这项工作是在培训生成动作/视频识别模型上，其输出是描述视频的自由形式的特定动作标题（而不是动作类标签）。生成的方法具有实用的优势，例如生产更细粒度和人类可读的产出，并且自然而然地是开放的。为此，我们提议适应视频/动作识别的预先训练的生成视觉和语言（V＆L）基础模型。据我们所知，最近有几次尝试适应了用对比度学习（例如剪辑）训练的V＆L模型（例如剪辑），但据我们所知，我们提出了第一种设定实现这一目标的方法来实现生成模型的方法。我们首先表明，生成模型的直接微调生产具有严重过度拟合的动作类别。为了减轻这一点，我们介绍了REST，这是一个由两个关键组成部分组成的培训框架：一种无监督的方法，用于通过伪捕获生成和自我训练，将生成模型适应动作/视频，即不使用任何动作特定的标签； （b）基于剪辑的检索方法，用于为每个视频发现一套伪装的伪扣，以训练该模型。重要的是，我们表明这两个组件对于获得高精度都是必要的。我们评估零拍动识别的问题的休息，我们表明，与基于对比的学习方法相比，我们的方法非常有竞争力。代码将可用。

基于Heatmap回归的深度学习模型彻底改变了面部地标定位的任务，现有模型在大型姿势，非均匀照明和阴影，闭塞和自闭合，低分辨率和模糊。然而，尽管采用了广泛的采用，Heatmap回归方法遭受与热图编码和解码过程相关的离散化引起的误差。在这项工作中，我们表明这些误差对面部对准精度具有令人惊讶的大量负面影响。为了减轻这个问题，我们通过利用底层连续分布提出了一种热爱编码和解码过程的新方法。为了充分利用新提出的编码解码机制，我们还介绍了基于暹罗的训练，该训练能够在各种几何图像变换上实施热线图一致性。我们的方法在多个数据集中提供了明显的增益，在面部地标本地化中设置新的最先进的结果。旁边的代码将在https://www.adrianbulat.com/face-alignment上提供

学习普遍面孔表示的最佳方法是什么？在面部分析领域进行深度学习的最新工作集中在监督方面的学习特定任务（例如面部识别，面部地标本地化等），但忽略了如何找到可以轻松适应面部表征的总体问题到几个面部分析任务和数据集。为此，我们做出以下4个贡献：（a）我们首次介绍面部表示学习的全面评估基准，该基准由5个重要​​的面部分析任务组成。 （b）我们系统地研究了应用于面孔的大规模表示学习的两种方式：受监督和无监督的预训练。重要的是，我们将评估重点放在几乎没有面部学习的情况下。 （c）我们研究了培训数据集的重要特性，包括其大小和质量（标记，未标记甚至未经保育）。 （d）为了得出结论，我们进行了大量实验。我们的主要两个发现是：（1）完全在野外的未经监督的预培训，未经保育的数据提供了一致的，在某些情况下，对所有面部任务进行了显着准确的改进。 （2）许多现有的面部视频数据集似乎具有大量冗余。我们将发布代码和预先培训的模型，以促进未来的研究。

In this work, we address the problem of unsupervised moving object segmentation (MOS) in 4D LiDAR data recorded from a stationary sensor, where no ground truth annotations are involved. Deep learning-based state-of-the-art methods for LiDAR MOS strongly depend on annotated ground truth data, which is expensive to obtain and scarce in existence. To close this gap in the stationary setting, we propose a novel 4D LiDAR representation based on multivariate time series that relaxes the problem of unsupervised MOS to a time series clustering problem. More specifically, we propose modeling the change in occupancy of a voxel by a multivariate occupancy time series (MOTS), which captures spatio-temporal occupancy changes on the voxel level and its surrounding neighborhood. To perform unsupervised MOS, we train a neural network in a self-supervised manner to encode MOTS into voxel-level feature representations, which can be partitioned by a clustering algorithm into moving or stationary. Experiments on stationary scenes from the Raw KITTI dataset show that our fully unsupervised approach achieves performance that is comparable to that of supervised state-of-the-art approaches.

Many prior language modeling efforts have shown that pre-training on an in-domain corpus can significantly improve performance on downstream domain-specific NLP tasks. However, the difficulties associated with collecting enough in-domain data might discourage researchers from approaching this pre-training task. In this paper, we conducted a series of experiments by pre-training Bidirectional Encoder Representations from Transformers (BERT) with different sizes of biomedical corpora. The results demonstrate that pre-training on a relatively small amount of in-domain data (4GB) with limited training steps, can lead to better performance on downstream domain-specific NLP tasks compared with fine-tuning models pre-trained on general corpora.

