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.

Spiking neural networks (SNNs) are promising brain-inspired energy-efficient models. Recent progress in training methods has enabled successful deep SNNs on large-scale tasks with low latency. Particularly, backpropagation through time (BPTT) with surrogate gradients (SG) is popularly used to achieve high performance in a very small number of time steps. However, it is at the cost of large memory consumption for training, lack of theoretical clarity for optimization, and inconsistency with the online property of biological learning and rules on neuromorphic hardware. Other works connect spike representations of SNNs with equivalent artificial neural network formulation and train SNNs by gradients from equivalent mappings to ensure descent directions. But they fail to achieve low latency and are also not online. In this work, we propose online training through time (OTTT) for SNNs, which is derived from BPTT to enable forward-in-time learning by tracking presynaptic activities and leveraging instantaneous loss and gradients. Meanwhile, we theoretically analyze and prove that gradients of OTTT can provide a similar descent direction for optimization as gradients based on spike representations under both feedforward and recurrent conditions. OTTT only requires constant training memory costs agnostic to time steps, avoiding the significant memory costs of BPTT for GPU training. Furthermore, the update rule of OTTT is in the form of three-factor Hebbian learning, which could pave a path for online on-chip learning. With OTTT, it is the first time that two mainstream supervised SNN training methods, BPTT with SG and spike representation-based training, are connected, and meanwhile in a biologically plausible form. Experiments on CIFAR-10, CIFAR-100, ImageNet, and CIFAR10-DVS demonstrate the superior performance of our method on large-scale static and neuromorphic datasets in small time steps.

基于图形卷积的方法已成功应用于同质图上的表示学习，其中具有相同标签或相似属性的节点往往相互连接。由于这些方法使用的图形卷积网络（GCN）的同义假设，它们不适合异质图，其中具有不同标记或不同属性的节点往往相邻。几种方法试图解决这个异质问题，但是它们没有改变GCN的基本聚合机制，因为它们依靠求和操作员来汇总邻近节点的信息，这隐含地遵守同质假设。在这里，我们介绍了一种新颖的聚合机制，并开发了基于随机步行聚集的图形神经网络（称为RAW-GNN）方法。提出的方法将随机步行策略与图神经网络集成在一起。新方法利用广度优先的随机步行搜索来捕获同质信息和深度优先搜索以收集异性信息。它用基于路径的社区取代了传统社区，并基于经常性神经网络引入了新的基于路径的聚合器。这些设计使RAW-GNN适用于同质图和异质图。广泛的实验结果表明，新方法在各种同质图和异质图上实现了最先进的性能。

关节2D心脏分割和3D体积重建是建立统计心脏解剖模型的基础，并了解运动模式的功能机制。但是，由于CINE MR和高主体间方差的平面分辨率低，精确分割心脏图像并重建3D体积是具有挑战性的。在这项研究中，我们提出了一个基于潜在空间的端到端框架DeepRecon，该框架会产生多个临床上基本的结果，包括准确的图像分割，合成高分辨率3D图像和3D重建体积。我们的方法确定了Cine图像的最佳潜在表示，其中包含心脏结构的准确语义信息。特别是，我们的模型共同生成具有准确的语义信息的合成图像，并使用最佳潜在表示对心脏结构进行分割。我们进一步探索了3D形状重建和4D运动模式通过不同的潜在空间操纵策略进行适应的下游应用。同时生成的高分辨率图像具有评估心脏形状和运动的高可解释价值。实验性结果证明了我们的有效性在多个方面的方法，包括2D分割，3D重建，下游4D运动模式适应性。

香草无监督的域适应方法倾向于用固定的神经体系结构优化模型，在现实世界中，这不是很实际的，因为目标数据通常由不同的资源有限的设备处理。因此，促进各种设备的建筑适应非常必要。在本文中，我们引入了一个简单的框架，可靠的域名适应，以通过重量分担模型库来改善跨域的概括，从中可以采样不同能力的模型，以适应不同的准确性效率折衷。该框架中的主要挑战在于同时提高模型库中众多模型的适应性。为了解决这个问题，我们开发了一种随机的集合蒸馏方法，以完全利用模型库中的互补知识进行模型间相互作用。然而，考虑到模型间相互作用与模型适应之间的优化冲突，我们将现有的BI-CLAPERIFIER域混淆体系结构扩大到优化分离的三级分类器对应物中。优化模型库后，通过我们提出的无监督性能评估指标利用体系结构的适应。在各种资源限制下，我们的框架超过了其他竞争方法，在多个基准测试方面的利润很大。还值得强调的是，即使计算复杂性降低到$ 1/64 $，我们的框架也可以保护仅源模型的性能提高。代码将在https://github.com/hikvision-research/slimda上找到。

