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.

视觉变压器体系结构已显示在计算机视觉（CV）空间中具有竞争力，在该空间中，它在几个基准测试中剥夺了基于卷积的网络。然而，卷积神经网络（CNN）仍然是强化学习中表示模块的优先体系结构。在这项工作中，我们使用几种最先进的自我监督方法研究了视觉变压器预处理，并评估了该培训框架中的数据效率收益。我们提出了一种称为TOV-VICREG的新的自我监督的学习方法，该方法通过添加时间订单验证任务来扩展Vicreg，以更好地捕获观测值之间的时间关系。此外，我们在样本效率方面通过Atari游戏评估了所得编码器。我们的结果表明，当通过TOV-VICREG进行预估计时，视觉变压器的表现优于其他自我监督的方法，但仍在努力克服CNN。尽管如此，我们在十场比赛中的两场比赛中，我们能够胜过CNN，在我们执行100k台阶评估中。最终，我们认为，深入强化学习（DRL）中的这种方法可能是实现自然语言处理和计算机视觉中所见的新表现的关键。源代码将提供：https：//github.com/mgoulao/tov-vicreg

使用规划算法和神经网络模型的基于模型的强化学习范例最近在不同的应用中实现了前所未有的结果，导致现在被称为深度增强学习的内容。这些代理非常复杂，涉及多个组件，可能会为研究产生挑战的因素。在这项工作中，我们提出了一个适用于这些类型代理的新模块化软件架构，以及一组建筑块，可以轻松重复使用和组装，以构建基于模型的增强学习代理。这些构建块包括规划算法，策略和丢失功能。我们通过将多个这些构建块组合实现和测试经过针对三种不同的测试环境的代理来说明这种架构的使用：Cartpole，Minigrid和Tictactoe。在我们的实施中提供的一个特定的规划算法，并且以前没有用于加强学习，我们称之为Imperage Minimax，在三个测试环境中取得了良好的效果。用这种架构进行的实验表明，规划算法，政策和损失函数的最佳组合依赖性严重问题。该结果提供了证据表明，拟议的架构是模块化和可重复使用的，对想要研究新环境和技术的强化学习研究人员有用。

注意机制对研究界提出了重大兴趣，因为他们承诺改善神经网络架构的表现。但是，在任何特定的问题中，我们仍然缺乏主要的方法来选择导致保证改进的具体机制和超参数。最近，已经提出了自我关注并广泛用于变压器 - 类似的架构中，导致某些应用中的重大突破。在这项工作中，我们专注于两种形式的注意机制：注意模块和自我关注。注意模块用于重新重量每个层输入张量的特征。不同的模块具有不同的方法，可以在完全连接或卷积层中执行此重复。研究的注意力模型是完全模块化的，在这项工作中，它们将与流行的Reset架构一起使用。自我关注，最初在自然语言处理领域提出，可以将所有项目与输入序列中的所有项目相关联。自我关注在计算机视觉中越来越受欢迎，其中有时与卷积层相结合，尽管最近的一些架构与卷曲完全消失。在这项工作中，我们研究并执行了在特定计算机视觉任务中许多不同关注机制的客观的比较，在广泛使用的皮肤癌MNIST数据集中的样本分类。结果表明，关注模块有时会改善卷积神经网络架构的性能，也是这种改进虽然明显且统计学意义，但在不同的环境中并不一致。另一方面，通过自我关注机制获得的结果表明了一致和显着的改进，即使在具有减少数量的参数的架构中，也可以实现最佳结果。

这项工作提出了使用遗传算法（GA）在追踪和识别使用计算机断层扫描（CT）图像的人心包轮廓的过程中。我们假设心包的每个切片都可以通过椭圆建模，椭圆形需要最佳地确定其参数。最佳椭圆将是紧随心包轮廓的紧密椭圆形，因此，将人心脏的心外膜和纵隔脂肪适当地分开。追踪和自动识别心包轮廓辅助药物的医学诊断。通常，由于所需的努力，此过程是手动完成或根本不完成的。此外，检测心包可能会改善先前提出的自动化方法，这些方法将与人心脏相关的两种类型的脂肪分开。这些脂肪的量化提供了重要的健康风险标记信息，因为它们与某些心血管病理的发展有关。最后，我们得出的结论是，GA在可行数量的处理时间内提供了令人满意的解决方案。

