个性化Pagerank(PPR)是无监督学习图表(例如节点排名,标签和图形嵌入)的基本工具。但是,尽管数据隐私是最近的最重要问题之一,但现有的PPR算法并非旨在保护用户隐私。 PPR对输入图边缘高度敏感:仅一个边缘的差异可能会导致PPR矢量发生很大变化,并可能泄漏私人用户数据。在这项工作中,我们提出了一种输出近似PPR的算法,并证明对输入边缘的敏感性有界限。此外,我们证明,当输入图具有较大的程度时,我们的算法与非私有算法相似。我们敏感性的PPR直接暗示了用于几种图形学习工具的私有算法,例如差异私有(DP)PPR排名,DP节点分类和DP节点嵌入。为了补充我们的理论分析,我们还经验验证了算法的实际性能。
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对图形卷积网络(GCN)的兴趣激增,已经产生了数千种GCN变体,每年引入数百种。相比之下,许多GCN模型仅重复使用少数基准数据集,因为人们的兴趣图(例如社交或商业网络)都是专有的。我们提出了一个新的图生成问题,以使源图分布之后,为GCN生成各种基准图(可能是专有的),具有三个要求:1)基准有效性作为GCN研究源图的替代品, 2)可扩展性处理大型现实图形,以及3)最终用户的隐私保证。借助新的图形编码方案,我们将大规模的图生成问题重新构架为中长长序列生成问题,并将变压器体系结构的强生成功率应用于图形域。跨大量图生成模型进行的广泛实验表明,我们的模型可以成功生成基准图,并具有实际的图形结构,节点属性和基准GCNS在节点分类任务上所需的节点标签。
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TensorFlow GNN(TF-GNN)是张量曲线的图形神经网络的可扩展库。它是从自下而上设计的,以支持当今信息生态系统中发生的丰富的异质图数据。Google的许多生产模型都使用TF-GNN,最近已作为开源项目发布。在本文中,我们描述了TF-GNN数据模型,其KERAS建模API以及相关功能,例如图形采样,分布式训练和加速器支持。
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从社会或商业平台等工业生态系统连续发出的数据通常表示为由多种节点/边缘类型组成的异质图(HG)。使用称为异质图神经网络(HGNN)的HGS的最先进的图形学习方法用于学习深层上下文信息形式表示。但是,来自工业应用程序的许多HG数据集都遭受节点类型之间的标签失衡。由于没有直接学习使用扎根于不同节点类型的标签的直接方法,因此HGNN仅应用于具有丰富标签的几个节点类型。我们为HGNN提出了一个称为知识转移网络(KTN)的零射击传输学习模块,该模块通过HG中给出的丰富关系信息将知识从标签的源节点类型转移到零标记的节点类型。 KTN源自我们在这项工作中引入的理论关系,在HGNN模型中给出的每个节点类型的不同特征提取器之间。 KTN将6种不同类型的HGNN模型的性能提高了960%,以推断零标记的节点类型,并且在HGS上的18个不同的转移学习任务中,最高的最先进的转移学习基线胜过最高的最高转移学习基线。
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尽管图形神经网络(GNNS)领域的进步,但目前仅使用少量数据集来评估新模型。这种持续依赖少数数据集提供了对模型之间的性能差异的最小见解,对于可能具有与用作学术基准的数据集有很大不同的工业从业人员而言,尤其具有挑战性。在Google在GNN基础架构和开源软件方面的工作过程中,我们试图开发改进的基准,这些基准可健壮,可调,可扩展且可推广。在这项工作中,我们介绍了GraphWorld,这是一种新的方法和系统,用于对任何可疑的GNN任务进行任意大量的合成图种群进行基准测试GNN模型。 GraphWorld允许用户有效地生成具有数百万个统计上不同数据集的世界。它可访问,可扩展且易于使用。 GraphWorld可以在没有专门硬件的情况下在一台计算机上运行,​​也可以轻松地扩展到在任意群集或云框架上运行。使用GraphWorld,用户对Graph Generator参数具有细粒度的控制,并且可以使用内置的超参数调整基准测试任意GNN模型。我们从GraphWorld实验中介绍了有关数以百亿个基准数据集中数以万计的GNN模型的性能特征的见解。我们进一步表明,GraphWorld有效地探索了标准基准测试的基准数据集空间区域,从而揭示了在历史上无法获得的模型之间的比较。使用GraphWorld,我们还能够研究图形属性与任务性能指标之间的关系,这对于经典的现实基准集合而言,这几乎是不可能的。
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图形神经网络(GNN)已在许多图分析任务(例如节点分类和链接预测)上实现了最新结果。然而,事实证明,图形群集等图形上的重要无监督问题对GNN的进步具有更大的抵抗力。图群集的总体目标与GNN中的节点合并相同 - 这是否意味着GNN池方法在聚类图上做得很好?令人惊讶的是,答案是没有的 - 当前的GNN合并方法通常无法恢复群集结构,而在简单的基线(例如应用于学习的表示形式上的K-均值)良好工作的情况下。我们通过仔细设计一组实验来进一步研究,以研究图形结构和属性数据中的不同信噪比情景。为了解决这些方法在聚类中的性能不佳,我们引入了深层模块化网络(DMON),这是一种受群集质量模块化量度启发的无监督池方法,并显示了它如何解决现实世界图的挑战性聚类结构的恢复。同样,在现实世界中,我们表明DMON产生的高质量簇与地面真相标签密切相关,从而实现了最先进的结果,比不同指标的其他合并方法提高了40%以上。
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Existing popular methods for semi-supervised learning with Graph Neural Networks (such as the Graph Convolutional Network) provably cannot learn a general class of neighborhood mixing relationships. To address this weakness, we propose a new model, MixHop, that can learn these relationships, including difference operators, by repeatedly mixing feature representations of neighbors at various distances. MixHop requires no additional memory or computational complexity, and outperforms on challenging baselines. In addition, we propose sparsity regularization that allows us to visualize how the network prioritizes neighborhood information across different graph datasets. Our analysis of the learned architectures reveals that neighborhood mixing varies per datasets. 1 We use "like", as graph edges are not axis-aligned.
