Sentence summarization shortens given texts while maintaining core contents of the texts. Unsupervised approaches have been studied to summarize texts without human-written summaries. However, recent unsupervised models are extractive, which remove words from texts and thus they are less flexible than abstractive summarization. In this work, we devise an abstractive model based on reinforcement learning without ground-truth summaries. We formulate the unsupervised summarization based on the Markov decision process with rewards representing the summary quality. To further enhance the summary quality, we develop a multi-summary learning mechanism that generates multiple summaries with varying lengths for a given text, while making the summaries mutually enhance each other. Experimental results show that the proposed model substantially outperforms both abstractive and extractive models, yet frequently generating new words not contained in input texts.

顺序推荐系统通过捕获用户的兴趣漂移来显示有效的建议。有两组现有的顺序模型：以用户和项目为中心的模型。以用户为中心的模型根据每个用户的顺序消费历史记录来捕获个性化的利息漂移，但没有明确考虑用户对项目的利益是否超出培训时间，即利息可持续性。另一方面，以项目为中心的模型考虑了用户在培训时间后的一般利益是否维持，但不是个性化的。在这项工作中，我们提出了一个推荐系统，将两类模型的优势占据优势。我们提出的模型捕获了个性化的利息可持续性，表明每个用户对物品的利益是否会超出培训时间。我们首先制定一项任务，该任务需要根据用户的消费历史记录预测培训时间中每个用户将消耗哪些项目。然后，我们提出简单而有效的方案，以增强用户的稀疏消费历史记录。广泛的实验表明，所提出的模型在11个现实世界数据集上的表现优于10个基线模型。这些代码可在https://github.com/dmhyun/peris上找到。

识别异常文档，其内容与语料库中的大多数文档不同，在管理大型文本集合中发挥了重要作用。但是，由于没有关于Inlier（或目标）分布的明确信息，现有的无监督异常探测器可能会根据语料库中的异常值的密度或多样性进行不可靠的结果。为了解决这一挑战，我们介绍了一项新的任务，称为类别无类别检测，该任务旨在通过使用类别名称作为弱监管来将文档与Inlier（或目标）类别的语义相关。在实践中，该任务可以广泛适用于，它可以灵活地根据用户的兴趣指定目标类别的范围，同时仅需要目标类别名称作为最小指导。在本文中，我们介绍了一个类别超类的检测框架，它有效地根据其特定于类别的相关性得分，有效地测量每个文档的一个目标类别之一。我们的框架采用两步方法; （i）它首先通过利用在文本嵌入空间中编码的单词文件相似度，然后（ii）通过使用伪标签来计算伪标签以计算置信度来生成所有未标记的文档的伪类别标签从其目标类别预测。真实世界数据集的实验表明，我们的框架在指定不同目标类别的各种场景中的所有基线方法中实现了最佳检测性能。

随着各个领域的深度学习的巨大成功，图形神经网络（GNNS）也成为图形分类的主要方法。通过全局读出操作，只会聚合所有节点（或节点群集）表示，现有的GNN分类器获得输入图的图级表示，并使用表示来预测其类标签。但是，这种全局聚合不考虑每个节点的结构信息，这导致全局结构的信息丢失。特别地，它通过对所有节点表示来强制执行分类器的相同权重参数来限制辨别力;在实践中，他们中的每一个都有助于不同于其结构语义的目标类别。在这项工作中，我们提出了结构性语义读数（SSREAD）来总结位置级节点表示，这允许为分类模拟特定位置的权重参数，以及有效地捕获与全局结构相关的图形语义。给定输入图，SSREAD旨在通过使用其节点与结构原型之间的语义对齐来识别结构上有意义的位置，该结构原型编码每个位置的原型特征。结构原型经过优化，以最小化所有训练图的对准成本，而其他GNN参数训练以预测类标签。我们的实验结果表明，SSREAD显着提高了GNN分类器的分类性能和可解释性，同时兼容各种聚合函数，GNN架构和学习框架。

Unsupervised domain adaptation (UDA) for semantic segmentation is a promising task freeing people from heavy annotation work. However, domain discrepancies in low-level image statistics and high-level contexts compromise the segmentation performance over the target domain. A key idea to tackle this problem is to perform both image-level and feature-level adaptation jointly. Unfortunately, there is a lack of such unified approaches for UDA tasks in the existing literature. This paper proposes a novel UDA pipeline for semantic segmentation that unifies image-level and feature-level adaptation. Concretely, for image-level domain shifts, we propose a global photometric alignment module and a global texture alignment module that align images in the source and target domains in terms of image-level properties. For feature-level domain shifts, we perform global manifold alignment by projecting pixel features from both domains onto the feature manifold of the source domain; and we further regularize category centers in the source domain through a category-oriented triplet loss and perform target domain consistency regularization over augmented target domain images. Experimental results demonstrate that our pipeline significantly outperforms previous methods. In the commonly tested GTA5$\rightarrow$Cityscapes task, our proposed method using Deeplab V3+ as the backbone surpasses previous SOTA by 8%, achieving 58.2% in mIoU.

