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.

深度学习方法在图像染色中优于传统方法。为了生成上下文纹理，研究人员仍在努力改进现有方法，并提出可以提取，传播和重建类似于地面真实区域的特征的模型。此外，更深层的缺乏高质量的特征传递机制有助于对所产生的染色区域有助于持久的像差。为了解决这些限制，我们提出了V-Linknet跨空间学习策略网络。为了改善语境化功能的学习，我们设计了一种使用两个编码器的损失模型。此外，我们提出了递归残留过渡层（RSTL）。 RSTL提取高电平语义信息并将其传播为下层。最后，我们将在与不同面具的同一面孔和不同面部面上的相同面上进行了比较的措施。为了提高图像修复再现性，我们提出了一种标准协议来克服各种掩模和图像的偏差。我们使用实验方法调查V-LinkNet组件。当使用标准协议时，在Celeba-HQ上评估时，我们的结果超越了现有技术。此外，我们的模型可以在Paris Street View上评估时概括良好，以及具有标准协议的Parume2数据集。

本文提供了在过去十年中开发糖尿病足溃疡数据集的概念基础和程序，有一个时间线来证明进步。我们对脚踏照片的数据捕获方法进行了调查，概述了开发私立和公共数据集的研究，相关的计算机视觉任务（检测，分割和分类），糖尿病足溃疡挑战和未来发展的发展方向数据集。我们通过国家和年度报告数据集用户的分发。我们的目标是分享我们与DataSet开发的良好做法遇到的技术挑战，并为其他研究人员提供参与该域中的数据共享的动机。

糖尿病足溃疡分类系统使用伤口感染（伤口内的细菌）和缺血（限制血供给）作为重要的临床指标治疗和预测伤口愈合。研究使用自动化计算机化方法在糖尿病足伤中使用自动化计算机化方法的使用和缺血的使用是有限的，这是有限的，因为存在的公开可用数据集和严重数据不平衡存在。糖尿病脚溃疡挑战2021提供了一种具有更大量数据集的参与者，其总共包括15,683只糖尿病足溃疡贴剂，用于训练5,734，用于测试，额外的3,994个未标记的贴片，以促进半监督和弱的发展 - 监督深度学习技巧。本文提供了对糖尿病足溃疡攻击2021中使用的方法的评估，并总结了从每个网络获得的结果。最佳性能的网络是前3种型号的结果的集合，宏观平均F1分数为0.6307。

Unsupervised domain adaptation (UDA) via deep learning has attracted appealing attention for tackling domain-shift problems caused by distribution discrepancy across different domains. Existing UDA approaches highly depend on the accessibility of source domain data, which is usually limited in practical scenarios due to privacy protection, data storage and transmission cost, and computation burden. To tackle this issue, many source-free unsupervised domain adaptation (SFUDA) methods have been proposed recently, which perform knowledge transfer from a pre-trained source model to unlabeled target domain with source data inaccessible. A comprehensive review of these works on SFUDA is of great significance. In this paper, we provide a timely and systematic literature review of existing SFUDA approaches from a technical perspective. Specifically, we categorize current SFUDA studies into two groups, i.e., white-box SFUDA and black-box SFUDA, and further divide them into finer subcategories based on different learning strategies they use. We also investigate the challenges of methods in each subcategory, discuss the advantages/disadvantages of white-box and black-box SFUDA methods, conclude the commonly used benchmark datasets, and summarize the popular techniques for improved generalizability of models learned without using source data. We finally discuss several promising future directions in this field.

Model counting is a fundamental problem which has been influential in many applications, from artificial intelligence to formal verification. Due to the intrinsic hardness of model counting, approximate techniques have been developed to solve real-world instances of model counting. This paper designs a new anytime approach called PartialKC for approximate model counting. The idea is a form of partial knowledge compilation to provide an unbiased estimate of the model count which can converge to the exact count. Our empirical analysis demonstrates that PartialKC achieves significant scalability and accuracy over prior state-of-the-art approximate counters, including satss and STS. Interestingly, the empirical results show that PartialKC reaches convergence for many instances and therefore provides exact model counting performance comparable to state-of-the-art exact counters.

