这项工作介绍了一个简单的视觉变压器设计，作为对象本地化和实例分段任务的强大基线。变压器最近在图像分类任务中展示了竞争性能。为了采用对象检测和密集的预测任务，许多作品从卷积网络和高度定制的Vit架构继承了多级设计。在这种设计背后，目标是在计算成本和多尺度全球背景的有效聚合之间进行更好的权衡。然而，现有的作品采用多级架构设计作为黑匣子解决方案，无清楚地了解其真正的益处。在本文中，我们全面研究了三个架构设计选择对vit - 空间减少，加倍的频道和多尺度特征 - 并证明了vanilla vit架构可以在没有手动的多尺度特征的情况下实现这一目标，保持原始的Vit设计哲学。我们进一步完成了缩放规则，以优化模型的准确性和计算成本/型号大小的权衡。通过在整个编码器块中利用恒定的特征分辨率和隐藏大小，我们提出了一种称为通用视觉变压器（UVIT）的简单而紧凑的VIT架构，可实现COCO对象检测和实例分段任务的强劲性能。

高级驾驶员辅助系统（ADA）旨在提高车辆安全性。但是，如果不了解当前ADA及其可能的解决方案的原因和局限性，就很难获得此类收益。这项研究1）通过文献综述研究了ADA的局限性和解决方案，2）通过使用自然语言处理模型来确定ADA通过消费者投诉的原因和影响，3）比较了两者之间的主要差异。这两条研究线确定了类似的ADA原因类别，包括人为因素，环境因素和车辆因素。但是，学术研究更多地集中在ADA问题的人为因素上，并提出了高级算法来减轻此类问题，而驾驶员抱怨ADAS失败的更多车辆因素，这导致了最大的后果。这两个来源的发现倾向于相互补充，并为未来的改善ADA提供了重要意义。

由于行人涉及的撞车事故的数量增加，行人安全已成为各种研究的重要研究主题。为了主动评估行人安全，替代安全措施（SSM）已被广泛用于基于交通冲突的研究中，因为它们不需要历史崩溃作为输入。但是，大多数现有的SSM是根据道路使用者保持恒定速度和方向的假设而开发的。基于此假设的风险估计较不稳定，更可能被夸大，并且无法捕获驾驶员的回避操作。考虑到现有SSM之间的局限性，本研究提出了一个概率框架，用于估计十字路口处行人车的风险。提出的框架通过使用高斯过程回归预测轨迹，并通过随机森林模型来解释不同可能的驱动器操纵，从而放大了恒定速度的限制。在十字路口收集的现实世界激光雷达数据用于评估所提出的框架的性能。新开发的框架能够识别所有行人车的冲突。与收集时间相比，提议的框架提供了更稳定的风险估计，并捕获了汽车的回避操作。此外，提议的框架不需要昂贵的计算资源，这使其成为交叉点实时主动行人安全解决方案的理想选择。

联邦学习（FL）是一个新兴机器学习范式，数据所有者可以在不共享其原始数据的情况下协作培训模型。 FL中的两个基本研究问题是激励机制和隐私保护。前者侧重于如何激励数据所有者参加FL。后者研究如何保护数据所有者的隐私，同时保持训练型模型的高效用。但是，FL中的激励机制和隐私保护已被分开研究，并且没有工作同时解决这两个问题。在这项工作中，我们通过提供适当的付款和隐私保护来解决飞行市场的两个问题，这会激励数据所有者的参与。 FL-Market使数据所有者能够根据本地差异隐私（LDP）量化的隐私损失来获得赔偿。我们的识别是，通过满足数据所有者的个性化隐私偏好并提供适当的付款，我们可以（1）激励隐私风险数据所有者设置更大的隐私参数（即，具有较少噪声的渐变）和（2）提供首选隐私保护对于隐私风险厌恶数据所有者。为实现这一目标，我们设计了一个基于LDP的FL框架，具有深度学习的拍卖机制，可以使用较少的噪音和最佳聚合机制激励交易私人模型，并将本地梯度聚合成准确的全局梯度。我们的实验验证了拟议的框架和机制的有效性。

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.

Witnessing the impressive achievements of pre-training techniques on large-scale data in the field of computer vision and natural language processing, we wonder whether this idea could be adapted in a grab-and-go spirit, and mitigate the sample inefficiency problem for visuomotor driving. Given the highly dynamic and variant nature of the input, the visuomotor driving task inherently lacks view and translation invariance, and the visual input contains massive irrelevant information for decision making, resulting in predominant pre-training approaches from general vision less suitable for the autonomous driving task. To this end, we propose PPGeo (Policy Pre-training via Geometric modeling), an intuitive and straightforward fully self-supervised framework curated for the policy pretraining in visuomotor driving. We aim at learning policy representations as a powerful abstraction by modeling 3D geometric scenes on large-scale unlabeled and uncalibrated YouTube driving videos. The proposed PPGeo is performed in two stages to support effective self-supervised training. In the first stage, the geometric modeling framework generates pose and depth predictions simultaneously, with two consecutive frames as input. In the second stage, the visual encoder learns driving policy representation by predicting the future ego-motion and optimizing with the photometric error based on current visual observation only. As such, the pre-trained visual encoder is equipped with rich driving policy related representations and thereby competent for multiple visuomotor driving tasks. Extensive experiments covering a wide span of challenging scenarios have demonstrated the superiority of our proposed approach, where improvements range from 2% to even over 100% with very limited data. Code and models will be available at https://github.com/OpenDriveLab/PPGeo.