深度神经网络(DNNS)在训练过程中容易受到后门攻击的影响。该模型以这种方式损坏正常起作用,但是当输入中的某些模式触发时,会产生预定义的目标标签。现有防御通常依赖于通用后门设置的假设,其中有毒样品共享相同的均匀扳机。但是,最近的高级后门攻击表明,这种假设在动态后门中不再有效,在动态后门中,触发者因输入而异,从而击败了现有的防御。在这项工作中,我们提出了一种新颖的技术BEATRIX(通过革兰氏矩阵检测)。 BEATRIX利用革兰氏矩阵不仅捕获特征相关性,还可以捕获表示形式的适当高阶信息。通过从正常样本的激活模式中学习类条件统计,BEATRIX可以通过捕获激活模式中的异常来识别中毒样品。为了进一步提高识别目标标签的性能,BEATRIX利用基于内核的测试,而无需对表示分布进行任何先前的假设。我们通过与最先进的防御技术进行了广泛的评估和比较来证明我们的方法的有效性。实验结果表明,我们的方法在检测动态后门时达到了91.1%的F1得分,而最新技术只能达到36.9%。
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随着视频数量的越来越多,对技术的需求很大,可以帮助人们迅速导航到他们感兴趣的视频片段。但是,当前的视频理解主要理解主要是视频内容摘要,而几乎没有努力,而对探索视频的结构。受文本轮廓生成的启发,我们介绍了一项新颖的视频理解任务,即视频大纲生成(VOG)。该任务定义为包含两个子任务:(1)首先根据内容结构对视频进行分割,然后(2)为每个段生成一个标题。要学习和评估VOG,我们注释了一个10K+数据集,称为Duvog。具体来说,我们使用OCR工具来识别视频的字幕。然后,要求注释者将字幕分为章节,并将每个章节分为标题。在视频中,突出显示的文本往往是标题,因为它更有可能引起人们的注意。因此,我们提出了一个视觉字幕功能增强的视频大纲生成模型(VSENET),该模型将文本字幕及其视觉字体大小和位置作为输入。我们将VOG任务视为一个序列标记问题,该问题提取了跨标题的位置,然后将其重写以形成最终大纲。此外,基于视频概述和文本概述之间的相似性,我们使用大量文章带有章节标题来预先我们的模型。 Duvog上的实验表明,我们的模型在很大程度上胜过其他基线方法,对于视频分割水平达到了77.1的F1得分,对于标题生成级别的Rouge-L_F0.5的85.0。
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每时每刻都生产出许多不同质量的物品,因此将这些数据筛选为质量文章并将其投入到社交媒体上是一项非常紧迫的任务。值得注意的是,高质量的文章具有许多特征,例如相关性,文本质量,直接,多面,背景,新颖性和情感。因此,纯粹使用文章的内容来识别其质量是不够的。因此,我们计划使用外部知识互动来完善性能,并根据百度百科全书提出知识图增强文章质量标识数据集(KGEA)。我们通过7个维度量化了这些文章,并使用文章和百度百科全书之间实体的同时出现,以构建每篇文章的知识图。我们还比较了一些文本分类基线,发现外部知识可以将文章引导到与图神经网络更具竞争力的分类。
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Video classification systems are vulnerable to adversarial attacks, which can create severe security problems in video verification. Current black-box attacks need a large number of queries to succeed, resulting in high computational overhead in the process of attack. On the other hand, attacks with restricted perturbations are ineffective against defenses such as denoising or adversarial training. In this paper, we focus on unrestricted perturbations and propose StyleFool, a black-box video adversarial attack via style transfer to fool the video classification system. StyleFool first utilizes color theme proximity to select the best style image, which helps avoid unnatural details in the stylized videos. Meanwhile, the target class confidence is additionally considered in targeted attacks to influence the output distribution of the classifier by moving the stylized video closer to or even across the decision boundary. A gradient-free method is then employed to further optimize the adversarial perturbations. We carry out extensive experiments to evaluate StyleFool on two standard datasets, UCF-101 and HMDB-51. The experimental results demonstrate that StyleFool outperforms the state-of-the-art adversarial attacks in terms of both the number of queries and the robustness against existing defenses. Moreover, 50% of the stylized videos in untargeted attacks do not need any query since they can already fool the video classification model. Furthermore, we evaluate the indistinguishability through a user study to show that the adversarial samples of StyleFool look imperceptible to human eyes, despite unrestricted perturbations.
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A recent trojan attack on deep neural network (DNN) models is one insidious variant of data poisoning attacks. Trojan attacks exploit an effective backdoor created in a DNN model by leveraging the difficulty in interpretability of the learned model to misclassify any inputs signed with the attacker's chosen trojan trigger. Since the trojan trigger is a secret guarded and exploited by the attacker, detecting such trojan inputs is a challenge, especially at run-time when models are in active operation. This work builds STRong Intentional Perturbation (STRIP) based run-time trojan attack detection system and focuses on vision system. We intentionally perturb the incoming input, for instance by superimposing various image patterns, and observe the randomness of predicted classes for perturbed inputs from a given deployed model-malicious or benign. A low entropy in predicted classes violates the input-dependence property of a benign model and implies the presence of a malicious input-a characteristic of a trojaned input. The high efficacy of our method is validated through case studies on three popular and contrasting datasets: MNIST, CIFAR10 and GTSRB. We achieve an overall false acceptance rate (FAR) of less than 1%, given a preset false rejection rate (FRR) of 1%, for different types of triggers. Using CIFAR10 and GTSRB, we have empirically achieved result of 0% for both FRR and FAR. We have also evaluated STRIP robustness against a number of trojan attack variants and adaptive attacks.
