This work focuses on unsupervised representation learning in person re-identification (ReID). Recent self-supervised contrastive learning methods learn invariance by maximizing the representation similarity between two augmented views of a same image. However, traditional data augmentation may bring to the fore undesirable distortions on identity features, which is not always favorable in id-sensitive ReID tasks. In this paper, we propose to replace traditional data augmentation with a generative adversarial network (GAN) that is targeted to generate augmented views for contrastive learning. A 3D mesh guided person image generator is proposed to disentangle a person image into id-related and id-unrelated features. Deviating from previous GAN-based ReID methods that only work in id-unrelated space (pose and camera style), we conduct GAN-based augmentation on both id-unrelated and id-related features. We further propose specific contrastive losses to help our network learn invariance from id-unrelated and id-related augmentations. By jointly training the generative and the contrastive modules, our method achieves new state-of-the-art unsupervised person ReID performance on mainstream large-scale benchmarks.

当前的骨架动作表示方法学习的方法通常集中在受约束的场景上，其中在实验室环境中记录了视频和骨骼数据。在处理现实世界视频中估计的骨骼数据时，由于受试者和摄像机观点之间的差异很大，因此此类方法的性能差。为了解决这个问题，我们通过一种新颖的视图自动编码器介绍了自我监视的骨架动作表示学习。通过Leverage在不同的人类表演者之间进行运动重新定位作为借口任务，以便在2D或3D骨架序列的视觉表示之上删除潜在的动作特异性“运动”特征。这种“运动”功能对于骨架几何和相机视图是不变的，并允许通过辅助，跨视图和跨视图动作分类任务。我们进行了一项研究，重点是针对基于骨架的动作识别的转移学习，并在现实世界数据（例如Posetics）上进行自我监督的预训练。我们的结果表明，从VIA中学到的骨架表示足以提高最新动作分类精度，不仅在3D实验室数据集（例如NTU-RGB+D 60和NTU-RGB+D 120）上，而且还在在仅准确估计2D数据的现实数据集中，例如Toyota Smarthome，UAV-Human和Penn Action。

对人类流动性进行建模有助于了解人们如何访问资源并在城市中彼此进行身体接触，从而有助于各种应用，例如城市规划，流行病控制和基于位置的广告。下一个位置预测是单个人类移动性建模中的一项决定性任务，通常被视为序列建模，用Markov或基于RNN的方法解决。但是，现有模型几乎不关注单个旅行决策的逻辑和人口集体行为的可重复性。为此，我们提出了一个因果关系和空间约束的长期和短期学习者（CSLSL），以进行下一个位置预测。 CSLSL利用基于多任务学习的因果结构来明确对“ $ \ rightarrow $ wher wher wher wher whit $ \ rightarrow $ where where where”，a.k.a.”接下来，我们提出一个空间约束损失函数作为辅助任务，以确保旅行者目的地的预测和实际空间分布之间的一致性。此外，CSLSL采用了名为Long and Short-Charturer（LSC）的模块，以了解不同时间跨度的过渡规律。在三个现实世界数据集上进行的广泛实验表明，CSLSL的性能改善了基准，并确认引入因果关系和一致性约束的有效性。该实现可在https://github.com/urbanmobility/cslsl上获得。

少数拍摄识别旨在在低数据制度下识别新型类别。由于图像的稀缺性，机器不能获得足够的有效信息，并且模型的泛化能力极弱。通过使用辅助语义模式​​，基于最近的公制学习的少量学习方法已经取得了有希望的表现。但是，这些方法仅增强了支持类的表示，而查询图像没有语义模态信息以增强表示。相反，我们提出了属性形状的学习（ASL），其可以将可视化表示标准化以预测查询图像的属性。我们进一步设计了一个属性 - 视觉注意力模块（Avam），它利用属性来生成更多辨别特征。我们的方法使视觉表示能够专注于具有属性指导的重要区域。实验表明，我们的方法可以在幼崽和太阳基准上实现竞争结果。我们的代码可用于{https://github.com/chenhaoxing/asl}。

从有限的数据学习是一个具有挑战性的任务，因为数据的稀缺导致训练型模型的较差。经典的全局汇总表示可能会失去有用的本地信息。最近，许多射击学习方法通​​过使用深度描述符和学习像素级度量来解决这一挑战。但是，使用深描述符作为特征表示可能丢失图像的上下文信息。这些方法中的大多数方法独立地处理支持集中的每个类，这不能充分利用鉴别性信息和特定于特定的嵌入。在本文中，我们提出了一种名为稀疏空间变压器（SSFormers）的新型变压器的神经网络架构，可以找到任务相关的功能并抑制任务无关的功能。具体地，我们首先将每个输入图像划分为不同大小的几个图像斑块，以获得密集的局部特征。这些功能在表达本地信息时保留上下文信息。然后，提出了一种稀疏的空间变压器层以在查询图像和整个支持集之间找到空间对应关系，以选择任务相关的图像斑块并抑制任务 - 无关的图像斑块。最后，我们建议使用图像补丁匹配模块来计算密集的本地表示之间的距离，从而确定查询图像属于支持集中的哪个类别。广泛的少量学习基准测试表明，我们的方法实现了最先进的性能。

