在这项工作中,我们通过混合现实(MR)应用中的视频传球来探讨自幻想的创建。我们介绍了我们的端到端系统,包括:在商业头部安装显示器(HMD)上进行自定义MR视频通行证实现,我们基于深度学习的实时egpocentric身体细分算法以及我们优化的卸载体系结构,以交流使用HMD分割服务器。为了验证这项技术,我们设计了一种身临其境的VR体验,用户必须在活跃的火山火山口中穿过狭窄的瓷砖路径。这项研究是在三个身体表示条件下进行的:虚拟手,带有颜色的全身分割的视频传递以及深度学习全身分割的视频通行。这种身临其境的经历由30名女性和28名男性进行。据我们所知,这是首次旨在评估基于视频的自我avatar的用户研究,以代表用户在MR场景中。结果表明,不同身体表示在存在方面没有显着差异,虚拟手和全身表示之间的某些实施方案中等改善。视觉质量结果表明,就整个身体感知和整体分割质量而言,深入学习算法的结果更好。我们提供了一些关于使用基于视频的自我幻想的讨论,以及对评估方法的一些思考。提出的E2E解决方案处于最新技术状态的边界,因此在达到成熟之前仍有改进的空间。但是,该溶液是新型MR分布式溶液的关键起点。
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在这项工作中,我们介绍了我们的实时自我分割算法。由于我们在Thundernet的架构中灵感的浅网络,我们的算法对于640x480的输入分辨率达到了66 fps的帧速率。此外,我们非常重视培训数据的可变性。更具体地说,我们描述了我们的自我中心物体(Egobodies)数据集的创建过程,该数据集由来自三个数据集的近10,000张图像组成,这些图像既来自综合方法和真实捕获。我们进行实验以了解各个数据集的贡献;比较用自行车训练的Thundernet模型,并以更简单,更复杂的先前方法进行比较,并在分段质量和推理时间上以现实生活设置进行了相应的性能。所描述的经过训练的语义分割算法已经集成到混合现实的端到端系统中,使用户有可能在沉浸在MR场景中时看到自己的身体。
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In robust Markov decision processes (MDPs), the uncertainty in the transition kernel is addressed by finding a policy that optimizes the worst-case performance over an uncertainty set of MDPs. While much of the literature has focused on discounted MDPs, robust average-reward MDPs remain largely unexplored. In this paper, we focus on robust average-reward MDPs, where the goal is to find a policy that optimizes the worst-case average reward over an uncertainty set. We first take an approach that approximates average-reward MDPs using discounted MDPs. We prove that the robust discounted value function converges to the robust average-reward as the discount factor $\gamma$ goes to $1$, and moreover, when $\gamma$ is large, any optimal policy of the robust discounted MDP is also an optimal policy of the robust average-reward. We further design a robust dynamic programming approach, and theoretically characterize its convergence to the optimum. Then, we investigate robust average-reward MDPs directly without using discounted MDPs as an intermediate step. We derive the robust Bellman equation for robust average-reward MDPs, prove that the optimal policy can be derived from its solution, and further design a robust relative value iteration algorithm that provably finds its solution, or equivalently, the optimal robust policy.
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Masked Image Modelling (MIM) has been shown to be an efficient self-supervised learning (SSL) pre-training paradigm when paired with transformer architectures and in the presence of a large amount of unlabelled natural images. The combination of the difficulties in accessing and obtaining large amounts of labeled data and the availability of unlabelled data in the medical imaging domain makes MIM an interesting approach to advance deep learning (DL) applications based on 3D medical imaging data. Nevertheless, SSL and, in particular, MIM applications with medical imaging data are rather scarce and there is still uncertainty. around the potential of such a learning paradigm in the medical domain. We study MIM in the context of Prostate Cancer (PCa) lesion classification with T2 weighted (T2w) axial magnetic resonance imaging (MRI) data. In particular, we explore the effect of using MIM when coupled with convolutional neural networks (CNNs) under different conditions such as different masking strategies, obtaining better results in terms of AUC than other pre-training strategies like ImageNet weight initialization.
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We introduce a machine-learning (ML)-based weather simulator--called "GraphCast"--which outperforms the most accurate deterministic operational medium-range weather forecasting system in the world, as well as all previous ML baselines. GraphCast is an autoregressive model, based on graph neural networks and a novel high-resolution multi-scale mesh representation, which we trained on historical weather data from the European Centre for Medium-Range Weather Forecasts (ECMWF)'s ERA5 reanalysis archive. It can make 10-day forecasts, at 6-hour time intervals, of five surface variables and six atmospheric variables, each at 37 vertical pressure levels, on a 0.25-degree latitude-longitude grid, which corresponds to roughly 25 x 25 kilometer resolution at the equator. Our results show GraphCast is more accurate than ECMWF's deterministic operational forecasting system, HRES, on 90.0% of the 2760 variable and lead time combinations we evaluated. GraphCast also outperforms the most accurate previous ML-based weather forecasting model on 99.2% of the 252 targets it reported. GraphCast can generate a 10-day forecast (35 gigabytes of data) in under 60 seconds on Cloud TPU v4 hardware. Unlike traditional forecasting methods, ML-based forecasting scales well with data: by training on bigger, higher quality, and more recent data, the skill of the forecasts can improve. Together these results represent a key step forward in complementing and improving weather modeling with ML, open new opportunities for fast, accurate forecasting, and help realize the promise of ML-based simulation in the physical sciences.
