在本文中,我们从经验上研究了如何充分利用低分辨率框架以进行有效的视频识别。现有方法主要集中于开发紧凑的网络或减轻视频输入的时间冗余以提高效率,而压缩框架分辨率很少被认为是有希望的解决方案。一个主要问题是低分辨率帧的识别准确性不佳。因此,我们首先分析低分辨率帧上性能降解的根本原因。我们的主要发现是,降级的主要原因不是在下采样过程中的信息丢失,而是网络体系结构和输入量表之间的不匹配。通过知识蒸馏(KD)的成功,我们建议通过跨分辨率KD(RESKD)弥合网络和输入大小之间的差距。我们的工作表明,RESKD是一种简单但有效的方法,可以提高低分辨率帧的识别精度。没有铃铛和哨子,RESKD在四个大规模基准数据集(即ActivityNet,FCVID,Mini-Kinetics,sopeings soseings ossings v2)上,就效率和准确性上的所有竞争方法都大大超过了所有竞争方法。此外,我们广泛地展示了其对最先进的体系结构(即3D-CNN和视频变压器)的有效性,以及对超低分辨率帧的可扩展性。结果表明,RESKD可以作为最先进视频识别的一般推理加速方法。我们的代码将在https://github.com/cvmi-lab/reskd上找到。
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图形神经网络(GNN)是具有无核数据的应用的有前途的方法。但是,具有数亿节点的大规模图上的培训GNN既是资源又是耗时的。与DNN不同,GNN通常具有更大的内存足迹,因此GPU内存能力和PCIE带宽是GNN培训中的主要资源瓶颈。为了解决此问题,我们提出分叉:一种图形量化方法,通过显着减少内存足迹和PCIE带宽要求来加速GNN训练,以便GNN可以充分利用GPU计算功能。我们的关键见解是,与DNN不同,GNN不太容易发生量化引起的输入特征的信息丢失。我们确定图形特征量化中的主要准确性影响因素,从理论上证明,分叉训练会收敛到网络,在该网络中,损失在未压缩网络的最佳损失的$ \ epsilon $之内。我们使用几种流行的GNN模型和数据集对分叉进行了广泛的评估,包括最大的公共图数据集MAG240M上的图形。结果表明,分叉达到30以上的压缩率,并在边际准确性损失的情况下提高了GNN训练速度200%-320%。特别是,分叉在一小时内仅使用四个GPU在MAG240M上的训练图来实现记录。
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尽管近年来从CT/MRI扫描中自动腹部多器官分割取得了很大进展,但由于缺乏各种临床方案的大规模基准,对模型的能力的全面评估受到阻碍。收集和标记3D医学数据的高成本的限制,迄今为止的大多数深度学习模型都由具有有限数量的感兴趣或样品器官的数据集驱动,这仍然限制了现代深层模型的力量提供各种方法的全面且公平的估计。为了减轻局限性,我们提出了AMO,这是一个大规模,多样的临床数据集,用于腹部器官分割。 AMOS提供了从多中心,多供应商,多模式,多相,多疾病患者收集的500 CT和100次MRI扫描,每个患者均具有15个腹部器官的体素级注释,提供了具有挑战性的例子,并提供了挑战性的例子和测试结果。在不同的目标和场景下研究健壮的分割算法。我们进一步基准了几种最先进的医疗细分模型,以评估此新挑战性数据集中现有方法的状态。我们已公开提供数据集,基准服务器和基线,并希望激发未来的研究。信息可以在https://amos22.grand-challenge.org上找到。
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DataSet Shift在信用评分场景中很常见,并且培训数据分发与实际需要预测的数据之间的不一致可能导致模型性能不佳。但是,大多数当前研究都没有考虑到这一点,并且当培训模型时,它们直接在不同时间段中混合数据。这带来了大约两个问题。首先,存在数据泄漏的风险,即,使用未来的数据来预测过去。这可能导致离线验证的导致膨胀,但在实际应用中会导致不令人满意的结果。其次,在不同的时间段中,宏观经济环境和风险控制策略可能是不同的,借款人的行为模式也可能发生变化。具有过去数据培训的模型可能不适用于最近的阶段。因此,我们提出了一种基于对抗性验证的方法来缓解信用评分场景中的数据集转变问题。在该方法中,选择具有最接近预测数据的分布的部分训练设置样本用于通过对抗验证进行交叉验证,以确保训练模型对预测样本的泛化性能。另外,通过简单的拼接方法,与测试数据分发不一致的训练数据中的样本也也涉及交叉验证的培训过程,这充分利用了所有数据并进一步提高了模型性能。为了验证所提出的方法的有效性,通过贷款俱乐部提供的数据进行了具有若干其他数据分离方法的比较实验。实验结果表明,数据集转变在信用评分领域的重要性以及所提出的方法的优势。
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联合医疗关系提取是指由单个模型从医学文本中提取由实体和关系组成的三元组。解决方案之一是将此任务转换为顺序标记任务。但是,在现有的作品中,以线性方式表示和标记三元组的方法失败了,而将三元组组织为图形的方法面临着大量计算工作的挑战。在本文中,受到医学文本中类似树状的关系结构的启发,我们提出了一个名为“双向树”标签(BITT)的新颖方案,将医疗关系三元组成两条两条二进制树,并将树转换为单词级别的标签序列。基于BITT方案,我们开发了一个联合关系提取模型,以预测BITT标签并进一步提取医疗三元三元。我们的模型在两个医疗数据集上的最佳基准在F1分中优于2.0 \%和2.5 \%。更重要的是,我们的BITT方案的模型还可以在其他域的三个公共数据集中获得有希望的结果。
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Recent work has shown that fine-tuning large pre-trained language models on a collection of tasks described via instructions, a.k.a. instruction-tuning, improves their zero and few-shot generalization to unseen tasks. However, there is a limited understanding of the performance trade-offs of different decisions made during the instruction-tuning process. These decisions include the scale and diversity of the instruction-tuning benchmark, different task sampling strategies, fine-tuning with and without demonstrations, training using specialized datasets for reasoning and dialogue, and finally, the fine-tuning objectives themselves. In this paper, we characterize the effect of instruction-tuning decisions on downstream task performance when scaling both model and benchmark sizes. To this end, we create OPT-IML Bench: a large benchmark for Instruction Meta-Learning (IML) of 2000 NLP tasks consolidated into task categories from 8 existing benchmarks, and prepare an evaluation framework to measure three types of model generalizations: to tasks from fully held-out categories, to held-out tasks from seen categories, and to held-out instances from seen tasks. Through the lens of this framework, we first present insights about instruction-tuning decisions as applied to OPT-30B and further exploit these insights to train OPT-IML 30B and 175B, which are instruction-tuned versions of OPT. OPT-IML demonstrates all three generalization abilities at both scales on four different evaluation benchmarks with diverse tasks and input formats -- PromptSource, FLAN, Super-NaturalInstructions, and UnifiedSKG. Not only does it significantly outperform OPT on all benchmarks but is also highly competitive with existing models fine-tuned on each specific benchmark. We release OPT-IML at both scales, together with the OPT-IML Bench evaluation framework.
