图形神经网络(GNNS)在各种现实世界应用中取得了有希望的性能。然而,最近的研究表明,GNN易受对抗性发作的影响。在本文中,我们研究了关于图表 - 图 - 图注射攻击(GIA)的最近引入的现实攻击情景。在GIA场景中,对手无法修改输入图的现有链路结构和节点属性,而是通过将逆势节点注入到它中来执行攻击。我们对GIA环境下GNN的拓扑脆弱性分析,基于该拓扑结构,我们提出了用于有效注射攻击的拓扑缺陷图注射攻击(TDGIA)。 TDGIA首先介绍了拓扑有缺陷的边缘选择策略,可以选择与注入的原始节点连接。然后,它设计平滑功能优化目标,以生成注入节点的功能。大规模数据集的广泛实验表明,TDGIA可以一致而明显优于攻击数十个防御GNN模型中的各种攻击基线。值得注意的是,来自TDGIA的目标GNNS上的性能下降比KDD-CUP 2020上的数百个提交所带来的最佳攻击解决方案所带来的损坏多于两倍。
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同态加密(HE),允许对加密数据(Ciphertext)进行计算,而无需首先解密,因此可以实现对云中隐私性的应用程序的安全性缓慢的卷积神经网络(CNN)推断。为了减少推理潜伏期,一种方法是将多个消息打包到单个密文中,以减少密文的数量并支持同型多态多重蓄能(HMA)操作的大量并行性。尽管HECNN的推断速度更快,但主流包装方案密集的包装(密度)和卷积包装(Convpack)仍将昂贵的旋转开销引入了昂贵的旋转开销,这延长了HECNN的推断潜伏期,以实现更深和更广泛的CNN体​​系结构。在本文中,我们提出了一种名为FFCONV的低级分解方法,该方法专门用于有效的密文填料,用于减少旋转台面和HMA操作。 FFCONV近似于低级分解卷积的A D X D卷积层,其中D X D低率卷积具有较少的通道,然后是1 x 1卷积以恢复通道。 D X D低级别卷积带有密度,导致旋转操作显着降低,而1 x 1卷积的旋转开销接近零。据我们所知,FFCONV是能够同时减少densepack和Convpack产生的旋转头顶的第一项工作,而无需将其他特殊块引入HECNN推理管道。与先前的Art Lola和Falcon相比,我们的方法分别将推理潜伏期降低了88%和21%,其精度在MNIST和CIFAR-10上具有可比的精度。
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Autonomous vehicles must often contend with conflicting planning requirements, e.g., safety and comfort could be at odds with each other if avoiding a collision calls for slamming the brakes. To resolve such conflicts, assigning importance ranking to rules (i.e., imposing a rule hierarchy) has been proposed, which, in turn, induces rankings on trajectories based on the importance of the rules they satisfy. On one hand, imposing rule hierarchies can enhance interpretability, but introduce combinatorial complexity to planning; while on the other hand, differentiable reward structures can be leveraged by modern gradient-based optimization tools, but are less interpretable and unintuitive to tune. In this paper, we present an approach to equivalently express rule hierarchies as differentiable reward structures amenable to modern gradient-based optimizers, thereby, achieving the best of both worlds. We achieve this by formulating rank-preserving reward functions that are monotonic in the rank of the trajectories induced by the rule hierarchy; i.e., higher ranked trajectories receive higher reward. Equipped with a rule hierarchy and its corresponding rank-preserving reward function, we develop a two-stage planner that can efficiently resolve conflicting planning requirements. We demonstrate that our approach can generate motion plans in ~7-10 Hz for various challenging road navigation and intersection negotiation scenarios.
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Multi-modal image-text models such as CLIP and LiT have demonstrated impressive performance on image classification benchmarks and their zero-shot generalization ability is particularly exciting. While the top-5 zero-shot accuracies of these models are very high, the top-1 accuracies are much lower (over 25% gap in some cases). We investigate the reasons for this performance gap and find that many of the failure cases are caused by ambiguity in the text prompts. First, we develop a simple and efficient zero-shot post-hoc method to identify images whose top-1 prediction is likely to be incorrect, by measuring consistency of the predictions w.r.t. multiple prompts and image transformations. We show that our procedure better predicts mistakes, outperforming the popular max logit baseline on selective prediction tasks. Next, we propose a simple and efficient way to improve accuracy on such uncertain images by making use of the WordNet hierarchy; specifically we augment the original class by incorporating its parent and children from the semantic label hierarchy, and plug the augmentation into text promts. We conduct experiments on both CLIP and LiT models with five different ImageNet-based datasets. For CLIP, our method improves the top-1 accuracy by 17.13% on the uncertain subset and 3.6% on the entire ImageNet validation set. We also show that our method improves across ImageNet shifted datasets and other model architectures such as LiT. Our proposed method is hyperparameter-free, requires no additional model training and can be easily scaled to other large multi-modal architectures.
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Massive collection and explosive growth of the huge amount of medical data, demands effective compression for efficient storage, transmission and sharing. Readily available visual data compression techniques have been studied extensively but tailored for nature images/videos, and thus show limited performance on medical data which are of different characteristics. Emerging implicit neural representation (INR) is gaining momentum and demonstrates high promise for fitting diverse visual data in target-data-specific manner, but a general compression scheme covering diverse medical data is so far absent. To address this issue, we firstly derive a mathematical explanation for INR's spectrum concentration property and an analytical insight on the design of compression-oriented INR architecture. Further, we design a funnel shaped neural network capable of covering broad spectrum of complex medical data and achieving high compression ratio. Based on this design, we conduct compression via optimization under given budget and propose an adaptive compression approach SCI, which adaptively partitions the target data into blocks matching the concentrated spectrum envelop of the adopted INR, and allocates parameter with high representation accuracy under given compression ratio. The experiments show SCI's superior performance over conventional techniques and wide applicability across diverse medical data.
