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.

Photometric differences are widely used as supervision signals to train neural networks for estimating depth and camera pose from unlabeled monocular videos. However, this approach is detrimental for model optimization because occlusions and moving objects in a scene violate the underlying static scenario assumption. In addition, pixels in textureless regions or less discriminative pixels hinder model training. To solve these problems, in this paper, we deal with moving objects and occlusions utilizing the difference of the flow fields and depth structure generated by affine transformation and view synthesis, respectively. Secondly, we mitigate the effect of textureless regions on model optimization by measuring differences between features with more semantic and contextual information without adding networks. In addition, although the bidirectionality component is used in each sub-objective function, a pair of images are reasoned about only once, which helps reduce overhead. Extensive experiments and visual analysis demonstrate the effectiveness of the proposed method, which outperform existing state-of-the-art self-supervised methods under the same conditions and without introducing additional auxiliary information.

The prediction of protein structures from sequences is an important task for function prediction, drug design, and related biological processes understanding. Recent advances have proved the power of language models (LMs) in processing the protein sequence databases, which inherit the advantages of attention networks and capture useful information in learning representations for proteins. The past two years have witnessed remarkable success in tertiary protein structure prediction (PSP), including evolution-based and single-sequence-based PSP. It seems that instead of using energy-based models and sampling procedures, protein language model (pLM)-based pipelines have emerged as mainstream paradigms in PSP. Despite the fruitful progress, the PSP community needs a systematic and up-to-date survey to help bridge the gap between LMs in the natural language processing (NLP) and PSP domains and introduce their methodologies, advancements and practical applications. To this end, in this paper, we first introduce the similarities between protein and human languages that allow LMs extended to pLMs, and applied to protein databases. Then, we systematically review recent advances in LMs and pLMs from the perspectives of network architectures, pre-training strategies, applications, and commonly-used protein databases. Next, different types of methods for PSP are discussed, particularly how the pLM-based architectures function in the process of protein folding. Finally, we identify challenges faced by the PSP community and foresee promising research directions along with the advances of pLMs. This survey aims to be a hands-on guide for researchers to understand PSP methods, develop pLMs and tackle challenging problems in this field for practical purposes.

We present a unified hard-constraint framework for solving geometrically complex PDEs with neural networks, where the most commonly used Dirichlet, Neumann, and Robin boundary conditions (BCs) are considered. Specifically, we first introduce the "extra fields" from the mixed finite element method to reformulate the PDEs so as to equivalently transform the three types of BCs into linear forms. Based on the reformulation, we derive the general solutions of the BCs analytically, which are employed to construct an ansatz that automatically satisfies the BCs. With such a framework, we can train the neural networks without adding extra loss terms and thus efficiently handle geometrically complex PDEs, alleviating the unbalanced competition between the loss terms corresponding to the BCs and PDEs. We theoretically demonstrate that the "extra fields" can stabilize the training process. Experimental results on real-world geometrically complex PDEs showcase the effectiveness of our method compared with state-of-the-art baselines.

在离线增强学习中，加权回归是一种常见方法，可以确保学习的政策与行为策略保持接近并防止选择样本外动作。在这项工作中，我们表明，由于政策模型的分配表达有限，以前的方法可能仍会在培训期间选择看不见的动作，这会偏离其最初动机。为了解决这个问题，我们通过将学习的政策分解为两个部分：表达生成行为模型和动作评估模型，采用生成方法。关键见解是，这种去耦避免学习具有封闭形式表达式的明确参数化的策略模型。直接学习行为策略使我们能够利用生成建模的现有进步，例如基于扩散的方法，以建模各种行为。至于行动评估，我们将方法与样本中的计划技术相结合，以进一步避免选择样本外动作并提高计算效率。 D4RL数据集的实验结果表明，与最先进的离线RL方法相比，我们提出的方法具有竞争性或卓越的性能，尤其是在诸如Antmaze之类的复杂任务中。我们还经验证明，我们的方法可以从包含多个独特但类似成功策略的异质数据集中成功学习，而以前的单峰政策失败了。

域适应是神经机器翻译的重要挑战。但是，传统的微调解决方案需要多次额外的培训，并产生高昂的成本。在本文中，我们提出了一种非调节范式，通过基于及时的方法解决域的适应性。具体来说，我们构建了双语短语级数据库，并从中检索相关对作为输入句子的提示。通过利用检索到的短语级提示（REPP），我们有效地提高了翻译质量。实验表明，我们的方法改善了域特异性的机器翻译，可用于6.2 BLEU分数，并改善了在没有额外训练的情况下，精度为11.5％的翻译约束。

