KL-regularized reinforcement learning from expert demonstrations has proved successful in improving the sample efficiency of deep reinforcement learning algorithms, allowing them to be applied to challenging physical real-world tasks. However, we show that KL-regularized reinforcement learning with behavioral reference policies derived from expert demonstrations can suffer from pathological training dynamics that can lead to slow, unstable, and suboptimal online learning. We show empirically that the pathology occurs for commonly chosen behavioral policy classes and demonstrate its impact on sample efficiency and online policy performance. Finally, we show that the pathology can be remedied by non-parametric behavioral reference policies and that this allows KL-regularized reinforcement learning to significantly outperform state-of-the-art approaches on a variety of challenging locomotion and dexterous hand manipulation tasks.

The recent advent of large language models - large neural networks trained on a simple predictive objective over a massive corpus of natural language - has reinvigorated debate over whether human cognitive capacities might emerge in such generic models given sufficient training data. Of particular interest is the ability of these models to reason about novel problems zero-shot, without any direct training on those problems. In human cognition, this capacity is closely tied to an ability to reason by analogy. Here, we performed a direct comparison between human reasoners and a large language model (GPT-3) on a range of analogical tasks, including a novel text-based matrix reasoning task closely modeled on Raven's Progressive Matrices. We found that GPT-3 displayed a surprisingly strong capacity for abstract pattern induction, matching or even surpassing human capabilities in most settings. Our results indicate that large language models such as GPT-3 have acquired an emergent ability to find zero-shot solutions to a broad range of analogy problems.

The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.

By transferring knowledge from large, diverse, task-agnostic datasets, modern machine learning models can solve specific downstream tasks either zero-shot or with small task-specific datasets to a high level of performance. While this capability has been demonstrated in other fields such as computer vision, natural language processing or speech recognition, it remains to be shown in robotics, where the generalization capabilities of the models are particularly critical due to the difficulty of collecting real-world robotic data. We argue that one of the keys to the success of such general robotic models lies with open-ended task-agnostic training, combined with high-capacity architectures that can absorb all of the diverse, robotic data. In this paper, we present a model class, dubbed Robotics Transformer, that exhibits promising scalable model properties. We verify our conclusions in a study of different model classes and their ability to generalize as a function of the data size, model size, and data diversity based on a large-scale data collection on real robots performing real-world tasks. The project's website and videos can be found at robotics-transformer.github.io

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.

受到人类在不依赖视觉的情况下感知陌生物体表面质地的能力的启发，触觉感可以在机器人探索环境的过程中起着至关重要的作用，尤其是在某些场景中，视力难以应用或闭塞是不可避免地存在。现有的触觉表面重建方法依赖外部传感器或具有强大的先前假设，这将限制其应用程序场景并使操作更加复杂。本文提出了一种表面重建算法，该算法仅使用基于新的触觉传感器，其中不熟悉的物体的表面结构由多个触觉测量重建。与现有算法相比，提出的算法不依赖外部设备，而是专注于提高大规模对象表面的重建精度。为了使重建精度很容易受到采样压力的影响，我们提出了一种校正算法以使其适应它。从多次接触产生的多帧触觉烙印可以通过共同使用点云注册算法，基于深度学习的环闭合检测算法和姿势图优化算法来准确地重建全局对象表面。实验验证所提出的算法可以在重建交互式对象表面并为机器人提供准确的触觉信息以了解周围环境时实现毫米级的精度。

