粗粒（CG）分子模拟已成为研究全原子模拟无法访问的时间和长度尺度上分子过程的标准工具。参数化CG力场以匹配全原子模拟，主要依赖于力匹配或相对熵最小化，这些熵最小化分别需要来自具有全原子或CG分辨率的昂贵模拟中的许多样本。在这里，我们提出了流量匹配，这是一种针对CG力场的新训练方法，它通过利用正常流量（一种生成的深度学习方法）来结合两种方法的优势。流量匹配首先训练标准化流程以表示CG概率密度，这等同于最小化相对熵而无需迭代CG模拟。随后，该流量根据学习分布生成样品和力，以通过力匹配来训练所需的CG能量模型。即使不需要全部原子模拟的力，流程匹配就数据效率的数量级优于经典力匹配，并产生CG模型，可以捕获小蛋白质的折叠和展开过渡。

在本文中，我们提出了一种真正的群体级对比度视觉表示学习方法，其在Imagenet上的线性评估表现超过了香草的监督学习。两个主流的无监督学习方案是实例级对比框架和基于聚类的方案。前者采用了极为细粒度的实例级别歧视，由于虚假负面因素，其监督信号无法有效。尽管后者解决了这一点，但它们通常会受到影响性能的一些限制。为了整合他们的优势，我们设计了烟雾方法。烟雾遵循对比度学习的框架，但取代了对比度单元，从而模仿了基于聚类的方法。为了实现这一目标，我们提出了同步执行特征分组与表示学习的动量分组方案。通过这种方式，烟雾解决了基于聚类的方法通常面对的监督信号滞后问题，并减少了实例对比方法的错误负面因素。我们进行详尽的实验，以表明烟雾在CNN和变压器骨架上都很好地工作。结果证明，烟雾已经超过了当前的SOTA无监督的表示方法。此外，其线性评估结果超过了通过香草监督学习获得的性能，并且可以很好地转移到下游任务。

利用TRIMAP引导和融合多级功能是具有像素级预测的基于Trimap的垫子的两个重要问题。为了利用Trimap指导，大多数现有方法只需将TRIMAPS和图像连接在一起，以馈送深网络或应用额外的网络以提取更多的TRIMAP指导，这符合效率和效率之间的冲突。对于新兴的基于内容的特征融合，大多数现有的消光方法仅关注本地特征，这些功能缺乏与有趣对象相关的强大语义信息的全局功能的指导。在本文中，我们提出了一种由我们的Trimap引导的非背景多尺度池（TMP）模块和全球本地背景信息融合（GLF）模块组成的Trimap-Goided Feats挖掘和融合网络。考虑到Trimap提供强大的语义指导，我们的TMP模块在Trimap的指导下对有趣的对象进行了有效的特征挖掘，而无需额外参数。此外，我们的GLF模块使用我们的TMP模块开采的有趣物体的全局语义信息，以指导有效的全局本地上下文感知多级功能融合。此外，我们建立了一个共同的有趣的物体消光（CIOM）数据集，以推进高质量的图像消光。在组合物-1K测试集，Alphamatting基准和我们的CIOM测试集上的实验结果表明，我们的方法优于最先进的方法。代码和模型将很快公开发布。

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.

As one of the most important psychic stress reactions, micro-expressions (MEs), are spontaneous and transient facial expressions that can reveal the genuine emotions of human beings. Thus, recognizing MEs (MER) automatically is becoming increasingly crucial in the field of affective computing, and provides essential technical support in lie detection, psychological analysis and other areas. However, the lack of abundant ME data seriously restricts the development of cutting-edge data-driven MER models. Despite the recent efforts of several spontaneous ME datasets to alleviate this problem, it is still a tiny amount of work. To solve the problem of ME data hunger, we construct a dynamic spontaneous ME dataset with the largest current ME data scale, called DFME (Dynamic Facial Micro-expressions), which includes 7,526 well-labeled ME videos induced by 671 participants and annotated by more than 20 annotators throughout three years. Afterwards, we adopt four classical spatiotemporal feature learning models on DFME to perform MER experiments to objectively verify the validity of DFME dataset. In addition, we explore different solutions to the class imbalance and key-frame sequence sampling problems in dynamic MER respectively on DFME, so as to provide a valuable reference for future research. The comprehensive experimental results show that our DFME dataset can facilitate the research of automatic MER, and provide a new benchmark for MER. DFME will be published via https://mea-lab-421.github.io.