随着自我监督学习的快速发展（例如，对比度学习），在医学图像分析中广泛认识到具有大规模图像（即使没有注释）来训练更具概括的AI模型的重要性。但是，大规模收集大规模任务的未注释数据对于单个实验室来说可能具有挑战性。现有的在线资源（例如数字书籍，出版物和搜索引擎）为获取大型图像提供了新的资源。然而，在医疗保健中发布的图像（例如放射学和病理学）由大量的带有子图的复合图组成。为了提取和分离化合物形象为下游学习的可用单个图像，我们提出了一个简单的复合图分离（SIMCFS）框架，而无需使用传统所需的检测边界框注释，并具有新的损失函数和硬案例模拟。我们的技术贡献是四倍：（1）我们引入了一个基于模拟的培训框架，该框架最小化了对资源广泛的边界框注释的需求； （2）我们提出了一种新的侧损失，可针对复合人物分离进行优化； （3）我们提出了一种阶层内图像增强方法来模拟硬病例； （4）据我们所知，这是第一项评估利用复合图像分离的自我监督学习功效的研究。从结果来看，提出的SIMCF在ImageClef 2016复合人物分离数据库上实现了最先进的性能。使用大规模开采数字的预审预革的学习模型通过对比度学习算法提高了下游图像分类任务的准确性。 SIMCF的源代码可在https://github.com/hrlblab/imageseperation上公开获得。

由于物体的异质尺度，肾脏病理图像的全面语义分割具有挑战性。例如，在整个幻灯片图像（WSI）上，肾小球的横截面区域的距离可能比周围毛细管的64倍，这使得以相同尺度上的同一贴片对两个对象进行分割是不切实际的。为了解决这个缩放问题，先前的研究通常已经训练了多个分割网络，以匹配异质组织类型的最佳像素分辨率。这种多网络解决方案是资源密集型的，无法对组织类型之间的空间关系进行建模。在本文中，我们提出了Omni-Seg+网络，这是一种通过单个神经网络实现多对象（六种组织类型）和多尺度（5倍至40倍尺度）的多尺度（5倍至40倍尺度）的动态神经网络。本文的贡献是三个方面的：（1）提出了一种新型的量表感知控制器，以将动态神经网络从单尺度到多尺度推广； （2）引入了伪标签的半监督一致性正规化，以建模未经注释的组织类型的尺度相关性成单个端到端的学习范式； （3）直接将在人类肾脏图像训练的模型中直接应用于小鼠肾脏图像，而无需再培训，就可以证明高尺度感知的概括。通过从三种不同分辨率下从六种组织类型中学习的约150,000个人类病理图像斑块，我们的方法根据人类的视觉评估和图像词的评估（即空间转录组学）获得了卓越的分割性能。官方实施可在https://github.com/ddrrnn123/omni-seg上获得。

整合跨部门多模式数据（例如，放射学，病理学，基因组和临床数据）无处不在，在脑癌诊断和存活预测中无处不在。迄今为止，这种整合通常是由人类医师（以及专家小组）进行的，可以是主观的和半定量的。然而，多模式深度学习的最新进展已为利用这种过程以更加客观和定量的方式打开了一扇门。不幸的是，先前在脑癌生存预测上使用四种模式的艺术受到“完整模式”设置的限制（即，所有可用方式）。因此，关于如何有效预测脑癌生存的问题仍然存在开放性问题，从放射学，病理学，基因组和人口统计学数据中（例如，可能无法为患者收集一种或多种方式）。例如，我们是否应该同时使用完整和不完整的数据，更重要的是，如何使用这些数据？为了回答前面的问题，我们将跨部门多模式数据的多模式学习推广到缺失的数据设置。我们的贡献是三个方面：1）我们引入了最佳的多模式学习，其中缺少数据（MMD）管道具有优化的硬件消耗和计算效率； 2）我们将有关放射学，病理，基因组和人口统计学数据的多模式学习扩展到缺失的数据情景； 3）收集了一个大规模的公共数据集（有962名患者），以系统地评估胶质瘤肿瘤存活预测。所提出的方法将生存预测的C索引从0.7624提高到0.8053。

关于Giga-Pixel病理学图像的计算机辅助定量分析提供了精密药物的新大道。该创新主要集中在癌症病理学（即，肿瘤分割和表征）上。在非癌症病理学中，可以要求学习算法同时检查更全面的组织类型，作为多标签设置。现有技术通常需要训练多个分段网络，以匹配非均相组织类型的域特异性知识（例如，肾小球簇，肾小球单元，近端管，远端管，梗塞和动脉）。在本文中，我们提出了一种动态单分割网络（OMNI-SEG），该网络（OMNI-SEG）学习使用部分标记的图像（即，仅针对每个训练图像标记一个组织类型）进行多种组织类型进行肾脏病理学。通过从六种组织类型学习〜150,000的Patch-Wise病理图像，与先前的多网络和多头设计相比，所提出的Omni-SEG网络实现了卓越的分割精度和更少的资源消耗。在测试阶段，所提出的方法仅使用“部分标记”训练图像获得“完全标记的”组织分割结果。源代码可在https://github.com/ddrrnn123/omni-seg中获得。