ICECUBE是一种用于检测1 GEV和1 PEV之间大气和天体中微子的光学传感器的立方公斤阵列，该阵列已部署1.45 km至2.45 km的南极的冰盖表面以下1.45 km至2.45 km。来自ICE探测器的事件的分类和重建在ICeCube数据分析中起着核心作用。重建和分类事件是一个挑战，这是由于探测器的几何形状，不均匀的散射和冰中光的吸收，并且低于100 GEV的光，每个事件产生的信号光子数量相对较少。为了应对这一挑战，可以将ICECUBE事件表示为点云图形，并将图形神经网络（GNN）作为分类和重建方法。 GNN能够将中微子事件与宇宙射线背景区分开，对不同的中微子事件类型进行分类，并重建沉积的能量，方向和相互作用顶点。基于仿真，我们提供了1-100 GEV能量范围的比较与当前ICECUBE分析中使用的当前最新最大似然技术，包括已知系统不确定性的影响。对于中微子事件分类，与当前的IceCube方法相比，GNN以固定的假阳性速率（FPR）提高了信号效率的18％。另外，GNN在固定信号效率下将FPR的降低超过8（低于半百分比）。对于能源，方向和相互作用顶点的重建，与当前最大似然技术相比，分辨率平均提高了13％-20％。当在GPU上运行时，GNN能够以几乎是2.7 kHz的中位数ICECUBE触发速率的速率处理ICECUBE事件，这打开了在在线搜索瞬态事件中使用低能量中微子的可能性。

强化学习（RL）为可以在现实世界中自主互动的培训代理提供了潜力。但是，一个关键限制是RL算法对核心超参数和网络体系结构选择的脆弱性。此外，诸如不断发展的训练数据和增加的代理复杂性等非平稳性意味着不同的超参数和体系结构在不同的训练点上可能是最佳的。这激发了Autorl，这是一种试图自动化这些设计选择的方法。一类突出的Autorl方法是基于人群的培训（PBT），这在几个大型设置中导致了令人印象深刻的表现。在本文中，我们介绍了PBT式方法中的两项新创新。首先，我们采用基于信任区域的贝叶斯优化，从而可以全面覆盖高维混合参数搜索空间。其次，我们表明，使用世代相传，我们还可以在一次训练中共同学习体系结构和超参数。利用新的高度可行的Brax物理引擎，我们表明这些创新导致了巨大的性能增长，在即时学习整个配置的同时，大大优于调谐基线。代码可在https://github.com/xingchenwan/bgpbt上找到。

分配转移或培训数据和部署数据之间的不匹配是在高风险工业应用中使用机器学习的重要障碍，例如自动驾驶和医学。这需要能够评估ML模型的推广以及其不确定性估计的质量。标准ML基线数据集不允许评估这些属性，因为培训，验证和测试数据通常相同分布。最近，已经出现了一系列专用基准测试，其中包括分布匹配和转移的数据。在这些基准测试中，数据集在任务的多样性以及其功能的数据模式方面脱颖而出。虽然大多数基准测试由2D图像分类任务主导，但Shifts包含表格天气预测，机器翻译和车辆运动预测任务。这使得可以评估模型的鲁棒性属性，并可以得出多种工业规模的任务以及通用或直接适用的特定任务结论。在本文中，我们扩展了偏移数据集，其中两个数据集来自具有高社会重要性的工业高风险应用程序。具体而言，我们考虑了3D磁共振脑图像中白质多发性硬化病变的分割任务以及海洋货物容器中功耗的估计。两项任务均具有无处不在的分配变化和由于错误成本而构成严格的安全要求。这些新数据集将使研究人员能够进一步探索新情况下的强大概括和不确定性估计。在这项工作中，我们提供了两个任务的数据集和基线结果的描述。

离线强化学习在利用大型预采用的数据集进行政策学习方面表现出了巨大的希望，使代理商可以放弃经常廉价的在线数据收集。但是，迄今为止，离线强化学习的探索相对较小，并且缺乏对剩余挑战所在的何处的了解。在本文中，我们试图建立简单的基线以在视觉域中连续控制。我们表明，对两个基于最先进的在线增强学习算法，Dreamerv2和DRQ-V2进行了简单的修改，足以超越事先工作并建立竞争性的基准。我们在现有的离线数据集中对这些算法进行了严格的评估，以及从视觉观察结果中进行离线强化学习的新测试台，更好地代表现实世界中离线增强学习问题中存在的数据分布，并开放我们的代码和数据以促进此方面的进度重要领域。最后，我们介绍并分析了来自视觉观察的离线RL所独有的几个关键Desiderata，包括视觉分散注意力和动态视觉上可识别的变化。