目的：目的是将先前验证的深度学习算法应用于新的甲状腺结节超声图像数据集，并将其性能与放射科医生进行比较。方法：先前的研究提出了一种能够检测甲状腺结节，然后使用两个超声图像进行恶性分类的算法。从1278个结节训练了多任务深度卷积神经网络，最初用99个单独的结节进行了测试。结果与放射科医生相当。与培训案例相比，使用来自不同制造商和产品类型的超声计算机成像的378个结节进一步测试了该算法。要求四名经验丰富的放射科医生评估结节，以与深度学习进行比较。结果：用参数，二维估计计算了深度学习算法和四个放射科医生的曲线（AUC）面积。对于深度学习算法，AUC为0.70（95％CI：0.64-0.75）。放射科医生的AUC为0.66（95％CI：0.61-0.71），0.67（95％CI：0.62-0.73），0.68（95％CI：0.63-0.73）和0.66（95％CI：95％CI：0.61-0.71）。结论：在新的测试数据集中，深度学习算法与所有四个放射科医生都达到了类似的性能。

使用Kellgren-Lawence分级系统在放射线照片中评估放射性骨关节炎的严重程度评估放射科医生的表现，是放射学家的表现。根据Kellgren-Lawence分级系统，开发一种自动化的基于深度学习的算法，该算法使用膝盖X光片的后侧（PA）和侧面（LAT）视图来评估膝关节骨关节炎的严重程度。我们使用了来自多中心骨关节炎研究的2802名患者的9739例检查的数据集（大多数）。该数据集分为2040名患者的训练集，259例患者的验证和503例患者的测试组。一种新型的基于深度学习的方法用于评估膝关节OA分为两个步骤：（1）图像中膝关节的定位，（2）根据KL分级系统进行分类。我们的方法同时使用PA和LAT视图作为模型的输入。将算法生成的分数与整个测试集的最多数据集中提供的等级以及我们机构中5位放射科医生提供的成绩进行了比较。与大多数数据集中提供的评分相比，该模型在整个测试集上获得了71.90％的多级准确性。该组的二次加权KAPPA系数为0.9066。我们机构的所有放射科医生对研究的平均二次加权Kappa为0.748。我们机构的算法和放射科医生之间的平均二次加权Kappa为0.769。所提出的模型表明，KL分类与MSK放射科医生的等效性，但显然可重复性。我们的模型还与我们机构的放射科医生同意与放射科医生相同的程度。该算法可用于提供膝关节炎严重程度的可重复评估。

膝关节X射线上的膝盖骨关节炎（KOA）的评估是使用总膝关节置换术的中心标准。但是，该评估遭受了不精确的标准，并且读取器间的可变性非常高。对KOA严重性的算法，自动评估可以通过提高其使用的适当性来改善膝盖替代程序的总体结果。我们提出了一种基于深度学习的新型五步算法，以自动从X光片后验（PA）视图对KOA进行评级：（1）图像预处理（2）使用Yolo V3-tiny模型，图像在图像中定位膝关节， （3）使用基于卷积神经网络的分类器对骨关节炎的严重程度进行初步评估，（4）关节分割和关节空间狭窄（JSN）的计算（JSN）和（5），JSN和最初的结合评估确定最终的凯尔格伦法律（KL）得分。此外，通过显示用于进行评估的分割面具，我们的算法与典型的“黑匣子”深度学习分类器相比表现出更高的透明度。我们使用我们机构的两个公共数据集和一个数据集进行了全面的评估，并表明我们的算法达到了最先进的性能。此外，我们还从机构中的多个放射科医生那里收集了评分，并表明我们的算法在放射科医生级别进行。该软件已在https://github.com/maciejmazurowowski/osteoarthitis-classification上公开提供。

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.

Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.