本文基于Loeffler离散余弦变换（DCT）算法引入了矩阵参数化方法。结果，提出了一类新的八点DCT近似值，能够统一文献中几个八点DCT近似的数学形式主义。帕累托效率的DCT近似是通过多准则优化获得的，其中考虑了计算复杂性，接近性和编码性能。有效的近似及其缩放的16和32点版本嵌入了图像和视频编码器中，包括类似JPEG的编解码器以及H.264/AVC和H.265/HEVC标准。将结果与未修饰的标准编解码器进行比较。在Xilinx VLX240T FPGA上映射并实现了有效的近似值，并评估了面积，速度和功耗。

Context-aware decision support in the operating room can foster surgical safety and efficiency by leveraging real-time feedback from surgical workflow analysis. Most existing works recognize surgical activities at a coarse-grained level, such as phases, steps or events, leaving out fine-grained interaction details about the surgical activity; yet those are needed for more helpful AI assistance in the operating room. Recognizing surgical actions as triplets of <instrument, verb, target> combination delivers comprehensive details about the activities taking place in surgical videos. This paper presents CholecTriplet2021: an endoscopic vision challenge organized at MICCAI 2021 for the recognition of surgical action triplets in laparoscopic videos. The challenge granted private access to the large-scale CholecT50 dataset, which is annotated with action triplet information. In this paper, we present the challenge setup and assessment of the state-of-the-art deep learning methods proposed by the participants during the challenge. A total of 4 baseline methods from the challenge organizers and 19 new deep learning algorithms by competing teams are presented to recognize surgical action triplets directly from surgical videos, achieving mean average precision (mAP) ranging from 4.2% to 38.1%. This study also analyzes the significance of the results obtained by the presented approaches, performs a thorough methodological comparison between them, in-depth result analysis, and proposes a novel ensemble method for enhanced recognition. Our analysis shows that surgical workflow analysis is not yet solved, and also highlights interesting directions for future research on fine-grained surgical activity recognition which is of utmost importance for the development of AI in surgery.

While the brain connectivity network can inform the understanding and diagnosis of developmental dyslexia, its cause-effect relationships have not yet enough been examined. Employing electroencephalography signals and band-limited white noise stimulus at 4.8 Hz (prosodic-syllabic frequency), we measure the phase Granger causalities among channels to identify differences between dyslexic learners and controls, thereby proposing a method to calculate directional connectivity. As causal relationships run in both directions, we explore three scenarios, namely channels' activity as sources, as sinks, and in total. Our proposed method can be used for both classification and exploratory analysis. In all scenarios, we find confirmation of the established right-lateralized Theta sampling network anomaly, in line with the temporal sampling framework's assumption of oscillatory differences in the Theta and Gamma bands. Further, we show that this anomaly primarily occurs in the causal relationships of channels acting as sinks, where it is significantly more pronounced than when only total activity is observed. In the sink scenario, our classifier obtains 0.84 and 0.88 accuracy and 0.87 and 0.93 AUC for the Theta and Gamma bands, respectively.

There are multiple scales of abstraction from which we can describe the same image, depending on whether we are focusing on fine-grained details or a more global attribute of the image. In brain mapping, learning to automatically parse images to build representations of both small-scale features (e.g., the presence of cells or blood vessels) and global properties of an image (e.g., which brain region the image comes from) is a crucial and open challenge. However, most existing datasets and benchmarks for neuroanatomy consider only a single downstream task at a time. To bridge this gap, we introduce a new dataset, annotations, and multiple downstream tasks that provide diverse ways to readout information about brain structure and architecture from the same image. Our multi-task neuroimaging benchmark (MTNeuro) is built on volumetric, micrometer-resolution X-ray microtomography images spanning a large thalamocortical section of mouse brain, encompassing multiple cortical and subcortical regions. We generated a number of different prediction challenges and evaluated several supervised and self-supervised models for brain-region prediction and pixel-level semantic segmentation of microstructures. Our experiments not only highlight the rich heterogeneity of this dataset, but also provide insights into how self-supervised approaches can be used to learn representations that capture multiple attributes of a single image and perform well on a variety of downstream tasks. Datasets, code, and pre-trained baseline models are provided at: https://mtneuro.github.io/ .

The ability to convert reciprocating, i.e., alternating, actuation into rotary motion using linkages is hindered fundamentally by their poor torque transmission capability around kinematic singularity configurations. Here, we harness the elastic potential energy of a linear spring attached to the coupler link of four-bar mechanisms to manipulate force transmission around the kinematic singularities. We developed a theoretical model to explore the parameter space for proper force transmission in slider-crank and rocker-crank four-bar kinematics. Finally, we verified the proposed model and methodology by building and testing a macro-scale prototype of a slider-crank mechanism. We expect this approach to enable the development of small-scale rotary engines and robotic devices with closed kinematic chains dealing with serial kinematic singularities, such as linkages and parallel manipulators.