我们提供了与随机敏感和非敏感背景公平在线学习的环境和一般方法。该设置是播放器和性质之间的重复游戏,在每个阶段都在每个阶段都根据上下文选择动作。灵感来自不知意的概念,我们假设玩家只能在做出决定之前访问非敏感上下文,而我们讨论两种自然案例访问敏感上下文和性质不知道敏感的背景。适应Blackwell的可平衡性理论来处理未知背景分配的情况,我们为学习目标提供了一般的必要和充分条件,以与一些公平的限制兼容。将这种条件实例化(Group-Wise)无遗憾和(Group-Wise)校准目标,以及作为额外约束的人口统计奇偶校验。当目标与约束不兼容时,所提供的框架允许在两者之间表征最佳权衡。
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我们考虑使用$ K $臂的随机匪徒问题,每一个都与$ [m,m] $范围内支持的有限分布相关。我们不认为$ [m,m] $是已知的范围,并表明学习此范围有成本。确实,出现了与分销相关和无分配后悔界限之间的新权衡,这阻止了同时实现典型的$ \ ln t $和$ \ sqrt {t} $ bunds。例如,仅当与分布相关的遗憾界限至少属于$ \ sqrt {t} $的顺序时,才能实现$ \ sqrt {t} $}无分布遗憾。我们展示了一项策略,以实现新的权衡表明的遗憾。
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我们考虑$ k $武装的随机土匪,并考虑到$ t $ t $的累积后悔界限。我们对同时获得最佳订单$ \ sqrt {kt} $的策略感兴趣,并与发行依赖的遗憾相关,即与$ \ kappa \ ln t $相匹配,该遗憾是最佳的。和Robbins(1985)以及Burnetas和Katehakis(1996),其中$ \ kappa $是最佳问题依赖性常数。这个常数的$ \ kappa $取决于所考虑的模型$ \ Mathcal {d} $(武器上可能的分布家族)。 M \'Enard and Garivier(2017)提供了在一维指数式家庭给出的模型的参数案例中实现这种双重偏见的策略,而Lattimore(2016,2018)为(Sub)高斯分布的家族而做到了这一点。差异小于$ 1 $。我们将此结果扩展到超过$ [0,1] $的所有分布的非参数案例。我们通过结合Audibert和Bubeck(2009)的MOSS策略来做到这一点,该策略享受了最佳订单$ \ sqrt {kt} $的无分配遗憾,以及Capp \'e等人的KL-UCB策略。 (2013年),我们为此提供了对最佳分布$ \ kappa \ ln t $遗憾的首次分析。我们能够在努力简化证明(以前已知的遗憾界限,因此进行的新分析)时,能够获得这种非参数两次审查结果;因此,本贡献的第二个优点是为基于$ k $武装的随机土匪提供基于索引的策略的经典后悔界限的证明。
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View-dependent effects such as reflections pose a substantial challenge for image-based and neural rendering algorithms. Above all, curved reflectors are particularly hard, as they lead to highly non-linear reflection flows as the camera moves. We introduce a new point-based representation to compute Neural Point Catacaustics allowing novel-view synthesis of scenes with curved reflectors, from a set of casually-captured input photos. At the core of our method is a neural warp field that models catacaustic trajectories of reflections, so complex specular effects can be rendered using efficient point splatting in conjunction with a neural renderer. One of our key contributions is the explicit representation of reflections with a reflection point cloud which is displaced by the neural warp field, and a primary point cloud which is optimized to represent the rest of the scene. After a short manual annotation step, our approach allows interactive high-quality renderings of novel views with accurate reflection flow. Additionally, the explicit representation of reflection flow supports several forms of scene manipulation in captured scenes, such as reflection editing, cloning of specular objects, reflection tracking across views, and comfortable stereo viewing. We provide the source code and other supplemental material on https://repo-sam.inria.fr/ fungraph/neural_catacaustics/
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Analogical proportions compare pairs of items (a, b) and (c, d) in terms of their differences and similarities. They play a key role in the formalization of analogical inference. The paper first discusses how to improve analogical inference in terms of accuracy and in terms of computational cost. Then it indicates the potential of analogical proportions for explanation. Finally, it highlights the close relationship between analogical proportions and multi-valued dependencies, which reveals an unsuspected aspect of the former.
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Recent advances in self-supervised visual representation learning have paved the way for unsupervised methods tackling tasks such as object discovery and instance segmentation. However, discovering objects in an image with no supervision is a very hard task; what are the desired objects, when to separate them into parts, how many are there, and of what classes? The answers to these questions depend on the tasks and datasets of evaluation. In this work, we take a different approach and propose to look for the background instead. This way, the salient objects emerge as a by-product without any strong assumption on what an object should be. We propose FOUND, a simple model made of a single $conv1\times1$ initialized with coarse background masks extracted from self-supervised patch-based representations. After fast training and refining these seed masks, the model reaches state-of-the-art results on unsupervised saliency detection and object discovery benchmarks. Moreover, we show that our approach yields good results in the unsupervised semantic segmentation retrieval task. The code to reproduce our results is available at https://github.com/valeoai/FOUND.
