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.

Physics-informed neural networks (PINNs) have lately received significant attention as a representative deep learning-based technique for solving partial differential equations (PDEs). Most fully connected network-based PINNs use automatic differentiation to construct loss functions that suffer from slow convergence and difficult boundary enforcement. In addition, although convolutional neural network (CNN)-based PINNs can significantly improve training efficiency, CNNs have difficulty in dealing with irregular geometries with unstructured meshes. Therefore, we propose a novel framework based on graph neural networks (GNNs) and radial basis function finite difference (RBF-FD). We introduce GNNs into physics-informed learning to better handle irregular domains with unstructured meshes. RBF-FD is used to construct a high-precision difference format of the differential equations to guide model training. Finally, we perform numerical experiments on Poisson and wave equations on irregular domains. We illustrate the generalizability, accuracy, and efficiency of the proposed algorithms on different PDE parameters, numbers of collection points, and several types of RBFs.

Although synthetic aperture imaging (SAI) can achieve the seeing-through effect by blurring out off-focus foreground occlusions while recovering in-focus occluded scenes from multi-view images, its performance is often deteriorated by dense occlusions and extreme lighting conditions. To address the problem, this paper presents an Event-based SAI (E-SAI) method by relying on the asynchronous events with extremely low latency and high dynamic range acquired by an event camera. Specifically, the collected events are first refocused by a Refocus-Net module to align in-focus events while scattering out off-focus ones. Following that, a hybrid network composed of spiking neural networks (SNNs) and convolutional neural networks (CNNs) is proposed to encode the spatio-temporal information from the refocused events and reconstruct a visual image of the occluded targets. Extensive experiments demonstrate that our proposed E-SAI method can achieve remarkable performance in dealing with very dense occlusions and extreme lighting conditions and produce high-quality images from pure events. Codes and datasets are available at https://dvs-whu.cn/projects/esai/.

3D object detection received increasing attention in autonomous driving recently. Objects in 3D scenes are distributed with diverse orientations. Ordinary detectors do not explicitly model the variations of rotation and reflection transformations. Consequently, large networks and extensive data augmentation are required for robust detection. Recent equivariant networks explicitly model the transformation variations by applying shared networks on multiple transformed point clouds, showing great potential in object geometry modeling. However, it is difficult to apply such networks to 3D object detection in autonomous driving due to its large computation cost and slow reasoning speed. In this work, we present TED, an efficient Transformation-Equivariant 3D Detector to overcome the computation cost and speed issues. TED first applies a sparse convolution backbone to extract multi-channel transformation-equivariant voxel features; and then aligns and aggregates these equivariant features into lightweight and compact representations for high-performance 3D object detection. On the highly competitive KITTI 3D car detection leaderboard, TED ranked 1st among all submissions with competitive efficiency.

Image super-resolution is a common task on mobile and IoT devices, where one often needs to upscale and enhance low-resolution images and video frames. While numerous solutions have been proposed for this problem in the past, they are usually not compatible with low-power mobile NPUs having many computational and memory constraints. In this Mobile AI challenge, we address this problem and propose the participants to design an efficient quantized image super-resolution solution that can demonstrate a real-time performance on mobile NPUs. The participants were provided with the DIV2K dataset and trained INT8 models to do a high-quality 3X image upscaling. The runtime of all models was evaluated on the Synaptics VS680 Smart Home board with a dedicated edge NPU capable of accelerating quantized neural networks. All proposed solutions are fully compatible with the above NPU, demonstrating an up to 60 FPS rate when reconstructing Full HD resolution images. A detailed description of all models developed in the challenge is provided in this paper.

Single-cell technologies are revolutionizing the entire field of biology. The large volumes of data generated by single-cell technologies are high-dimensional, sparse, heterogeneous, and have complicated dependency structures, making analyses using conventional machine learning approaches challenging and impractical. In tackling these challenges, deep learning often demonstrates superior performance compared to traditional machine learning methods. In this work, we give a comprehensive survey on deep learning in single-cell analysis. We first introduce background on single-cell technologies and their development, as well as fundamental concepts of deep learning including the most popular deep architectures. We present an overview of the single-cell analytic pipeline pursued in research applications while noting divergences due to data sources or specific applications. We then review seven popular tasks spanning through different stages of the single-cell analysis pipeline, including multimodal integration, imputation, clustering, spatial domain identification, cell-type deconvolution, cell segmentation, and cell-type annotation. Under each task, we describe the most recent developments in classical and deep learning methods and discuss their advantages and disadvantages. Deep learning tools and benchmark datasets are also summarized for each task. Finally, we discuss the future directions and the most recent challenges. This survey will serve as a reference for biologists and computer scientists, encouraging collaborations.

