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.

我们介绍了ThreedWorld（TDW），是交互式多模态物理模拟的平台。 TDW能够模拟高保真感官数据和富裕的3D环境中的移动代理和对象之间的物理交互。独特的属性包括：实时近光 - 真实图像渲染;对象和环境库，以及他们定制的例程;有效构建新环境课程的生成程序;高保真音频渲染;各种材料类型的现实物理相互作用，包括布料，液体和可变形物体;可定制的代理体现AI代理商;并支持与VR设备的人类交互。 TDW的API使多个代理能够在模拟中进行交互，并返回一系列表示世界状态的传感器和物理数据。我们在计算机视觉，机器学习和认知科学中的新兴的研究方向上提供了通过TDW的初始实验，包括多模态物理场景理解，物理动态预测，多代理交互，像孩子一样学习的模型，并注意研究人类和神经网络。

Algorithms that involve both forecasting and optimization are at the core of solutions to many difficult real-world problems, such as in supply chains (inventory optimization), traffic, and in the transition towards carbon-free energy generation in battery/load/production scheduling in sustainable energy systems. Typically, in these scenarios we want to solve an optimization problem that depends on unknown future values, which therefore need to be forecast. As both forecasting and optimization are difficult problems in their own right, relatively few research has been done in this area. This paper presents the findings of the ``IEEE-CIS Technical Challenge on Predict+Optimize for Renewable Energy Scheduling," held in 2021. We present a comparison and evaluation of the seven highest-ranked solutions in the competition, to provide researchers with a benchmark problem and to establish the state of the art for this benchmark, with the aim to foster and facilitate research in this area. The competition used data from the Monash Microgrid, as well as weather data and energy market data. It then focused on two main challenges: forecasting renewable energy production and demand, and obtaining an optimal schedule for the activities (lectures) and on-site batteries that lead to the lowest cost of energy. The most accurate forecasts were obtained by gradient-boosted tree and random forest models, and optimization was mostly performed using mixed integer linear and quadratic programming. The winning method predicted different scenarios and optimized over all scenarios jointly using a sample average approximation method.

We describe a Physics-Informed Neural Network (PINN) that simulates the flow induced by the astronomical tide in a synthetic port channel, with dimensions based on the Santos - S\~ao Vicente - Bertioga Estuarine System. PINN models aim to combine the knowledge of physical systems and data-driven machine learning models. This is done by training a neural network to minimize the residuals of the governing equations in sample points. In this work, our flow is governed by the Navier-Stokes equations with some approximations. There are two main novelties in this paper. First, we design our model to assume that the flow is periodic in time, which is not feasible in conventional simulation methods. Second, we evaluate the benefit of resampling the function evaluation points during training, which has a near zero computational cost and has been verified to improve the final model, especially for small batch sizes. Finally, we discuss some limitations of the approximations used in the Navier-Stokes equations regarding the modeling of turbulence and how it interacts with PINNs.

Computational fluid dynamics (CFD) is a valuable asset for patient-specific cardiovascular-disease diagnosis and prognosis, but its high computational demands hamper its adoption in practice. Machine-learning methods that estimate blood flow in individual patients could accelerate or replace CFD simulation to overcome these limitations. In this work, we consider the estimation of vector-valued quantities on the wall of three-dimensional geometric artery models. We employ group-equivariant graph convolution in an end-to-end SE(3)-equivariant neural network that operates directly on triangular surface meshes and makes efficient use of training data. We run experiments on a large dataset of synthetic coronary arteries and find that our method estimates directional wall shear stress (WSS) with an approximation error of 7.6% and normalised mean absolute error (NMAE) of 0.4% while up to two orders of magnitude faster than CFD. Furthermore, we show that our method is powerful enough to accurately predict transient, vector-valued WSS over the cardiac cycle while conditioned on a range of different inflow boundary conditions. These results demonstrate the potential of our proposed method as a plugin replacement for CFD in the personalised prediction of hemodynamic vector and scalar fields.

