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.

This paper is a technical overview of DeepMind and Google's recent work on reinforcement learning for controlling commercial cooling systems. Building on expertise that began with cooling Google's data centers more efficiently, we recently conducted live experiments on two real-world facilities in partnership with Trane Technologies, a building management system provider. These live experiments had a variety of challenges in areas such as evaluation, learning from offline data, and constraint satisfaction. Our paper describes these challenges in the hope that awareness of them will benefit future applied RL work. We also describe the way we adapted our RL system to deal with these challenges, resulting in energy savings of approximately 9% and 13% respectively at the two live experiment sites.

频率调制连续波（FMCW）LIDAR是一种最近新兴的技术，可通过多普勒效应效率进行每次返回的瞬时相对径向速度测量。在这封信中，我们使用这些多普勒速度测量值从FMCW激光雷达（FMCW Lidar）介绍了第一个连续的一次性绕线算法算法，以帮助几何变性环境中的探测率。我们应用现有的连续时间框架，该框架使用高斯工艺回归有效地估算车辆轨迹，以补偿由于任何机械驱动的激光雷达（FMCW和非FMCW）的扫描性质而引起的运动失真。我们在几个现实世界数据集上评估了我们提出的算法，包括我们收集的公开可用数据集和数据集。我们的算法优于也使用多普勒速度测量值的唯一现有方法，我们研究了包括此额外信息在内的困难条件，可大大提高性能。我们还证明了在标称条件下使用多普勒速度测量值的情况下，仅在有和不使用多普勒速度测量的情况下，仅激光射击的前进量的最新性能。该项目的代码可以在以下网址找到：https：//github.com/utiasasrl/steam_icp。

神经网络在压缩体积数据以进行科学可视化方面表现出巨大的潜力。但是，由于训练和推断的高成本，此类体积神经表示仅应用于离线数据处理和非交互式渲染。在本文中，我们证明，通过同时利用现代的GPU张量核心，本地CUDA神经网络框架以及在线培训，我们可以使用体积神经表示来实现高性能和高效率交互式射线追踪。此外，我们的方法是完全概括的，可以适应时变的数据集。我们提出了三种用于在线培训的策略，每种策略都利用GPU，CPU和核心流程技术的不同组合。我们还开发了三个渲染实现，允许交互式射线跟踪与实时卷解码，示例流和幕后神经网络推断相结合。我们证明，我们的体积神经表示可以扩展到Terascale，以进行常规网格体积可视化，并可以轻松地支持不规则的数据结构，例如OpenVDB，非结构化，AMR和粒子体积数据。

语言模型既展示了定量的改进，又展示了新的定性功能，随着规模的增加。尽管它们具有潜在的变革性影响，但这些新能力的特征却很差。为了为未来的研究提供信息，为破坏性的新模型能力做准备，并改善社会有害的效果，至关重要的是，我们必须了解目前和近乎未来的能力和语言模型的局限性。为了应对这一挑战，我们介绍了超越模仿游戏基准（Big Bench）。 Big Bench目前由204个任务组成，由132家机构的442位作者贡献。任务主题是多样的，从语言学，儿童发展，数学，常识性推理，生物学，物理学，社会偏见，软件开发等等。 Big-Bench专注于被认为超出当前语言模型的功能的任务。我们评估了OpenAI的GPT型号，Google内部密集变压器体系结构和大型基础上的开关稀疏变压器的行为，跨越了数百万到数十亿个参数。此外，一个人类专家评估者团队执行了所有任务，以提供强大的基准。研究结果包括：模型性能和校准都随规模改善，但绝对的术语（以及与评估者的性能相比）；在模型类中的性能非常相似，尽管带有稀疏性。逐渐和预测的任务通常涉及大量知识或记忆成分，而在临界规模上表现出“突破性”行为的任务通常涉及多个步骤或组成部分或脆性指标；社交偏见通常会随着含糊不清的环境而随着规模而增加，但这可以通过提示来改善。

