In contrast to the control-theoretic methods, the lack of stability guarantee remains a significant problem for model-free reinforcement learning (RL) methods. Jointly learning a policy and a Lyapunov function has recently become a promising approach to ensuring the whole system with a stability guarantee. However, the classical Lyapunov constraints researchers introduced cannot stabilize the system during the sampling-based optimization. Therefore, we propose the Adaptive Stability Certification (ASC), making the system reach sampling-based stability. Because the ASC condition can search for the optimal policy heuristically, we design the Adaptive Lyapunov-based Actor-Critic (ALAC) algorithm based on the ASC condition. Meanwhile, our algorithm avoids the optimization problem that a variety of constraints are coupled into the objective in current approaches. When evaluated on ten robotic tasks, our method achieves lower accumulated cost and fewer stability constraint violations than previous studies.

Document-level relation extraction faces two overlooked challenges: long-tail problem and multi-label problem. Previous work focuses mainly on obtaining better contextual representations for entity pairs, hardly address the above challenges. In this paper, we analyze the co-occurrence correlation of relations, and introduce it into DocRE task for the first time. We argue that the correlations can not only transfer knowledge between data-rich relations and data-scarce ones to assist in the training of tailed relations, but also reflect semantic distance guiding the classifier to identify semantically close relations for multi-label entity pairs. Specifically, we use relation embedding as a medium, and propose two co-occurrence prediction sub-tasks from both coarse- and fine-grained perspectives to capture relation correlations. Finally, the learned correlation-aware embeddings are used to guide the extraction of relational facts. Substantial experiments on two popular DocRE datasets are conducted, and our method achieves superior results compared to baselines. Insightful analysis also demonstrates the potential of relation correlations to address the above challenges.

The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.

Existing Temporal Action Detection (TAD) methods typically take a pre-processing step in converting an input varying-length video into a fixed-length snippet representation sequence, before temporal boundary estimation and action classification. This pre-processing step would temporally downsample the video, reducing the inference resolution and hampering the detection performance in the original temporal resolution. In essence, this is due to a temporal quantization error introduced during the resolution downsampling and recovery. This could negatively impact the TAD performance, but is largely ignored by existing methods. To address this problem, in this work we introduce a novel model-agnostic post-processing method without model redesign and retraining. Specifically, we model the start and end points of action instances with a Gaussian distribution for enabling temporal boundary inference at a sub-snippet level. We further introduce an efficient Taylor-expansion based approximation, dubbed as Gaussian Approximated Post-processing (GAP). Extensive experiments demonstrate that our GAP can consistently improve a wide variety of pre-trained off-the-shelf TAD models on the challenging ActivityNet (+0.2% -0.7% in average mAP) and THUMOS (+0.2% -0.5% in average mAP) benchmarks. Such performance gains are already significant and highly comparable to those achieved by novel model designs. Also, GAP can be integrated with model training for further performance gain. Importantly, GAP enables lower temporal resolutions for more efficient inference, facilitating low-resource applications. The code will be available in https://github.com/sauradip/GAP

Few-shot (FS) and zero-shot (ZS) learning are two different approaches for scaling temporal action detection (TAD) to new classes. The former adapts a pretrained vision model to a new task represented by as few as a single video per class, whilst the latter requires no training examples by exploiting a semantic description of the new class. In this work, we introduce a new multi-modality few-shot (MMFS) TAD problem, which can be considered as a marriage of FS-TAD and ZS-TAD by leveraging few-shot support videos and new class names jointly. To tackle this problem, we further introduce a novel MUlti-modality PromPt mETa-learning (MUPPET) method. This is enabled by efficiently bridging pretrained vision and language models whilst maximally reusing already learned capacity. Concretely, we construct multi-modal prompts by mapping support videos into the textual token space of a vision-language model using a meta-learned adapter-equipped visual semantics tokenizer. To tackle large intra-class variation, we further design a query feature regulation scheme. Extensive experiments on ActivityNetv1.3 and THUMOS14 demonstrate that our MUPPET outperforms state-of-the-art alternative methods, often by a large margin. We also show that our MUPPET can be easily extended to tackle the few-shot object detection problem and again achieves the state-of-the-art performance on MS-COCO dataset. The code will be available in https://github.com/sauradip/MUPPET

尖峰神经网络（SNN）是一种具有生物学知识的模型，具有高计算能力和低功耗的优势。虽然对深SNN的培训仍然是一个空旷的问题，但它限制了深SNN的现实应用。在这里，我们提出了一个名为Spiking SiamFC ++的深SNN架构，用于对象跟踪，并通过端到端直接培训。具体而言，Alexnet网络在时间域中扩展以提取该功能，并采用替代梯度功能来实现对深SNN的直接监督培训。为了检查尖峰SiAMFC ++的性能，考虑了几种跟踪基准测试，包括OTB2013，OTB2015，Dot2015，Dot2016和UAV123。发现与原始的siAMFC ++相比，精度损失很小。与现有的基于SNN的目标跟踪器相比，例如暹罗（Siamsnn），提议的Spiking SiamFC ++的精度（连续）达到了85.24％（64.37％），远高于52.78％（44.32％）的精度（64.37％）。 。据我们所知，Spiking SiamFC ++的性能优于基于SNN的对象跟踪中现有的最新方法，该方法为目标跟踪领域中的SNN应用提供了新的路径。这项工作可能会进一步促进SNN算法和神经形态芯片的发展。