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Modern machine learning pipelines are limited due to data availability, storage quotas, privacy regulations, and expensive annotation processes. These constraints make it difficult or impossible to maintain a large-scale model trained on growing annotation sets. Continual learning directly approaches this problem, with the ultimate goal of devising methods where a neural network effectively learns relevant patterns for new (unseen) classes without significantly altering its performance on previously learned ones. In this paper, we address the problem of continual learning for video data. We introduce PIVOT, a novel method that leverages the extensive knowledge in pre-trained models from the image domain, thereby reducing the number of trainable parameters and the associated forgetting. Unlike previous methods, ours is the first approach that effectively uses prompting mechanisms for continual learning without any in-domain pre-training. Our experiments show that PIVOT improves state-of-the-art methods by a significant 27% on the 20-task ActivityNet setup.
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Simulating rigid collisions among arbitrary shapes is notoriously difficult due to complex geometry and the strong non-linearity of the interactions. While graph neural network (GNN)-based models are effective at learning to simulate complex physical dynamics, such as fluids, cloth and articulated bodies, they have been less effective and efficient on rigid-body physics, except with very simple shapes. Existing methods that model collisions through the meshes' nodes are often inaccurate because they struggle when collisions occur on faces far from nodes. Alternative approaches that represent the geometry densely with many particles are prohibitively expensive for complex shapes. Here we introduce the Face Interaction Graph Network (FIGNet) which extends beyond GNN-based methods, and computes interactions between mesh faces, rather than nodes. Compared to learned node- and particle-based methods, FIGNet is around 4x more accurate in simulating complex shape interactions, while also 8x more computationally efficient on sparse, rigid meshes. Moreover, FIGNet can learn frictional dynamics directly from real-world data, and can be more accurate than analytical solvers given modest amounts of training data. FIGNet represents a key step forward in one of the few remaining physical domains which have seen little competition from learned simulators, and offers allied fields such as robotics, graphics and mechanical design a new tool for simulation and model-based planning.
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Large language models (LLMs) have been shown to be able to perform new tasks based on a few demonstrations or natural language instructions. While these capabilities have led to widespread adoption, most LLMs are developed by resource-rich organizations and are frequently kept from the public. As a step towards democratizing this powerful technology, we present BLOOM, a 176B-parameter open-access language model designed and built thanks to a collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer language model that was trained on the ROOTS corpus, a dataset comprising hundreds of sources in 46 natural and 13 programming languages (59 in total). We find that BLOOM achieves competitive performance on a wide variety of benchmarks, with stronger results after undergoing multitask prompted finetuning. To facilitate future research and applications using LLMs, we publicly release our models and code under the Responsible AI License.
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基于连续的潜在空间(例如变异自动编码器)的概率模型可以理解为无数混合模型,其中组件连续取决于潜在代码。它们具有用于生成和概率建模的表达性工具,但与可牵引的概率推断不符,即计算代表概率分布的边际和条件。同时,可以将概率模型(例如概率电路(PC))理解为层次离散混合模型,从而使它们可以执行精确的推断,但是与连续的潜在空间模型相比,它们通常显示出低于标准的性能。在本文中,我们研究了一种混合方法,即具有较小潜在尺寸的可拖动模型的连续混合物。尽管这些模型在分析上是棘手的,但基于一组有限的集成点,它们非常适合数值集成方案。有足够数量的集成点,近似值变得精确。此外,使用一组有限的集成点,可以将近似方法编译成PC中,以“在近似模型中的精确推断”执行。在实验中,我们表明这种简单的方案被证明非常有效,因为PC在许多标准密度估计基准上以这种方式为可拖动模型设定了新的最新模型。
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由于全景分割为输入中的每个像素提供了一个预测,因此,非标准和看不见的对象系统地导致了错误的输出。但是,在关键的环境中,针对分发样本的鲁棒性和角案件对于避免危险行为至关重要,例如忽略动物或道路上的货物丢失。由于驾驶数据集不能包含足够的数据点来正确采样基础分布的长尾巴,因此方法必须处理未知和看不见的方案才能安全部署。以前的方法是通过重新识别已经看到未标记的对象来针对此问题的一部分。在这项工作中,我们扩大了提出整体分割的范围:一项任务,以识别和将看不见的对象分为实例,而无需从未知数中学习,同时执行已知类别的全面分割。我们用U3HS解决了这个新问题,U3HS首先将未知数视为高度不确定的区域,然后将相应的实例感知嵌入到各个对象中。通过这样做,这是第一次使用未知对象进行综合分割,我们的U3HS未接受未知数据的训练,因此使对象类型的设置不受限制,并允许对整体场景理解。在两个公共数据集上进行了广泛的实验和比较,即CityScapes和作为转移的丢失和发现,证明了U3HS在挑战性的整体分段任务中的有效性,并具有竞争性的封闭式全盘分段性能。
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