尽管最近的分布（OOD）检测，异常检测和不确定性估计任务的最新进展，但并不存在任务不合时宜的和事后方法。为了解决此限制，我们设计了一种基于聚类的新型结合方法，称为任务不可知和事后看不见的分布检测（TAPUDD），该方法利用了从对特定任务进行训练的模型中提取的功能。它明确地包括Tap-Mahalanobis，该曲线簇起训练数据集的特征，并确定了所有群集的测试样品的最小Mahalanobis距离。此外，我们提出了一个结合模块，该模块汇总了对不同数量簇的迭代TAP-MAHALANOBIS的计算，以提供可靠，有效的群集计算。通过对合成和现实世界数据集进行的广泛实验，我们观察到我们的方法可以在各种任务中有效地检测出看不见的样本，并与现有基线进行更好的或与现有基线相比。为此，我们消除了确定簇数量的最佳价值的必要性，并证明我们的方法对于大规模分类任务更可行。

联合学习（FL）是一个活跃的研究领域。采用FL的最合适区域之一是医疗领域，必须尊重患者隐私。但是，先前的研究并未完全考虑谁最有可能在医疗领域使用FL。渴望采用FL的不是医院，而是想要开发具有真实患者记录的机器学习模型的服务提供商。此外，服务提供商希望以最低成本的可能性来最大程度地提高模型的性能。在这项工作中，我们提出了FL方法的经验基准，考虑了三个现实世界数据集的性能和货币成本：电子健康记录，皮肤癌图像和心电图数据集。我们还建议使用近端正则化的联合学习，除了局部归一化（FEDPXN），该学习使用FEDPROX和FEDBN的简单组合优于所有其他FL算法，而仅消耗比最高效率的方法稍大一些。

基于变压器的模型已在各个领域（例如自然语言处理和计算机视觉）中广泛使用并实现了最先进的性能。最近的作品表明，变压器也可以推广到图形结构化数据。然而，由于技术挑战，诸如节点数量和非本地聚集的技术挑战之类的技术挑战，因此成功限于小规模图，这通常会导致对常规图神经网络的概括性能。在本文中，为了解决这些问题，我们提出了可变形的图形变压器（DGT），以动态采样的键和值对进行稀疏注意。具体而言，我们的框架首先构建具有各种标准的多个节点序列，以考虑结构和语义接近。然后，将稀疏的注意力应用于节点序列，以减少计算成本，以学习节点表示。我们还设计简单有效的位置编码，以捕获节点之间的结构相似性和距离。实验表明，我们的新型图形变压器始终胜过现有的基于变压器的模型，并且与8个图形基准数据集（包括大型图形）的最新模型相比，与最新的模型相比表现出竞争性能。

图形神经网络（GNN）已被广泛应用于各种领域，以通过图形结构数据学习。在各种任务（例如节点分类和图形分类）中，他们对传统启发式方法显示了显着改进。但是，由于GNN严重依赖于平滑的节点特征而不是图形结构，因此在链接预测中，它们通常比简单的启发式方法表现出差的性能，例如，结构信息（例如，重叠的社区，学位和最短路径）至关重要。为了解决这一限制，我们建议邻里重叠感知的图形神经网络（NEO-GNNS），这些神经网络（NEO-GNNS）从邻接矩阵中学习有用的结构特征，并估算了重叠的邻域以进行链接预测。我们的Neo-Gnns概括了基于社区重叠的启发式方法，并处理重叠的多跳社区。我们在开放图基准数据集（OGB）上进行的广泛实验表明，NEO-GNNS始终在链接预测中实现最新性能。我们的代码可在https://github.com/seongjunyun/neo_gnns上公开获取。

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.

Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.