生长免费的在线3D形状集合决定了3D检索的研究。然而，已经进行了积极的辩论（i）最佳输入方式是触发检索，以及（ii）这种检索的最终用法场景。在本文中，我们为回答这些问题提供了不同的观点 - 我们研究了3D草图作为输入方式，并提倡进行检索的VR-Scenario。因此，最终的愿景是用户可以通过在VR环境中自由空气供电来自由地检索3D模型。作为新的3D VR-Sketch的首次刺入3D形状检索问题，我们做出了四个贡献。首先，我们对VR实用程序进行编码以收集3D VR-Sketches并进行检索。其次，我们从ModelNet收集了两个形状类别的第一套$ 167 $ 3D VR-SKETCHES。第三，我们提出了一种新的方法，以生成不同抽象级别类似人类的3D草图的合成数据集，以训练深层网络。最后，我们比较了常见的多视图和体积方法：我们表明，与3D形状到3D形状检索相比，基于体积点的方法在3D草图上表现出卓越的性能，并且由于稀疏和抽象的性质而显示出3D形状的检索3D VR-Sketches。我们认为，这些贡献将集体成为未来在此问题的尝试的推动者。 VR接口，代码和数据集可在https://tinyurl.com/3dsketch3dv上找到。

我们介绍了1,497个3D VR草图和具有较大形状多样性的椅子类别的3D形状对的第一个细粒数据集。我们的数据集支持草图社区的最新趋势，以细粒度的数据分析，并将其扩展到主动开发的3D域。我们争辩说最方便的草图场景，其中草图由稀疏的线条组成，并且不需要任何草图技能，事先培训或耗时的准确绘图。然后，我们首次将细粒度3D VR草图的场景研究为3D形状检索，作为一种新颖的VR素描应用程序和一个探索基础，以推动通用见解以告知未来的研究。通过实验在这个新问题上精心选择的设计因素组合，我们得出重要的结论以帮助跟进工作。我们希望我们的数据集能够启用其他新颖的应用程序，尤其是那些需要细粒角的应用程序，例如细粒度的3D形状重建。该数据集可在tinyurl.com/vrsketch3dv21上获得。

我们研究基于3D-VR-Sketch的细粒度3D形状检索的实际任务。此任务特别令人感兴趣，因为2D草图被证明是2D图像的有效查询。但是，由于域间隙，很难从2D草图中以3D形状的检索获得强劲的性能。最近的工作证明了3D VR素描在此任务上的优势。在我们的工作中，我们专注于3D VR草图中固有的不准确性造成的挑战。我们观察到，带有固定边缘值的三胞胎损失获得的检索结果，通常用于检索任务，包含许多无关的形状，通常只有一个或几个或几个具有与查询相似的结构。为了减轻此问题，我们首次在自适应边距值和形状相似性之间建立联系。特别是，我们建议使用由“拟合差距”驱动的自适应边距值的三重损失，这是在结构保护变形下的两个形状的相似性。我们还进行了一项用户研究，该研究确认这种拟合差距确实是评估形状结构相似性的合适标准。此外，我们介绍了202个VR草图的数据集，用于从内存而不是观察到的202个3D形状。代码和数据可在https://github.com/rowl1ng/structure-aware-aware-vr-sketch-shape-retrieval中找到。

最近发布的EGO4D数据集和基准测试显着缩放，并使第一人称视觉感知数据多样化。在EGO4D中，视觉查询2D本地化任务旨在从第一人称视图中的录制中检索过去出现的对象。此任务需要一个系统才能在空间和时间上定位给定对象查询的最新外观，其中查询在不同场景中被对象的单个紧密视觉作物注册。我们的研究基于情节记忆基准中引入的三阶段基线。基线通过检测和跟踪解决问题：检测所有帧中的相似对象，然后从最自信的检测结果中运行跟踪器。在VQ2D挑战中，我们确定了当前基线的两个局限性。 （1）训练配置具有冗余计算。尽管培训集有数百万个实例，但其中大多数是重复的，唯一对象的数量仅为14.6k。相同对象的重复梯度计算导致效率低下的训练； （2）背景框架上的误报率很高。这是由于培训和评估之间的分布差距。在培训期间，该模型只能看到干净，稳定和标记的框架，但是以自我为中心的视频也具有嘈杂，模糊或未标记的背景框架。为此，我们开发了一个更有效的解决方案。具体来说，我们将训练环从约15天提高到不到24小时，并且达到了0.17％的空间AP，比基线高31％。我们的解决方案在公共排行榜上获得了第一个排名。我们的代码可在https://github.com/facebookresearch/vq2d_cvpr上公开获取。