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We propose a new self-supervised method for pre-training the backbone of deep perception models operating on point clouds. The core idea is to train the model on a pretext task which is the reconstruction of the surface on which the 3D points are sampled, and to use the underlying latent vectors as input to the perception head. The intuition is that if the network is able to reconstruct the scene surface, given only sparse input points, then it probably also captures some fragments of semantic information, that can be used to boost an actual perception task. This principle has a very simple formulation, which makes it both easy to implement and widely applicable to a large range of 3D sensors and deep networks performing semantic segmentation or object detection. In fact, it supports a single-stream pipeline, as opposed to most contrastive learning approaches, allowing training on limited resources. We conducted extensive experiments on various autonomous driving datasets, involving very different kinds of lidars, for both semantic segmentation and object detection. The results show the effectiveness of our method to learn useful representations without any annotation, compared to existing approaches. Code is available at \href{https://github.com/valeoai/ALSO}{github.com/valeoai/ALSO}
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Deep learning has emerged as an effective solution for solving the task of object detection in images but at the cost of requiring large labeled datasets. To mitigate this cost, semi-supervised object detection methods, which consist in leveraging abundant unlabeled data, have been proposed and have already shown impressive results. However, most of these methods require linking a pseudo-label to a ground-truth object by thresholding. In previous works, this threshold value is usually determined empirically, which is time consuming, and only done for a single data distribution. When the domain, and thus the data distribution, changes, a new and costly parameter search is necessary. In this work, we introduce our method Adaptive Self-Training for Object Detection (ASTOD), which is a simple yet effective teacher-student method. ASTOD determines without cost a threshold value based directly on the ground value of the score histogram. To improve the quality of the teacher predictions, we also propose a novel pseudo-labeling procedure. We use different views of the unlabeled images during the pseudo-labeling step to reduce the number of missed predictions and thus obtain better candidate labels. Our teacher and our student are trained separately, and our method can be used in an iterative fashion by replacing the teacher by the student. On the MS-COCO dataset, our method consistently performs favorably against state-of-the-art methods that do not require a threshold parameter, and shows competitive results with methods that require a parameter sweep search. Additional experiments with respect to a supervised baseline on the DIOR dataset containing satellite images lead to similar conclusions, and prove that it is possible to adapt the score threshold automatically in self-training, regardless of the data distribution.
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A paper of Alsinglawi et al was recently accepted and published in Scientific Reports. In this paper, the authors aim to predict length of stay (LOS), discretized into either long (> 7 days) or short stays (< 7 days), of lung cancer patients in an ICU department using various machine learning techniques. The authors claim to achieve perfect results with an Area Under the Receiver Operating Characteristic curve (AUROC) of 100% with a Random Forest (RF) classifier with ADASYN class balancing over sampling technique, which if accurate could have significant implications for hospital management. However, we have identified several methodological flaws within the manuscript which cause the results to be overly optimistic and would have serious consequences if used in a clinical practice. Moreover, the reporting of the methodology is unclear and many important details are missing from the manuscript, which makes reproduction extremely difficult. We highlight the effect these oversights have had on the result and provide a more believable result of 88.91% AUROC when these oversights are corrected.
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在这项工作中,我们探讨了对物体在看不见的世界中同时本地化和映射中的使用,并提出了一个对象辅助系统(OA-Slam)。更确切地说,我们表明,与低级点相比,物体的主要好处在于它们的高级语义和歧视力。相反,要点比代表对象(Cuboid或椭圆形)的通用粗模型具有更好的空间定位精度。我们表明,将点和对象组合非常有趣,可以解决相机姿势恢复的问题。我们的主要贡献是:(1)我们使用高级对象地标提高了SLAM系统的重新定位能力; (2)我们构建了一个能够使用3D椭圆形识别,跟踪和重建对象的自动系统; (3)我们表明,基于对象的本地化可用于重新初始化或恢复相机跟踪。我们的全自动系统允许对象映射和增强姿势跟踪恢复,我们认为这可以极大地受益于AR社区。我们的实验表明,可以从经典方法失败的视点重新定位相机。我们证明,尽管跟踪损失损失,但这种本地化使SLAM系统仍可以继续工作,而这种损失可能会经常发生在不理会的用户中。我们的代码和测试数据在gitlab.inria.fr/tangram/oa-slam上发布。
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