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仿真是对机器人系统(例如自动驾驶汽车)进行扩展验证和验证的关键。尽管高保真物理和传感器模拟取得了进步,但在模拟道路使用者的现实行为方面仍然存在一个危险的差距。这是因为,与模拟物理和图形不同,设计人类行为的第一个原理模型通常是不可行的。在这项工作中,我们采用了一种数据驱动的方法,并提出了一种可以学会从现实世界驱动日志中产生流量行为的方法。该方法通过将交通仿真问题分解为高级意图推理和低级驾驶行为模仿,通过利用驾驶行为的双层层次结构来实现高样本效率和行为多样性。该方法还结合了一个计划模块,以获得稳定的长马行为。我们从经验上验证了我们的方法,即交通模拟(位)的双层模仿,并具有来自两个大规模驾驶数据集的场景,并表明位表明,在现实主义,多样性和长途稳定性方面可以达到平衡的交通模拟性能。我们还探索了评估行为现实主义的方法,并引入了一套评估指标以进行交通模拟。最后,作为我们的核心贡献的一部分,我们开发和开源一个软件工具,该工具将跨不同驱动数据集的数据格式统一,并将现有数据集将场景转换为交互式仿真环境。有关其他信息和视频,请参见https://sites.google.com/view/nvr-bits2022/home
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知识图(kg)嵌入是一种主流方法,用于推理不完整的kg。但是,受其固有浅层和静态体系结构的限制,它们几乎无法处理对复杂逻辑查询的不断上升,这些查询包括逻辑运算符,估算的边缘,多个源实体和未知的中间实体。在这项工作中,我们通过掩盖的预训练和微调策略介绍了知识图变压器(kgtransformer)。我们设计了一种kg三重变换方法,以使变压器能够处理kg,这是通过稀疏(MOE)稀疏激活的混合物进一步增强的。然后,我们将复杂的逻辑查询作为掩盖预测提出,并引入了两阶段掩盖的预训练策略,以提高可转移性和概括性。在两个基准上进行的广泛实验表明,KGTRANSFORMER可以始终超过基于KG的基准和九个内域和室外推理任务的高级编码。此外,KGTRANSFORMER可以通过提供解释给定答案的完整推理路径来解释性。
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机器学习中的一个关键挑战是类不平衡,其中某些类(多数类)的样本大小远高于其他类别(少数族裔)。如果我们要直接培训分类器在不平衡的数据上,则分类器更有可能将新样本预测为多数类。在极端情况下,分类器可以完全忽略少数群体。这可能在医疗保健中具有严重的社会学意义,因为少数群体通常是疾病类别(例如,死亡或临床阳性检测结果)。在本文中,我们介绍了一种软件,该软件使用生成的对抗网络来超过少数群体,以改善下游分类。据我们所知,这是允许多类分类的第一个工具(目标可以具有任意数量的类)。该工具的代码在我们的GitHub存储库中公开可用(https://github.com/yuxiaohuang/research/research/tree/master/gwu/working/working/cigan/code)。
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尽管完全监督的人类骨架序列建模成功,但使用自我监督的预训练进行骨架序列表示学习一直是一个活跃的领域,因为很难在大规模上获取特定于任务的骨骼注释。最近的研究重点是使用对比学习学习视频级别的时间和歧视性信息,但忽略了人类骨骼的层次空间时间。与视频级别的这种表面监督不同,我们提出了一种自我监督的分层预训练方案,该方案纳入了基于层次变压器的骨骼骨骼序列编码器(HI-TRS),以明确捕获空间,短期和长期和长期框架,剪辑和视频级别的时间依赖性分别。为了通过HI-TR评估提出的自我监督预训练方案,我们进行了广泛的实验,涵盖了三个基于骨架的下游任务,包括动作识别,动作检测和运动预测。根据监督和半监督评估协议,我们的方法实现了最新的性能。此外,我们证明了我们的模型在训练阶段中学到的先验知识具有强大的下游任务的转移能力。
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在弱光环境下,手持式摄影在长时间的曝光设置下遭受了严重的相机震动。尽管现有的Deblurry算法在暴露良好的模糊图像上表现出了令人鼓舞的性能,但它们仍然无法应对低光快照。在实用的低光脱毛中,复杂的噪声和饱和区是两个主导挑战。在这项工作中,我们提出了一种称为图像的新型非盲脱毛方法,并具有特征空间Wiener Deonervolution网络(Infwide),以系统地解决这些问题。在算法设计方面,Infwide提出了一个两分支的架构,该体系结构明确消除了噪声并幻觉,使图像空间中的饱和区域抑制了特征空间中的响起文物,并将两个互补输出与一个微妙的多尺度融合网络集成在一起高质量的夜间照片浮雕。为了进行有效的网络培训,我们设计了一组损失功能,集成了前向成像模型和向后重建,以形成近环的正则化,以确保深神经网络的良好收敛性。此外,为了优化Infwide在实际弱光条件下的适用性,采用基于物理过程的低光噪声模型来合成现实的嘈杂夜间照片进行模型训练。利用传统的Wiener Deonervolution算法的身体驱动的特征并引起了深层神经网络的表示能力,Infwide可以恢复细节,同时抑制在脱毛期间的不愉快的人工制品。关于合成数据和实际数据的广泛实验证明了所提出的方法的出色性能。
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