自动面部识别是一个知名的研究领域。在该领域的最后三十年的深入研究中，已经提出了许多不同的面部识别算法。随着深度学习的普及及其解决各种不同问题的能力，面部识别研究人员集中精力在此范式下创建更好的模型。从2015年开始，最先进的面部识别就植根于深度学习模型。尽管有大规模和多样化的数据集可用于评估面部识别算法的性能，但许多现代数据集仅结合了影响面部识别的不同因素，例如面部姿势，遮挡，照明，面部表情和图像质量。当算法在这些数据集上产生错误时，尚不清楚哪些因素导致了此错误，因此，没有指导需要多个方向进行更多的研究。这项工作是我们以前在2014年开发的作品的后续作品，最终于2016年发表，显示了各种面部方面对面部识别算法的影响。通过将当前的最新技术与过去的最佳系统进行比较，我们证明了在强烈的遮挡下，某些类型的照明和强烈表达的面孔是深入学习算法所掌握的问题，而具有低分辨率图像的识别，极端的姿势变化和开放式识别仍然是一个开放的问题。为了证明这一点，我们使用六个不同的数据集和五种不同的面部识别算法以开源和可重现的方式运行一系列实验。我们提供了运行所有实验的源代码，这很容易扩展，因此在我们的评估中利用自己的深网只有几分钟的路程。

本文对三种项目调度算法进行了经验性能分析，该算法涉及最大化项目的净现值和无限制资源的净现值。所选算法是文献中最近引用的算法，是：递归搜索（RS），最陡峭的上升方法（SAA）和混合搜索（HS）。这项研究的主要动机是缺乏有关RS，SAA和HS算法的计算复杂性的知识，因为迄今为止的所有研究都显示了分析中的一些差距。此外，迄今为止执行的经验分析并未考虑到一种算法（HS）使用双重搜索策略的事实，该策略显着改善了该算法的性能，而其他算法则没有。为了获得公平的性能比较，我们将双重搜索策略实施到其他两种算法（RS和SAA）中，新算法称为递归搜索前进（RSFB）和最陡峭的上升趋势前进（SAAFB）（SAAFB） 。将算法RSFB，SAAFB和HS提交给具有三个不同项目网络抽样特征的阶乘实验。使用广义线性模型（GLM）统计建模技术分析了结果，该技术显示：a）RSFB，SAAFB和HS的一般计算成本； b）作为算法总成本的一部分，重新​​启动搜索的成本； c）算法结果的分布之间的统计学显着差异。

研究人员通常会采用数值方法来理解和预测海洋动力学，这是掌握环境现象的关键任务。在地形图很复杂，有关基础过程的知识不完整或应用程序至关重要的情况下，此类方法可能不适合。另一方面，如果观察到海洋动力学，则可以通过最近的机器学习方法来利用它们。在本文中，我们描述了一种数据驱动的方法，可以预测环境变量，例如巴西东南海岸的Santos-Sao Vicente-Bertioga estuarine系统的当前速度和海面高度。我们的模型通过连接最新的序列模型（LSTM和Transformers）以及关系模型（图神经网络）来利用时间和空间归纳偏见，以学习时间特征和空间特征，观察站点之间共享的关系。我们将结果与桑托斯运营预测系统（SOFS）进行比较。实验表明，我们的模型可以实现更好的结果，同时保持灵活性和很少的领域知识依赖性。

分布式的小型太阳能光伏（PV）系统正在以快速增加的速度安装。这可能会对分销网络和能源市场产生重大影响。结果，在不同时间分辨率和视野中，非常需要改善对这些系统发电的预测。但是，预测模型的性能取决于分辨率和地平线。在这种情况下，将多个模型的预测结合到单个预测中的预测组合（合奏）可能是鲁棒的。因此，在本文中，我们提供了对五个最先进的预测模型的性能以及在多个分辨率和视野下的现有预测组合的比较和见解。我们提出了一种基于粒子群优化（PSO）的预测组合方法，该方法将通过加权单个模型产生的预测来使预报掌握能够为手头的任务产生准确的预测。此外，我们将提出的组合方法的性能与现有的预测组合方法进行了比较。使用现实世界中的PV电源数据集进行了全面的评估，该数据集在美国三个位置的25个房屋中测得。在四种不同的分辨率和四个不同视野之间的结果表明，基于PSO的预测组合方法的表现优于使用任何单独的预测模型和其他预测组合的使用，而平均平均绝对规模误差降低了3.81％，而最佳性能则最佳性能单个个人模型。我们的方法使太阳预报员能够为其应用产生准确的预测，而不管预测分辨率或视野如何。

Inspired by progress in large-scale language modeling, we apply a similar approach towards building a single generalist agent beyond the realm of text outputs. The agent, which we refer to as Gato, works as a multi-modal, multi-task, multi-embodiment generalist policy. The same network with the same weights can play Atari, caption images, chat, stack blocks with a real robot arm and much more, deciding based on its context whether to output text, joint torques, button presses, or other tokens. In this report we describe the model and the data, and document the current capabilities of Gato.