败血症是危及生命的医疗紧急情况，这是全世界死亡的主要原因，也是美国死亡率的第二大原因。研究综合脓毒症系统的最佳控制处理或干预策略是降低死亡率的关键。为此目的，首先，本文提高了我们以前的工作中提出的复杂非线性败血症模型。然后，为每个SEPSIS子系统进行分叉分析，以研究某些系统参数下的模型行为。分叉分析结果还进一步表明了控制治疗和干预治疗的必要性。如果SEPSIS系统在某些参数和初始系统值设置下没有添加任何控件，系统将随着时间的推移而进行持续存在的炎症结果。因此，我们将复杂的改进的非线性败血症模型发展成败血症最优控制模型，然后使用现有诊所实践建议的一些有效的生物标志物作为衡量败血症的发展的优化目标函数。除此之外，还引入了通过组合反复性神经网络（RNN-BO算法）的贝叶斯优化算法来预测研究的败声最优控制系统的最佳控制策略。来自其他优化算法的RNN-BO算法之间的差异是，一旦给定任何新的初始系统值设置（初始值与患者的初始条件相关），则RNN-BO算法能够快速预测相应的时间序列基于任何新败血症患者的历史最佳控制数据的最佳控制。为了证明RNN-BO算法在复杂非线性SEPSIS系统上解决最佳控制解决方案的效力和效率，通过与本文中的其他优化算法进行比较来实现一些数值模拟。

贝叶斯优化算法已成为非线性全球优化问题和许多机器学习应用的有希望的方法。在过去的几年里，提出了改进和增强，他们已经提出了一些有希望的结果，在解决复杂的动态问题，客观函数计算昂贵的普通微分方程的系统来评估。此外，贝叶斯优化算法的直接实现仅适用于10-20维度的优化问题。本文提出的研究提出了一种新的高维贝叶斯优化算法，其结合了经常性神经网络，预计将预测高维或时间序列决策模型的全局优化问题的最佳解决方案。所提出的RNN-BO算法可以解决较低尺寸空间中的最佳控制问题，然后使用经常性神经网络从历史数据学习，以了解历史最佳解决方案数据，并预测任何新的初始系统值设置的最佳控制策略。此外，准确且快速地提供最佳控制策略对于有效和有效地控制疫情，同时最小化相关的财务成本至关重要。因此，为了验证所提出的算法的有效性，对确定性SEIR流行病模型和随机SIS最优控制模型进行计算实验。最后，我们还讨论了不同数量的RNN层和培训时代对解决方案质量与相关计算努力之间的权衡的影响。

考虑到人类行为的例子，我们考虑在多种代理决策问题中建立强大但人类的政策的任务。仿制学习在预测人类行为方面有效，但可能与专家人类的实力不符，而自助学习和搜索技术（例如，alphakero）导致强大的性能，但可能会产生难以理解和协调的政策。我们在国际象棋中显示，并通过应用Monte Carlo树搜索产生具有更高人为预测准确性的策略并比仿制政策更强大的kl差异，基于kl发散的正规化搜索策略。然后我们介绍一种新的遗憾最小化算法，该算法基于来自模仿的政策的KL发散规范，并显示将该算法应用于无按压外交产生的策略，使得在基本上同时保持与模仿学习相同的人类预测准确性的策略更强。

Springs are efficient in storing and returning elastic potential energy but are unable to hold the energy they store in the absence of an external load. Lockable springs use clutches to hold elastic potential energy in the absence of an external load but have not yet been widely adopted in applications, partly because clutches introduce design complexity, reduce energy efficiency, and typically do not afford high-fidelity control over the energy stored by the spring. Here, we present the design of a novel lockable compression spring that uses a small capstan clutch to passively lock a mechanical spring. The capstan clutch can lock up to 1000 N force at any arbitrary deflection, unlock the spring in less than 10 ms with a control force less than 1 % of the maximal spring force, and provide an 80 % energy storage and return efficiency (comparable to a highly efficient electric motor operated at constant nominal speed). By retaining the form factor of a regular spring while providing high-fidelity locking capability even under large spring forces, the proposed design could facilitate the development of energy-efficient spring-based actuators and robots.

Springs can provide force at zero net energy cost by recycling negative mechanical work to benefit motor-driven robots or spring-augmented humans. However, humans have limited force and range of motion, and motors have a limited ability to produce force. These limits constrain how much energy a conventional spring can store and, consequently, how much assistance a spring can provide. In this paper, we introduce an approach to accumulating negative work in assistive springs over several motion cycles. We show that, by utilizing a novel floating spring mechanism, the weight of a human or robot can be used to iteratively increase spring compression, irrespective of the potential energy stored by the spring. Decoupling the force required to compress a spring from the energy stored by a spring advances prior works, and could enable spring-driven robots and humans to perform physically demanding tasks without the use of large actuators.