最近，基于云的图形卷积网络（GCN）在许多对隐私敏感的应用程序（例如个人医疗保健和金融系统）中表现出了巨大的成功和潜力。尽管在云上具有很高的推理准确性和性能，但在GCN推理中保持数据隐私，这对于这些实际应用至关重要，但仍未得到探索。在本文中，我们对此进行了初步尝试，并开发了$ \ textit {cryptogcn} $ - 基于GCN推理框架的同型加密（HE）。我们方法成功的关键是减少HE操作的巨大计算开销，这可能比明文空间中的同行高的数量级。为此，我们开发了一种方法，可以有效利用GCN推断中基质操作的稀疏性，从而大大减少计算开销。具体而言，我们提出了一种新型的AMA数据格式方法和相关的空间卷积方法，该方法可以利用复杂的图结构并在HE计算中执行有效的矩阵矩阵乘法，从而大大减少HE操作。我们还开发了一个合作式框架，该框架可以通过明智的修剪和GCN中激活模块的多项式近似来探索准确性，安全级别和计算开销之间的交易折扣。基于NTU-Xview骨架关节数据集，即，据我们所知，最大的数据集对同型的评估，我们的实验结果表明，$ \ textit {cryptogcn} $均优胜于最先进的解决方案。同构操作的延迟和数量，即在延迟上达到3.10 $ \ times $加速，并将总代态操作数量减少77.4 \％，而准确度的较小精度损失为1-1.5 $ \％$。

开放世界对象检测是一个更具笼统和挑战性的目标，旨在识别和本地化由任意类别名称描述的对象。最近的工作GLIP通过将检测数据集的所有类别名称连接到句子中，从而将此问题作为接地问题，从而导致类别名称之间的效率低下的相互作用。本文介绍了Distclip，这是一种通过诉诸于设计概念词典的知识富集，是一种平行的视觉概念训练预训练方法，用于开放世界检测。为了提高学习效率，我们提出了一种新型的并行概念公式，该公式分别提取概念，以更好地利用异质数据集（即检测，接地和图像文本对）进行培训。我们进一步设计了来自各种在线资源和检测数据集的概念字典〜（带有描述），以提供每个概念的先验知识。通过用描述丰富这些概念，我们明确地建立了各种概念之间的关系，以促进开放域学习。所提出的概念词典进一步用于提供足够的负面概念，用于构建单词区域对齐损失\，并完成图像对文本对数据标题中缺少描述的对象的标签。所提出的框架显示出强烈的零射击性能性能，例如，在LVIS数据集上，我们的DETCLIP-T优于9.9％的地图GLIPT-T优于GLIP-T，并且与完全避免的型号相比，稀有类别的稀有类别提高了13.5％。作为我们的。

玻璃在现实世界中非常普遍。受玻璃区域的不确定性以及玻璃背后的各种复杂场景的影响，玻璃的存在对许多计算机视觉任务构成了严重的挑战，从而使玻璃分割成为重要的计算机视觉任务。玻璃没有自己的视觉外观，而只能传输/反映其周围环境的外观，从而与其他常见对象根本不同。为了解决此类具有挑战性的任务，现有方法通常会探索并结合深网络中不同特征级别的有用线索。由于存在级别不同的特征之间的特征差距，即，深层特征嵌入了更多高级语义，并且更好地定位目标对象，而浅层特征具有更大的空间尺寸，并保持更丰富，更详细的低级信息，因此，将这些特征融合到天真的融合将导致亚最佳溶液。在本文中，我们将有效的特征融合到两个步骤中，以朝着精确的玻璃分割。首先，我们试图通过开发可区分性增强（DE）模块来弥合不同级别特征之间的特征差距，该模块使特定于级别的特征成为更具歧视性的表示，从而减轻了融合不兼容的特征。其次，我们设计了一个基于焦点和探索的融合（FEBF）模块，以通过突出显示常见并探索级别差异特征之间的差异，从而在融合过程中丰富挖掘有用的信息。

热应力和变形的快速分析在热控制措施和卫星结构设计的优化中起着关键作用。为了实现卫星主板的实时热应力和热变形分析，本文提出了一种新型的多任务注意UNET（MTA-UNET）神经网络，将多任务学习（MTL）和U-NET的优势结合在一起注意机制。此外，在训练过程中使用了物理知识的策略，其中部分微分方程（PDE）被整合到损失函数中作为残留项。最后，将基于不确定性的损失平衡方法应用于重量的多个培训任务的不同损失功能。实验结果表明，与单任务学习（STL）模型相比，提出的MTA-UNET有效提高了多个物理任务的预测准确性。此外，物理信息的方法在每个任务的预测中的错误较小，尤其是在小型数据集上。代码可以在：\ url {https://github.com/komorebitso/mta-unet}下载。