基于深度学习的方法，例如物理知识的神经网络（PINN）和DeepOnets已显示出解决PDE受约束优化（PDECO）问题的希望。但是，现有方法不足以处理对优化目标具有复杂或非线性依赖性的PDE约束。在本文中，我们提出了一个新颖的双层优化框架，以通过将目标和约束的优化解耦来解决挑战。对于内部循环优化，我们采用PINN仅解决PDE约束。对于外循环，我们通过基于隐式函数定理（IFT）使用Broyden的方法来设计一种新颖的方法，该方法对于近似高度级别而言是有效且准确的。我们进一步介绍了高度级计算的理论解释和误差分析。在多个大规模和非线性PDE约束优化问题上进行了广泛的实验表明，与强基础相比，我们的方法可实现最新的结果。

高速，高分辨率的立体视频（H2-STEREO）视频使我们能够在细粒度上感知动态3D内容。然而，对商品摄像机的收购H2-STEREO视频仍然具有挑战性。现有的空间超分辨率或时间框架插值方法分别提供了缺乏时间或空间细节的折衷解决方案。为了减轻这个问题，我们提出了一个双摄像头系统，其中一台相机捕获具有丰富空间细节的高空间分辨率低框架速率（HSR-LFR）视频，而另一个摄像头则捕获了低空间分辨率的高架框架-Rate（LSR-HFR）视频带有光滑的时间细节。然后，我们设计了一个学习的信息融合网络（LIFNET），该网络利用跨摄像机冗余，以增强两种相机视图，从而有效地重建H2-STEREO视频。即使在大型差异场景中，我们也利用一个差异网络将时空信息传输到视图上，基于该视图，我们建议使用差异引导的LSR-HFR视图基于差异引导的流量扭曲，并针对HSR-LFR视图进行互补的扭曲。提出了特征域中的多尺度融合方法，以最大程度地减少HSR-LFR视图中闭塞引起的翘曲幽灵和孔。 LIFNET使用YouTube收集的高质量立体视频数据集以端到端的方式进行训练。广泛的实验表明，对于合成数据和摄像头捕获的真实数据，我们的模型均优于现有的最新方法。消融研究探讨了各个方面，包括时空分辨率，摄像头基线，摄像头解理，长/短曝光和应用程序，以充分了解其对潜在应用的能力。

时间序列异常检测（TSAD）是一项重要的数据挖掘任务，在物联网时代，许多应用程序。近年来，已经提出了大量基于神经网络的方法，与传统方法相比，在解决各个领域中挑战的TSAD问题方面的性能要好得多。然而，这些深层TSAD方法通常依赖于没有被异常污染的干净训练数据集来学习基础动力学的“正常概况”。这项要求是不平凡的，因为实际上很难提供干净的数据集。此外，如果没有意识到其鲁棒性的意识，则盲目地应用具有潜在污染训练数据的深层TSAD方法可能会在检测阶段引起显着的性能降解。在这项工作中，为了应对这一重要挑战，我们首先使用受污染的培训数据研究常用的深层TSAD方法的鲁棒性，该方法在不保证无异常的训练数据时提供了应用这些方法的指南。此外，我们提出了一种模型不足的方法，该方法可以有效地改善具有潜在污染数据的主流深层TSAD模型的鲁棒性。实验结果表明，我们的方法可以始终防止或减轻广泛使用基准数据集上主流深层TSAD模型的性能下降。

图形神经网络（GNN）是具有无核数据的应用的有前途的方法。但是，具有数亿节点的大规模图上的培训GNN既是资源又是耗时的。与DNN不同，GNN通常具有更大的内存足迹，因此GPU内存能力和PCIE带宽是GNN培训中的主要资源瓶颈。为了解决此问题，我们提出分叉：一种图形量化方法，通过显着减少内存足迹和PCIE带宽要求来加速GNN训练，以便GNN可以充分利用GPU计算功能。我们的关键见解是，与DNN不同，GNN不太容易发生量化引起的输入特征的信息丢失。我们确定图形特征量化中的主要准确性影响因素，从理论上证明，分叉训练会收敛到网络，在该网络中，损失在未压缩网络的最佳损失的$ \ epsilon $之内。我们使用几种流行的GNN模型和数据集对分叉进行了广泛的评估，包括最大的公共图数据集MAG240M上的图形。结果表明，分叉达到30以上的压缩率，并在边际准确性损失的情况下提高了GNN训练速度200％-320％。特别是，分叉在一小时内仅使用四个GPU在MAG240M上的训练图来实现记录。