Unsupervised person re-identification (ReID) aims at learning discriminative identity features for person retrieval without any annotations. Recent advances accomplish this task by leveraging clustering-based pseudo labels, but these pseudo labels are inevitably noisy which deteriorate model performance. In this paper, we propose a Neighbour Consistency guided Pseudo Label Refinement (NCPLR) framework, which can be regarded as a transductive form of label propagation under the assumption that the prediction of each example should be similar to its nearest neighbours'. Specifically, the refined label for each training instance can be obtained by the original clustering result and a weighted ensemble of its neighbours' predictions, with weights determined according to their similarities in the feature space. In addition, we consider the clustering-based unsupervised person ReID as a label-noise learning problem. Then, we proposed an explicit neighbour consistency regularization to reduce model susceptibility to over-fitting while improving the training stability. The NCPLR method is simple yet effective, and can be seamlessly integrated into existing clustering-based unsupervised algorithms. Extensive experimental results on five ReID datasets demonstrate the effectiveness of the proposed method, and showing superior performance to state-of-the-art methods by a large margin.

Dataset distillation has emerged as a prominent technique to improve data efficiency when training machine learning models. It encapsulates the knowledge from a large dataset into a smaller synthetic dataset. A model trained on this smaller distilled dataset can attain comparable performance to a model trained on the original training dataset. However, the existing dataset distillation techniques mainly aim at achieving the best trade-off between resource usage efficiency and model utility. The security risks stemming from them have not been explored. This study performs the first backdoor attack against the models trained on the data distilled by dataset distillation models in the image domain. Concretely, we inject triggers into the synthetic data during the distillation procedure rather than during the model training stage, where all previous attacks are performed. We propose two types of backdoor attacks, namely NAIVEATTACK and DOORPING. NAIVEATTACK simply adds triggers to the raw data at the initial distillation phase, while DOORPING iteratively updates the triggers during the entire distillation procedure. We conduct extensive evaluations on multiple datasets, architectures, and dataset distillation techniques. Empirical evaluation shows that NAIVEATTACK achieves decent attack success rate (ASR) scores in some cases, while DOORPING reaches higher ASR scores (close to 1.0) in all cases. Furthermore, we conduct a comprehensive ablation study to analyze the factors that may affect the attack performance. Finally, we evaluate multiple defense mechanisms against our backdoor attacks and show that our attacks can practically circumvent these defense mechanisms.

Blind image quality assessment (BIQA) remains challenging due to the diversity of distortion and image content variation, which complicate the distortion patterns crossing different scales and aggravate the difficulty of the regression problem for BIQA. However, existing BIQA methods often fail to consider multi-scale distortion patterns and image content, and little research has been done on learning strategies to make the regression model produce better performance. In this paper, we propose a simple yet effective Progressive Multi-Task Image Quality Assessment (PMT-IQA) model, which contains a multi-scale feature extraction module (MS) and a progressive multi-task learning module (PMT), to help the model learn complex distortion patterns and better optimize the regression issue to align with the law of human learning process from easy to hard. To verify the effectiveness of the proposed PMT-IQA model, we conduct experiments on four widely used public datasets, and the experimental results indicate that the performance of PMT-IQA is superior to the comparison approaches, and both MS and PMT modules improve the model's performance.

The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.

Given the increasingly intricate forms of partial differential equations (PDEs) in physics and related fields, computationally solving PDEs without analytic solutions inevitably suffers from the trade-off between accuracy and efficiency. Recent advances in neural operators, a kind of mesh-independent neural-network-based PDE solvers, have suggested the dawn of overcoming this challenge. In this emerging direction, Koopman neural operator (KNO) is a representative demonstration and outperforms other state-of-the-art alternatives in terms of accuracy and efficiency. Here we present KoopmanLab, a self-contained and user-friendly PyTorch module of the Koopman neural operator family for solving partial differential equations. Beyond the original version of KNO, we develop multiple new variants of KNO based on different neural network architectures to improve the general applicability of our module. These variants are validated by mesh-independent and long-term prediction experiments implemented on representative PDEs (e.g., the Navier-Stokes equation and the Bateman-Burgers equation) and ERA5 (i.e., one of the largest high-resolution data sets of global-scale climate fields). These demonstrations suggest the potential of KoopmanLab to be considered in diverse applications of partial differential equations.

A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.