可以大大),从而极大地增强了BNN的表示能力。这使下游任务不仅有益于分类,而且还受益于分类和深度估计,〜\ textit {etc}。实验结果表明,我们的方法可以作为现有最新二元方法的堆积模块实现NYUD-V2的能力。
translated by 谷歌翻译
在本文中,我们提出了一种名为Matryoshka的新型内部攻击,该攻击采用无关紧要的计划与公开的DNN模型作为覆盖多个秘密模型的载体模型,以记住存储在本地数据中心中的私人ML数据的功能。我们没有将载体模型的参数视为位字符串并应用常规隐志,而是设计了一种新型参数共享方法,该方法利用了载体模型的学习能力来隐藏信息。同时实现Matryoshka:(i)高容量 - Matryoshka几乎没有实用性损失载体模型,可以隐藏一个26倍较大的秘密模型或8个跨越载体模型中不同应用程序域的不同体系结构的秘密模型,这两个模型都不能是使用现有的隐志技术完成; (ii)解码效率 - 一旦下载了已发布的运营商模型,外部颜色可以将隐藏的模型独家解码,只有几个整数秘密和隐藏模型体系结构的知识; (iii)有效性 - 此外,几乎所有恢复的模型的性能都与私人数据独立培训一样; (iv)鲁棒性 - 自然会实施信息冗余,以在出版前对载体上的常见后处理技术实现弹性; (v)秘密性 - 具有不同先验知识水平的模型检查员几乎不能将载体模型与正常模型区分开。
translated by 谷歌翻译
学习协作对于多机构增强学习(MARL)至关重要。以前的作品通过最大化代理行为的相关性来促进协作,该行为的相关性通常以不同形式的相互信息(MI)为特征。但是,我们揭示了次最佳的协作行为,也出现了强烈的相关性,并且简单地最大化MI可以阻碍学习的学习能力。为了解决这个问题,我们提出了一个新颖的MARL框架,称为“渐进式信息协作(PMIC)”,以进行更有效的MI驱动协作。 PMIC使用全球国家和联合行动之间MI测量的新协作标准。基于此标准,PMIC的关键思想是最大程度地提高与优越的协作行为相关的MI,并最大程度地减少与下等方面相关的MI。这两个MI目标通过促进更好的合作,同时避免陷入次级优势,从而扮演互补的角色。与其他算法相比,在各种MARL基准测试的实验表明,PMIC的表现出色。
translated by 谷歌翻译
视频理解需要在多种时空分辨率下推理 - 从短的细粒度动作到更长的持续时间。虽然变压器架构最近提出了最先进的,但它们没有明确建模不同的时空分辨率。为此,我们为视频识别(MTV)提供了多视图变压器。我们的模型由单独的编码器组成,表示输入视频的不同视图,以横向连接,以跨视图熔断信息。我们对我们的模型提供了彻底的消融研究,并表明MTV在一系列模型尺寸范围内的准确性和计算成本方面始终如一地表现优于单视对应力。此外,我们在五个标准数据集上实现最先进的结果,并通过大规模预制来进一步提高。我们将释放代码和备用检查点。
translated by 谷歌翻译
作为一种流行的几何表示,点云在3D视觉中引起了很多关注,导致自动驾驶和机器人中的许多应用。在点云上学习一个重要的尚未解决的问题是,如果使用不同的过程或使用不同的传感器捕获,则相同对象的点云可以具有显着的几何变化。这些不一致地诱导域间隙,使得在一个域上培训的神经网络可能无法概括他人。减少域间隙的典型技术是执行逆势训练,以便特征空间中的点云可以对齐。然而,对抗性训练易于落入退化的局部最小值,导致负适应性收益。在这里,我们提出了一种简单而有效的方法,可以通过采用学习几何感知含义的自我监督任务来提出对点云的无监督域适应的方法,这在一次拍摄中扮演两个关键角色。首先,通过对下游任务的隐式表示保留点云中的几何信息。更重要的是,可以在隐式空间中有效地学习域特定变体。我们还提出了一种自适应策略,以计算由于在实践中缺乏形状模型而计算任意点云的无符号距离场。当结合任务丢失时,所提出的优先表现出最先进的无监督域适应方法,依赖于对抗域对齐和更复杂的自我监督任务。我们的方法在PointDA-10和Graspnet数据集上进行评估。代码和培训的型号将公开可用。
translated by 谷歌翻译