在交互环境中学习操纵3D对象一直是强化学习（RL）的挑战性问题。特别是，很难训练可以概括具有不同语义类别，多样形状几何形状和多功能功能的对象的策略。最近，视觉负担能力的技术在提供有效的可操作语义方面提供了以对象为中心的信息先验的前景。因此，可以通过知道如何在手柄上施加力来训练有效的政策来打开门。但是，要学习负担能力，它通常需要人为定义的动作基础，这限制了适用的任务范围。在这项研究中，我们通过使用RL训练过程中生成的联系信息来预测感兴趣的接触图，利用视觉负担。然后，这种联系预测过程会导致一个端到端的负担能力学习框架，该框架可以概括不同类型的操纵任务。令人惊讶的是，这种框架的有效性即使在多阶段和多代理场景下也具有。我们对八种类型的操纵任务进行了测试。结果表明，我们的方法优于基线算法，包括基于视觉的负担方法和RL方法，其成功率很大。演示可以在https://sites.google.com/view/rlafford/上找到。

实现人类水平的灵活性是机器人技术中的重要开放问题。但是，即使在婴儿级别，灵巧的手动操纵任务也是通过增强学习（RL）的挑战。困难在于高度的自由度和异质因素（例如手指关节）之间所需的合作。在这项研究中，我们提出了双人灵感手基准（BI-DEXHANDS），这是一种模拟器，涉及两只灵巧的手，其中包含数十只双人操纵任务和数千个目标对象。具体而言，根据认知科学文献，BI-DEXHANDS中的任务旨在匹配不同级别的人类运动技能。我们在ISSAC体育馆里建造了Bi-Dexhands；这可以实现高效的RL培训，仅在一个NVIDIA RTX 3090中达到30,000+ fps。我们在不同的设置下为流行的RL算法提供了全面的基准；这包括单代理/多代理RL，离线RL，多任务RL和META RL。我们的结果表明，PPO类型的上车算法可以掌握简单的操纵任务，该任务等效到48个月的人类婴儿（例如，捕获飞行的物体，打开瓶子），而多代理RL可以进一步帮助掌握掌握需要熟练的双人合作的操作（例如，举起锅，堆叠块）。尽管每个任务都取得了成功，但在获得多个操纵技能方面，现有的RL算法无法在大多数多任务和少量学习设置中工作，这需要从RL社区进行更实质性的发展。我们的项目通过https://github.com/pku-marl/dexteroushands开放。

In medical image segmentation, it is often necessary to collect opinions from multiple experts to make the final decision. This clinical routine helps to mitigate individual bias. But when data is multiply annotated, standard deep learning models are often not applicable. In this paper, we propose a novel neural network framework, called Multi-Rater Prism (MrPrism) to learn the medical image segmentation from multiple labels. Inspired by the iterative half-quadratic optimization, the proposed MrPrism will combine the multi-rater confidences assignment task and calibrated segmentation task in a recurrent manner. In this recurrent process, MrPrism can learn inter-observer variability taking into account the image semantic properties, and finally converges to a self-calibrated segmentation result reflecting the inter-observer agreement. Specifically, we propose Converging Prism (ConP) and Diverging Prism (DivP) to process the two tasks iteratively. ConP learns calibrated segmentation based on the multi-rater confidence maps estimated by DivP. DivP generates multi-rater confidence maps based on the segmentation masks estimated by ConP. The experimental results show that by recurrently running ConP and DivP, the two tasks can achieve mutual improvement. The final converged segmentation result of MrPrism outperforms state-of-the-art (SOTA) strategies on a wide range of medical image segmentation tasks.

开放式杂货店是一家杂货店，客户不必排队等待。开发这样的系统并不是微不足道的，因为它面临着认识到人的动态和巨大流动的挑战。特别是，可以有效地将每个快照分配给相应客户的聚类方法对于系统至关重要。为了解决无公开结帐杂货店中的独特挑战，我们提出了一种有效的人群聚类方法。具体而言，我们首先提出一个拥挤的子图（CSG），以将大规模和连续数据流之间的关系定位。 CSG由拟议的选择链接 - 重量（plw）策略构建，\ textbf {picks}基于时间空间信息的节点，\ textbf {links}通过轨迹信息和\ textbf {comute} links}链接由拟议的von mises-fisher（VMF）相似性度量。然后，为了确保该方法适应动态和看不见的人的流程，我们提出了图形卷积网络（GCN），采用简单的最近邻居（NN）策略，以准确地聚集CSG的实例。 GCN被采用以将功能投射到低维可分离空间中，而NN能够快速在动态人流动下为此空间产生结果。实验结果表明，在这种情况下，提出的方法优于其他替代算法。实际上，整个系统已被实施并部署在几个现实的开放式杂货中。

In recent years, Siamese network based trackers have significantly advanced the state-of-the-art in real-time tracking. Despite their success, Siamese trackers tend to suffer from high memory costs, which restrict their applicability to mobile devices with tight memory budgets. To address this issue, we propose a distilled Siamese tracking framework to learn small, fast and accurate trackers (students), which capture critical knowledge from large Siamese trackers (teachers) by a teacher-students knowledge distillation model. This model is intuitively inspired by the one teacher vs. multiple students learning method typically employed in schools. In particular, our model contains a single teacher-student distillation module and a student-student knowledge sharing mechanism. The former is designed using a tracking-specific distillation strategy to transfer knowledge from a teacher to students. The latter is utilized for mutual learning between students to enable in-depth knowledge understanding. Extensive empirical evaluations on several popular Siamese trackers demonstrate the generality and effectiveness of our framework. Moreover, the results on five tracking benchmarks show that the proposed distilled trackers achieve compression rates of up to 18$\times$ and frame-rates of $265$ FPS, while obtaining comparable tracking accuracy compared to base models.

Deep learning models can achieve high accuracy when trained on large amounts of labeled data. However, real-world scenarios often involve several challenges: Training data may become available in installments, may originate from multiple different domains, and may not contain labels for training. Certain settings, for instance medical applications, often involve further restrictions that prohibit retention of previously seen data due to privacy regulations. In this work, to address such challenges, we study unsupervised segmentation in continual learning scenarios that involve domain shift. To that end, we introduce GarDA (Generative Appearance Replay for continual Domain Adaptation), a generative-replay based approach that can adapt a segmentation model sequentially to new domains with unlabeled data. In contrast to single-step unsupervised domain adaptation (UDA), continual adaptation to a sequence of domains enables leveraging and consolidation of information from multiple domains. Unlike previous approaches in incremental UDA, our method does not require access to previously seen data, making it applicable in many practical scenarios. We evaluate GarDA on two datasets with different organs and modalities, where it substantially outperforms existing techniques.

The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.

As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.

Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.

We propose a distributionally robust return-risk model for Markov decision processes (MDPs) under risk and reward ambiguity. The proposed model optimizes the weighted average of mean and percentile performances, and it covers the distributionally robust MDPs and the distributionally robust chance-constrained MDPs (both under reward ambiguity) as special cases. By considering that the unknown reward distribution lies in a Wasserstein ambiguity set, we derive the tractable reformulation for our model. In particular, we show that that the return-risk model can also account for risk from uncertain transition kernel when one only seeks deterministic policies, and that a distributionally robust MDP under the percentile criterion can be reformulated as its nominal counterpart at an adjusted risk level. A scalable first-order algorithm is designed to solve large-scale problems, and we demonstrate the advantages of our proposed model and algorithm through numerical experiments.