少量学习致力于在少数样品上培训模型。这些方法中的大多数基于像素级或全局级别特征表示学习模型。但是，使用全局功能可能会丢失本地信息，并且使用像素级别功能可能会丢失图像的上下文语义。此外，这些作品只能在单个级别上衡量它们之间的关系，这并不全面而有效。如果查询图像可以通过三个不同的水平相似度量同时分类很好，则类内的查询图像可以在较小的特征空间中更紧密地分布，产生更多辨别特征映射。由此激励，我们提出了一种新的零件级别嵌入适应图形（PEAG）方法来生成特定于任务特征。此外，提出了一种多级度量学习（MML）方法，其不仅可以计算像素级相似度，而且还考虑了部分级别特征和全局级别特征的相似性。对流行的少量图像识别数据集进行了广泛的实验，证明了与最先进的方法相比的方法的有效性。我们的代码可用于\ url {https:/github.com/chenhaoxing/m2l}。

优化平均精度（AP）的近似已被广泛研究图像检索。受AP的定义有限，这些方法考虑在每个阳性实例之前的负数和正面情况。但是，我们声称只在积极的情况下惩罚负面情况，因为损失只来自这些负面情况。为此，我们提出了一种新的损失，即惩罚正面（PNP）的负面情况，这可以直接最小化每个正面前的负实例的数量。此外，基于AP的方法采用固定和次优梯度分配策略。因此，我们通过构建损耗的衍生功能来系统地调查不同的梯度分配解决方案，导致PNP-I具有增加的衍生函数和PNP-D，其具有减小的函数。 PNP-I通过为它们分配更大的渐变并尝试使所有相关实例更近的较大渐变来重点缩影。相比之下，PNP-D对此类实例的关注不那么注意，并慢慢纠正它们。对于大多数真实世界的数据，一类通常包含几个本地群集。 PNP-我盲目地聚集了这些群集，而PNP-D保持它们。因此，PNP-D更优越。三个标准检索数据集的实验显示了上述分析的一致结果。广泛的评估表明PNP-D实现了最先进的性能。代码在https://github.com/interestingzhuo/pnp_loss获得

In this paper, we propose a robust 3D detector, named Cross Modal Transformer (CMT), for end-to-end 3D multi-modal detection. Without explicit view transformation, CMT takes the image and point clouds tokens as inputs and directly outputs accurate 3D bounding boxes. The spatial alignment of multi-modal tokens is performed implicitly, by encoding the 3D points into multi-modal features. The core design of CMT is quite simple while its performance is impressive. CMT obtains 73.0% NDS on nuScenes benchmark. Moreover, CMT has a strong robustness even if the LiDAR is missing. Code will be released at https://github.com/junjie18/CMT.

Knowledge graphs (KG) have served as the key component of various natural language processing applications. Commonsense knowledge graphs (CKG) are a special type of KG, where entities and relations are composed of free-form text. However, previous works in KG completion and CKG completion suffer from long-tail relations and newly-added relations which do not have many know triples for training. In light of this, few-shot KG completion (FKGC), which requires the strengths of graph representation learning and few-shot learning, has been proposed to challenge the problem of limited annotated data. In this paper, we comprehensively survey previous attempts on such tasks in the form of a series of methods and applications. Specifically, we first introduce FKGC challenges, commonly used KGs, and CKGs. Then we systematically categorize and summarize existing works in terms of the type of KGs and the methods. Finally, we present applications of FKGC models on prediction tasks in different areas and share our thoughts on future research directions of FKGC.

Few Shot Instance Segmentation (FSIS) requires models to detect and segment novel classes with limited several support examples. In this work, we explore a simple yet unified solution for FSIS as well as its incremental variants, and introduce a new framework named Reference Twice (RefT) to fully explore the relationship between support/query features based on a Transformer-like framework. Our key insights are two folds: Firstly, with the aid of support masks, we can generate dynamic class centers more appropriately to re-weight query features. Secondly, we find that support object queries have already encoded key factors after base training. In this way, the query features can be enhanced twice from two aspects, i.e., feature-level and instance-level. In particular, we firstly design a mask-based dynamic weighting module to enhance support features and then propose to link object queries for better calibration via cross-attention. After the above steps, the novel classes can be improved significantly over our strong baseline. Additionally, our new framework can be easily extended to incremental FSIS with minor modification. When benchmarking results on the COCO dataset for FSIS, gFSIS, and iFSIS settings, our method achieves a competitive performance compared to existing approaches across different shots, e.g., we boost nAP by noticeable +8.2/+9.4 over the current state-of-the-art FSIS method for 10/30-shot. We further demonstrate the superiority of our approach on Few Shot Object Detection. Code and model will be available.