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Current large language models can perform reasonably well on complex tasks that require step-by-step reasoning with few-shot learning. Are these models applying reasoning skills they have learnt during pre-training and reason outside of their training context, or are they simply memorizing their training corpus at finer granularity and have learnt to better understand their context? To tease apart these possibilities, we introduce ALERT, a benchmark and suite of analyses for assessing language models' reasoning ability comparing pre-trained and finetuned models on complex tasks that require reasoning skills to solve. ALERT provides a test bed to asses any language model on fine-grained reasoning skills, which spans over 20 datasets and covers 10 different reasoning skills. We leverage ALERT to further investigate the role of finetuning. With extensive empirical analysis we find that language models learn more reasoning skills such as textual entailment, abductive reasoning, and analogical reasoning during finetuning stage compared to pretraining state. We also find that when language models are finetuned they tend to overfit to the prompt template, which hurts the robustness of models causing generalization problems.
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Recent progress on vision-language foundation models have brought significant advancement to building general-purpose robots. By using the pre-trained models to encode the scene and instructions as inputs for decision making, the instruction-conditioned policy can generalize across different objects and tasks. While this is encouraging, the policy still fails in most cases given an unseen task or environment. To adapt the policy to unseen tasks and environments, we explore a new paradigm on leveraging the pre-trained foundation models with Self-PLAY and Self-Describe (SPLAYD). When deploying the trained policy to a new task or a new environment, we first let the policy self-play with randomly generated instructions to record the demonstrations. While the execution could be wrong, we can use the pre-trained foundation models to accurately self-describe (i.e., re-label or classify) the demonstrations. This automatically provides new pairs of demonstration-instruction data for policy fine-tuning. We evaluate our method on a broad range of experiments with the focus on generalization on unseen objects, unseen tasks, unseen environments, and sim-to-real transfer. We show SPLAYD improves baselines by a large margin in all cases. Our project page is available at https://geyuying.github.io/SPLAYD/
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This paper proposes a deep recurrent Rotation Averaging Graph Optimizer (RAGO) for Multiple Rotation Averaging (MRA). Conventional optimization-based methods usually fail to produce accurate results due to corrupted and noisy relative measurements. Recent learning-based approaches regard MRA as a regression problem, while these methods are sensitive to initialization due to the gauge freedom problem. To handle these problems, we propose a learnable iterative graph optimizer minimizing a gauge-invariant cost function with an edge rectification strategy to mitigate the effect of inaccurate measurements. Our graph optimizer iteratively refines the global camera rotations by minimizing each node's single rotation objective function. Besides, our approach iteratively rectifies relative rotations to make them more consistent with the current camera orientations and observed relative rotations. Furthermore, we employ a gated recurrent unit to improve the result by tracing the temporal information of the cost graph. Our framework is a real-time learning-to-optimize rotation averaging graph optimizer with a tiny size deployed for real-world applications. RAGO outperforms previous traditional and deep methods on real-world and synthetic datasets. The code is available at https://github.com/sfu-gruvi-3dv/RAGO
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Stochastic gradients closely relate to both optimization and generalization of deep neural networks (DNNs). Some works attempted to explain the success of stochastic optimization for deep learning by the arguably heavy-tail properties of gradient noise, while other works presented theoretical and empirical evidence against the heavy-tail hypothesis on gradient noise. Unfortunately, formal statistical tests for analyzing the structure and heavy tails of stochastic gradients in deep learning are still under-explored. In this paper, we mainly make two contributions. First, we conduct formal statistical tests on the distribution of stochastic gradients and gradient noise across both parameters and iterations. Our statistical tests reveal that dimension-wise gradients usually exhibit power-law heavy tails, while iteration-wise gradients and stochastic gradient noise caused by minibatch training usually do not exhibit power-law heavy tails. Second, we further discover that the covariance spectra of stochastic gradients have the power-law structures in deep learning. While previous papers believed that the anisotropic structure of stochastic gradients matters to deep learning, they did not expect the gradient covariance can have such an elegant mathematical structure. Our work challenges the existing belief and provides novel insights on the structure of stochastic gradients in deep learning.
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