In this paper, we explore the relationship between an individual's writing style and the risk that they will engage in online harmful behaviors (such as cyberbullying). In particular, we consider whether measurable differences in writing style relate to different personality types, as modeled by the Big-Five personality traits and the Dark Triad traits, and can differentiate between users who do or do not engage in harmful behaviors. We study messages from nearly 2,500 users from two online communities (Twitter and Reddit) and find that we can measure significant personality differences between regular and harmful users from the writing style of as few as 100 tweets or 40 Reddit posts, aggregate these values to distinguish between healthy and harmful communities, and also use style attributes to predict which users will engage in harmful behaviors.

In this paper, we propose an end-to-end framework that jointly learns keypoint detection, descriptor representation and cross-frame matching for the task of image-based 3D localization. Prior art has tackled each of these components individually, purportedly aiming to alleviate difficulties in effectively train a holistic network. We design a self-supervised image warping correspondence loss for both feature detection and matching, a weakly-supervised epipolar constraints loss on relative camera pose learning, and a directional matching scheme that detects key-point features in a source image and performs coarse-to-fine correspondence search on the target image. We leverage this framework to enforce cycle consistency in our matching module. In addition, we propose a new loss to robustly handle both definite inlier/outlier matches and less-certain matches. The integration of these learning mechanisms enables end-to-end training of a single network performing all three localization components. Bench-marking our approach on public data-sets, exemplifies how such an end-to-end framework is able to yield more accurate localization that out-performs both traditional methods as well as state-of-the-art weakly supervised methods.

3D autonomous driving semantic segmentation using deep learning has become, a well-studied subject, providing methods that can reach very high performance. Nonetheless, because of the limited size of the training datasets, these models cannot see every type of object and scenes found in real-world applications. The ability to be reliable in these various unknown environments is called domain generalization. Despite its importance, domain generalization is relatively unexplored in the case of 3D autonomous driving semantic segmentation. To fill this gap, this paper presents the first benchmark for this application by testing state-of-the-art methods and discussing the difficulty of tackling LiDAR domain shifts. We also propose the first method designed to address this domain generalization, which we call 3DLabelProp. This method relies on leveraging the geometry and sequentiality of the LiDAR data to enhance its generalization performances by working on partially accumulated point clouds. It reaches a mIoU of 52.6% on SemanticPOSS while being trained only on SemanticKITTI, making it state-of-the-art method for generalization (+7.4% better than the second best method). The code for this method will be available on Github.

Quantitative cancer image analysis relies on the accurate delineation of tumours, a very specialised and time-consuming task. For this reason, methods for automated segmentation of tumours in medical imaging have been extensively developed in recent years, being Computed Tomography one of the most popular imaging modalities explored. However, the large amount of 3D voxels in a typical scan is prohibitive for the entire volume to be analysed at once in conventional hardware. To overcome this issue, the processes of downsampling and/or resampling are generally implemented when using traditional convolutional neural networks in medical imaging. In this paper, we propose a new methodology that introduces a process of sparsification of the input images and submanifold sparse convolutional networks as an alternative to downsampling. As a proof of concept, we applied this new methodology to Computed Tomography images of renal cancer patients, obtaining performances of segmentations of kidneys and tumours competitive with previous methods (~84.6% Dice similarity coefficient), while achieving a significant improvement in computation time (2-3 min per training epoch).

In constrained reinforcement learning (C-RL), an agent seeks to learn from the environment a policy that maximizes the expected cumulative reward while satisfying minimum requirements in secondary cumulative reward constraints. Several algorithms rooted in sampled-based primal-dual methods have been recently proposed to solve this problem in policy space. However, such methods are based on stochastic gradient descent ascent algorithms whose trajectories are connected to the optimal policy only after a mixing output stage that depends on the algorithm's history. As a result, there is a mismatch between the behavioral policy and the optimal one. In this work, we propose a novel algorithm for constrained RL that does not suffer from these limitations. Leveraging recent results on regularized saddle-flow dynamics, we develop a novel stochastic gradient descent-ascent algorithm whose trajectories converge to the optimal policy almost surely.