A central problem in computational biophysics is protein structure prediction, i.e., finding the optimal folding of a given amino acid sequence. This problem has been studied in a classical abstract model, the HP model, where the protein is modeled as a sequence of H (hydrophobic) and P (polar) amino acids on a lattice. The objective is to find conformations maximizing H-H contacts. It is known that even in this reduced setting, the problem is intractable (NP-hard). In this work, we apply deep reinforcement learning (DRL) to the two-dimensional HP model. We can obtain the conformations of best known energies for benchmark HP sequences with lengths from 20 to 50. Our DRL is based on a deep Q-network (DQN). We find that a DQN based on long short-term memory (LSTM) architecture greatly enhances the RL learning ability and significantly improves the search process. DRL can sample the state space efficiently, without the need of manual heuristics. Experimentally we show that it can find multiple distinct best-known solutions per trial. This study demonstrates the effectiveness of deep reinforcement learning in the HP model for protein folding.

This paper proposes Mutual Information Regularized Assignment (MIRA), a pseudo-labeling algorithm for unsupervised representation learning inspired by information maximization. We formulate online pseudo-labeling as an optimization problem to find pseudo-labels that maximize the mutual information between the label and data while being close to a given model probability. We derive a fixed-point iteration method and prove its convergence to the optimal solution. In contrast to baselines, MIRA combined with pseudo-label prediction enables a simple yet effective clustering-based representation learning without incorporating extra training techniques or artificial constraints such as sampling strategy, equipartition constraints, etc. With relatively small training epochs, representation learned by MIRA achieves state-of-the-art performance on various downstream tasks, including the linear/k-NN evaluation and transfer learning. Especially, with only 400 epochs, our method applied to ImageNet dataset with ResNet-50 architecture achieves 75.6% linear evaluation accuracy.

在带有频划分双链体（FDD）的常规多用户多用户多输入多输出（MU-MIMO）系统中，尽管高度耦合，但已单独设计了通道采集和预编码器优化过程。本文研究了下行链路MU-MIMO系统的端到端设计，其中包括试点序列，有限的反馈和预编码。为了解决这个问题，我们提出了一个新颖的深度学习（DL）框架，该框架共同优化了用户的反馈信息生成和基础站（BS）的预编码器设计。 MU-MIMO系统中的每个过程都被智能设计的多个深神经网络（DNN）单元所取代。在BS上，神经网络生成试验序列，并帮助用户获得准确的频道状态信息。在每个用户中，频道反馈操作是由单个用户DNN以分布方式进行的。然后，另一个BS DNN从用户那里收集反馈信息，并确定MIMO预编码矩阵。提出了联合培训算法以端到端的方式优化所有DNN单元。此外，还提出了一种可以避免针对可扩展设计的不同网络大小进行重新训练的培训策略。数值结果证明了与经典优化技术和其他常规DNN方案相比，提出的DL框架的有效性。

用于皮肤病变分析的计算机辅助诊断系统（CAD）系统是一个新兴的研究领域，有可能减轻皮肤癌筛查的负担和成本。研究人员最近表示，对开发此类CAD系统的兴趣日益增加，目的是向皮肤科医生提供用户友好的工具，以减少手动检查提出的挑战。本文的目的是提供对2011年至2020年之间发表的尖端CAD技术的完整文献综述。使用系统评价和荟萃分析的首选报告项目（PRISMA）方法用于确定总共365个出版物，221用于皮肤病变细分，144用于皮肤病变分类。这些文章以多种不同的方式进行分析和汇总，以便我们可以贡献有关CAD系统发展方法的重要信息。这些方式包括：相关和基本的定义和理论，输入数据（数据集利用，预处理，增强和解决不平衡问题），方法配置（技术，体系结构，模块框架和损失），培训策略（超级表格设置）以及评估（评估）标准（指标）。我们还打算研究各种增强性能的方法，包括合奏和后处理。此外，在这项调查中，我们强调了使用最小数据集评估皮肤病变细分和分类系统的主要问题，以及对这些困境的潜在解决方案。总之，讨论了启发性发现，建议和趋势，目的是为了在关注的相关领域进行未来的研究监视。可以预见的是，它将在开发自动化和健壮的CAD系统进行皮肤病变分析的过程中指导从初学者到专家的各个级别的研究人员。