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联合学习(FL)是一项广泛采用的分布式学习范例,在实践中,打算在利用所有参与者的整个数据集进行培训的同时保护用户的数据隐私。在FL中,多种型号在用户身上独立培训,集中聚合以在迭代过程中更新全局模型。虽然这种方法在保护隐私方面是优异的,但FL仍然遭受攻击或拜占庭故障等质量问题。最近的一些尝试已经解决了对FL的强大聚集技术的这种质量挑战。然而,最先进的(SOTA)强大的技术的有效性尚不清楚并缺乏全面的研究。因此,为了更好地了解这些SOTA流域的当前质量状态和挑战在存在攻击和故障的情况下,我们进行了大规模的实证研究,以研究SOTA FL的质量,从多个攻击角度,模拟故障(通过突变运算符)和聚合(防御)方法。特别是,我们对两个通用图像数据集和一个现实世界联邦医学图像数据集进行了研究。我们还系统地调查了攻击用户和独立和相同分布的(IID)因子,每个数据集的攻击/故障的分布对鲁棒性结果的影响。经过496个配置进行大规模分析后,我们发现每个用户的大多数突变者对最终模型具有可忽略不计的影响。此外,选择最强大的FL聚合器取决于攻击和数据集。最后,我们说明了可以实现几乎在所有攻击和配置上的任何单个聚合器以及具有简单集合模型的所有攻击和配置的常用解决方案的通用解决方案。
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In this paper, we propose a robust 3D detector, named Cross Modal Transformer (CMT), for end-to-end 3D multi-modal detection. Without explicit view transformation, CMT takes the image and point clouds tokens as inputs and directly outputs accurate 3D bounding boxes. The spatial alignment of multi-modal tokens is performed implicitly, by encoding the 3D points into multi-modal features. The core design of CMT is quite simple while its performance is impressive. CMT obtains 73.0% NDS on nuScenes benchmark. Moreover, CMT has a strong robustness even if the LiDAR is missing. Code will be released at https://github.com/junjie18/CMT.
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Knowledge graphs (KG) have served as the key component of various natural language processing applications. Commonsense knowledge graphs (CKG) are a special type of KG, where entities and relations are composed of free-form text. However, previous works in KG completion and CKG completion suffer from long-tail relations and newly-added relations which do not have many know triples for training. In light of this, few-shot KG completion (FKGC), which requires the strengths of graph representation learning and few-shot learning, has been proposed to challenge the problem of limited annotated data. In this paper, we comprehensively survey previous attempts on such tasks in the form of a series of methods and applications. Specifically, we first introduce FKGC challenges, commonly used KGs, and CKGs. Then we systematically categorize and summarize existing works in terms of the type of KGs and the methods. Finally, we present applications of FKGC models on prediction tasks in different areas and share our thoughts on future research directions of FKGC.
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Few Shot Instance Segmentation (FSIS) requires models to detect and segment novel classes with limited several support examples. In this work, we explore a simple yet unified solution for FSIS as well as its incremental variants, and introduce a new framework named Reference Twice (RefT) to fully explore the relationship between support/query features based on a Transformer-like framework. Our key insights are two folds: Firstly, with the aid of support masks, we can generate dynamic class centers more appropriately to re-weight query features. Secondly, we find that support object queries have already encoded key factors after base training. In this way, the query features can be enhanced twice from two aspects, i.e., feature-level and instance-level. In particular, we firstly design a mask-based dynamic weighting module to enhance support features and then propose to link object queries for better calibration via cross-attention. After the above steps, the novel classes can be improved significantly over our strong baseline. Additionally, our new framework can be easily extended to incremental FSIS with minor modification. When benchmarking results on the COCO dataset for FSIS, gFSIS, and iFSIS settings, our method achieves a competitive performance compared to existing approaches across different shots, e.g., we boost nAP by noticeable +8.2/+9.4 over the current state-of-the-art FSIS method for 10/30-shot. We further demonstrate the superiority of our approach on Few Shot Object Detection. Code and model will be available.
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Graph Neural Networks (GNNs) have shown satisfying performance on various graph learning tasks. To achieve better fitting capability, most GNNs are with a large number of parameters, which makes these GNNs computationally expensive. Therefore, it is difficult to deploy them onto edge devices with scarce computational resources, e.g., mobile phones and wearable smart devices. Knowledge Distillation (KD) is a common solution to compress GNNs, where a light-weighted model (i.e., the student model) is encouraged to mimic the behavior of a computationally expensive GNN (i.e., the teacher GNN model). Nevertheless, most existing GNN-based KD methods lack fairness consideration. As a consequence, the student model usually inherits and even exaggerates the bias from the teacher GNN. To handle such a problem, we take initial steps towards fair knowledge distillation for GNNs. Specifically, we first formulate a novel problem of fair knowledge distillation for GNN-based teacher-student frameworks. Then we propose a principled framework named RELIANT to mitigate the bias exhibited by the student model. Notably, the design of RELIANT is decoupled from any specific teacher and student model structures, and thus can be easily adapted to various GNN-based KD frameworks. We perform extensive experiments on multiple real-world datasets, which corroborates that RELIANT achieves less biased GNN knowledge distillation while maintaining high prediction utility.
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