CT图像中的椎骨定位，分割和识别是众多临床应用的关键。尽管近年来，深度学习策略已为该领域带来了重大改进，但由于其在培训数据集中的代表性不佳，过渡性和病理椎骨仍在困扰大多数现有方法。另外，提出的基于非学习的方法可以利用先验知识来处理这种特定情况。在这项工作中，我们建议将这两种策略结合起来。为此，我们引入了一个迭代循环，在该循环中，单个椎骨被递归地定位，分割和使用深网鉴定，而使用统计先验则实施解剖一致性。在此策略中，通过在图形模型中编码其配置来处理过渡性椎骨识别，该模型将局部深网预测汇总为解剖上一致的最终结果。我们的方法在Verse20挑战基准上取得了最新的结果，并且优于过渡性椎骨的所有方法以及对Verse19挑战基准的概括。此外，我们的方法可以检测和报告不满足解剖学一致性先验的不一致的脊柱区域。我们的代码和模型公开用于研究目的。

Despite significant progress in object categorization, in recent years, a number of important challenges remain; mainly, the ability to learn from limited labeled data and to recognize object classes within large, potentially open, set of labels. Zero-shot learning is one way of addressing these challenges, but it has only been shown to work with limited sized class vocabularies and typically requires separation between supervised and unsupervised classes, allowing former to inform the latter but not vice versa. We propose the notion of vocabulary-informed learning to alleviate the above mentioned challenges and address problems of supervised, zero-shot, generalized zero-shot and open set recognition using a unified framework. Specifically, we propose a weighted maximum margin framework for semantic manifold-based recognition that incorporates distance constraints from (both supervised and unsupervised) vocabulary atoms. Distance constraints ensure that labeled samples are projected closer to their correct prototypes, in the embedding space, than to others. We illustrate that resulting model shows improvements in supervised, zero-shot, generalized zero-shot, and large open set recognition, with up to 310K class vocabulary on Animal with Attributes and ImageNet datasets.

Deploying reliable deep learning techniques in interdisciplinary applications needs learned models to output accurate and ({even more importantly}) explainable predictions. Existing approaches typically explicate network outputs in a post-hoc fashion, under an implicit assumption that faithful explanations come from accurate predictions/classifications. We have an opposite claim that explanations boost (or even determine) classification. That is, end-to-end learning of explanation factors to augment discriminative representation extraction could be a more intuitive strategy to inversely assure fine-grained explainability, e.g., in those neuroimaging and neuroscience studies with high-dimensional data containing noisy, redundant, and task-irrelevant information. In this paper, we propose such an explainable geometric deep network dubbed as NeuroExplainer, with applications to uncover altered infant cortical development patterns associated with preterm birth. Given fundamental cortical attributes as network input, our NeuroExplainer adopts a hierarchical attention-decoding framework to learn fine-grained attentions and respective discriminative representations to accurately recognize preterm infants from term-born infants at term-equivalent age. NeuroExplainer learns the hierarchical attention-decoding modules under subject-level weak supervision coupled with targeted regularizers deduced from domain knowledge regarding brain development. These prior-guided constraints implicitly maximizes the explainability metrics (i.e., fidelity, sparsity, and stability) in network training, driving the learned network to output detailed explanations and accurate classifications. Experimental results on the public dHCP benchmark suggest that NeuroExplainer led to quantitatively reliable explanation results that are qualitatively consistent with representative neuroimaging studies.

Medical image segmentation (MIS) is essential for supporting disease diagnosis and treatment effect assessment. Despite considerable advances in artificial intelligence (AI) for MIS, clinicians remain skeptical of its utility, maintaining low confidence in such black box systems, with this problem being exacerbated by low generalization for out-of-distribution (OOD) data. To move towards effective clinical utilization, we propose a foundation model named EvidenceCap, which makes the box transparent in a quantifiable way by uncertainty estimation. EvidenceCap not only makes AI visible in regions of uncertainty and OOD data, but also enhances the reliability, robustness, and computational efficiency of MIS. Uncertainty is modeled explicitly through subjective logic theory to gather strong evidence from features. We show the effectiveness of EvidenceCap in three segmentation datasets and apply it to the clinic. Our work sheds light on clinical safe applications and explainable AI, and can contribute towards trustworthiness in the medical domain.

While inferring common actor states (such as position or velocity) is an important and well-explored task of the perception system aboard a self-driving vehicle (SDV), it may not always provide sufficient information to the SDV. This is especially true in the case of active emergency vehicles (EVs), where light-based signals also need to be captured to provide a full context. We consider this problem and propose a sequential methodology for the detection of active EVs, using an off-the-shelf CNN model operating at a frame level and a downstream smoother that accounts for the temporal aspect of flashing EV lights. We also explore model improvements through data augmentation and training with additional hard samples.