Different people speak with diverse personalized speaking styles. Although existing one-shot talking head methods have made significant progress in lip sync, natural facial expressions, and stable head motions, they still cannot generate diverse speaking styles in the final talking head videos. To tackle this problem, we propose a one-shot style-controllable talking face generation framework. In a nutshell, we aim to attain a speaking style from an arbitrary reference speaking video and then drive the one-shot portrait to speak with the reference speaking style and another piece of audio. Specifically, we first develop a style encoder to extract dynamic facial motion patterns of a style reference video and then encode them into a style code. Afterward, we introduce a style-controllable decoder to synthesize stylized facial animations from the speech content and style code. In order to integrate the reference speaking style into generated videos, we design a style-aware adaptive transformer, which enables the encoded style code to adjust the weights of the feed-forward layers accordingly. Thanks to the style-aware adaptation mechanism, the reference speaking style can be better embedded into synthesized videos during decoding. Extensive experiments demonstrate that our method is capable of generating talking head videos with diverse speaking styles from only one portrait image and an audio clip while achieving authentic visual effects. Project Page: https://github.com/FuxiVirtualHuman/styletalk.

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.

Increasing research interests focus on sequential recommender systems, aiming to model dynamic sequence representation precisely. However, the most commonly used loss function in state-of-the-art sequential recommendation models has essential limitations. To name a few, Bayesian Personalized Ranking (BPR) loss suffers the vanishing gradient problem from numerous negative sampling and predictionbiases; Binary Cross-Entropy (BCE) loss subjects to negative sampling numbers, thereby it is likely to ignore valuable negative examples and reduce the training efficiency; Cross-Entropy (CE) loss only focuses on the last timestamp of the training sequence, which causes low utilization of sequence information and results in inferior user sequence representation. To avoid these limitations, in this paper, we propose to calculate Cumulative Cross-Entropy (CCE) loss over the sequence. CCE is simple and direct, which enjoys the virtues of painless deployment, no negative sampling, and effective and efficient training. We conduct extensive experiments on five benchmark datasets to demonstrate the effectiveness and efficiency of CCE. The results show that employing CCE loss on three state-of-the-art models GRU4Rec, SASRec, and S3-Rec can reach 125.63%, 69.90%, and 33.24% average improvement of full ranking NDCG@5, respectively. Using CCE, the performance curve of the models on the test data increases rapidly with the wall clock time, and is superior to that of other loss functions in almost the whole process of model training.

Recent advances in self-supervised learning (SSL) in computer vision are primarily comparative, whose goal is to preserve invariant and discriminative semantics in latent representations by comparing siamese image views. However, the preserved high-level semantics do not contain enough local information, which is vital in medical image analysis (e.g., image-based diagnosis and tumor segmentation). To mitigate the locality problem of comparative SSL, we propose to incorporate the task of pixel restoration for explicitly encoding more pixel-level information into high-level semantics. We also address the preservation of scale information, a powerful tool in aiding image understanding but has not drawn much attention in SSL. The resulting framework can be formulated as a multi-task optimization problem on the feature pyramid. Specifically, we conduct multi-scale pixel restoration and siamese feature comparison in the pyramid. In addition, we propose non-skip U-Net to build the feature pyramid and develop sub-crop to replace multi-crop in 3D medical imaging. The proposed unified SSL framework (PCRLv2) surpasses its self-supervised counterparts on various tasks, including brain tumor segmentation (BraTS 2018), chest pathology identification (ChestX-ray, CheXpert), pulmonary nodule detection (LUNA), and abdominal organ segmentation (LiTS), sometimes outperforming them by large margins with limited annotations.

The visual dimension of cities has been a fundamental subject in urban studies, since the pioneering work of scholars such as Sitte, Lynch, Arnheim, and Jacobs. Several decades later, big data and artificial intelligence (AI) are revolutionizing how people move, sense, and interact with cities. This paper reviews the literature on the appearance and function of cities to illustrate how visual information has been used to understand them. A conceptual framework, Urban Visual Intelligence, is introduced to systematically elaborate on how new image data sources and AI techniques are reshaping the way researchers perceive and measure cities, enabling the study of the physical environment and its interactions with socioeconomic environments at various scales. The paper argues that these new approaches enable researchers to revisit the classic urban theories and themes, and potentially help cities create environments that are more in line with human behaviors and aspirations in the digital age.