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We present DeepWalk, a novel approach for learning latent representations of vertices in a network. These latent representations encode social relations in a continuous vector space, which is easily exploited by statistical models. Deep-Walk generalizes recent advancements in language modeling and unsupervised feature learning (or deep learning) from sequences of words to graphs.DeepWalk uses local information obtained from truncated random walks to learn latent representations by treating walks as the equivalent of sentences. We demonstrate DeepWalk's latent representations on several multi-label network classification tasks for social networks such as Blog-Catalog, Flickr, and YouTube. Our results show that Deep-Walk outperforms challenging baselines which are allowed a global view of the network, especially in the presence of missing information. DeepWalk's representations can provide F1 scores up to 10% higher than competing methods when labeled data is sparse. In some experiments, Deep-Walk's representations are able to outperform all baseline methods while using 60% less training data.DeepWalk is also scalable. It is an online learning algorithm which builds useful incremental results, and is trivially parallelizable. These qualities make it suitable for a broad class of real world applications such as network classification, and anomaly detection.
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Adversarial imitation learning (AIL) has become a popular alternative to supervised imitation learning that reduces the distribution shift suffered by the latter. However, AIL requires effective exploration during an online reinforcement learning phase. In this work, we show that the standard, naive approach to exploration can manifest as a suboptimal local maximum if a policy learned with AIL sufficiently matches the expert distribution without fully learning the desired task. This can be particularly catastrophic for manipulation tasks, where the difference between an expert and a non-expert state-action pair is often subtle. We present Learning from Guided Play (LfGP), a framework in which we leverage expert demonstrations of multiple exploratory, auxiliary tasks in addition to a main task. The addition of these auxiliary tasks forces the agent to explore states and actions that standard AIL may learn to ignore. Additionally, this particular formulation allows for the reusability of expert data between main tasks. Our experimental results in a challenging multitask robotic manipulation domain indicate that LfGP significantly outperforms both AIL and behaviour cloning, while also being more expert sample efficient than these baselines. To explain this performance gap, we provide further analysis of a toy problem that highlights the coupling between a local maximum and poor exploration, and also visualize the differences between the learned models from AIL and LfGP.
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Location-aware networks will introduce new services and applications for modern convenience, surveillance, and public safety. In this paper, we consider the problem of cooperative localization in a wireless network where the position of certain anchor nodes can be controlled. We introduce an active planning method that aims at moving the anchors such that the information gain of future measurements is maximized. In the control layer of the proposed method, control inputs are calculated by minimizing the traces of approximate inverse Bayesian Fisher information matrixes (FIMs). The estimation layer computes estimates of the agent states and provides Gaussian representations of marginal posteriors of agent positions to the control layer for approximate Bayesian FIM computations. Based on a cost function that accumulates Bayesian FIM contributions over a sliding window of discrete future timesteps, a receding horizon (RH) control is performed. Approximations that make it possible to solve the resulting tree-search problem efficiently are also discussed. A numerical case study demonstrates the intelligent behavior of a single controlled anchor in a 3-D scenario and the resulting significantly improved localization accuracy.
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