Temporal networks are an important type of network whose topological structure changes over time. Compared with methods on static networks, temporal network embedding (TNE) methods are facing three challenges: 1) it cannot describe the temporal dependence across network snapshots; 2) the node embedding in the latent space fails to indicate changes in the network topology; and 3) it cannot avoid a lot of redundant computation via parameter inheritance on a series of snapshots. To this end, we propose a novel temporal network embedding method named Dynamic Cluster Structure Constraint model (DyCSC), whose core idea is to capture the evolution of temporal networks by imposing a temporal constraint on the tendency of the nodes in the network to a given number of clusters. It not only generates low-dimensional embedding vectors for nodes but also preserves the dynamic nonlinear features of temporal networks. Experimental results on multiple realworld datasets have demonstrated the superiority of DyCSC for temporal graph embedding, as it consistently outperforms competing methods by significant margins in multiple temporal link prediction tasks. Moreover, the ablation study further validates the effectiveness of the proposed temporal constraint.
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Clustering is a fundamental problem in network analysis that finds closely connected groups of nodes and separates them from other nodes in the graph, while link prediction is to predict whether two nodes in a network are likely to have a link. The definition of both naturally determines that clustering must play a positive role in obtaining accurate link prediction tasks. Yet researchers have long ignored or used inappropriate ways to undermine this positive relationship. In this article, We construct a simple but efficient clustering-driven link prediction framework(ClusterLP), with the goal of directly exploiting the cluster structures to obtain connections between nodes as accurately as possible in both undirected graphs and directed graphs. Specifically, we propose that it is easier to establish links between nodes with similar representation vectors and cluster tendencies in undirected graphs, while nodes in a directed graphs can more easily point to nodes similar to their representation vectors and have greater influence in their own cluster. We customized the implementation of ClusterLP for undirected and directed graphs, respectively, and the experimental results using multiple real-world networks on the link prediction task showed that our models is highly competitive with existing baseline models. The code implementation of ClusterLP and baselines we use are available at https://github.com/ZINUX1998/ClusterLP.
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时间网络链接预测是网络科学领域的重要任务,并且在实际情况下具有广泛的应用。揭示网络的进化机制对于链接预测至关重要,如何有效利用历史信息来实现时间链接并有效提取网络结构的高阶模式仍然是一个至关重要的挑战。为了解决这些问题,在本文中,我们提出了一个具有调整后的Sigmoid函数和2-Simplex结构(TLPSS)的新型时间链接预测模型。调整后的Sigmoid衰减模式考虑了活跃,衰减和稳定的边缘状态,这适当适合信息的生命周期。此外,引入了由单纯形高阶结构组成的潜在矩阵序列,以增强链接预测方法的性能,因为它在稀疏网络中非常可行。结合信息的生命周期和单纯级结构,通过满足动态网络中时间和结构信息的一致性来实现TLPS的整体性能。六个现实世界数据集的实验结果证明了TLPS的有效性,与其他基线方法相比,我们提出的模型平均提高了链接预测的性能15%。
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时间图代表实体之间的动态关系,并发生在许多现实生活中的应用中,例如社交网络,电子商务,通信,道路网络,生物系统等。他们需要根据其生成建模和表示学习的研究超出与静态图有关的研究。在这项调查中,我们全面回顾了近期针对处理时间图提出的神经时间依赖图表的学习和生成建模方法。最后,我们确定了现有方法的弱点,并讨论了我们最近发表的论文提格的研究建议[24]。
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给定实体及其在Web数据中的交互,可能在不同的时间发生,我们如何找到实体社区并跟踪其演变?在本文中,我们从图形群集的角度处理这项重要任务。最近,通过深层聚类方法,已经实现了各个领域的最新聚类性能。特别是,深图聚类(DGC)方法通过学习节点表示和群集分配在关节优化框架中成功扩展到图形结构的数据。尽管建模选择有所不同(例如,编码器架构),但现有的DGC方法主要基于自动编码器,并使用相同的群集目标和相对较小的适应性。同样,尽管许多现实世界图都是动态的,但以前的DGC方法仅被视为静态图。在这项工作中,我们开发了CGC,这是一个新颖的端到端图形聚类框架,其与现有方法的根本不同。 CGC在对比度图学习框架中学习节点嵌入和群集分配,在多级别方案中仔细选择了正面和负样本,以反映层次结构的社区结构和网络同质。此外,我们将CGC扩展到时间不断发展的数据,其中时间图以增量学习方式执行,并具有检测更改点的能力。对现实世界图的广泛评估表明,所提出的CGC始终优于现有方法。
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图形结构化数据通常在自然界中具有动态字符,例如,在许多现实世界中,链接和节点的添加。近年来见证了对这种图形数据进行建模的动态图神经网络所支付的越来越多的注意力,几乎所有现有方法都假设,当建立新的链接时,应通过学习时间动态来传播邻居节点的嵌入。新的信息。但是,这种方法遭受了这样的限制,如果新连接引入的节点包含嘈杂的信息,那么将其知识传播到其他节点是不可靠的,甚至导致模型崩溃。在本文中,我们提出了Adanet:通过增强动态图神经网络的强化知识适应框架。与以前的方法相反,一旦添加了新链接,就立即更新邻居节点的嵌入方式,Adanet试图自适应地确定由于涉及的新链接而应更新哪些节点。考虑到是否更新一个邻居节点的嵌入的决定将对其他邻居节点产生很大的影响,因此,我们将节点更新的选择作为序列决策问题,并通过强化学习解决此问题。通过这种方式,我们可以将知识自适应地传播到其他节点,以学习健壮的节点嵌入表示。据我们所知,我们的方法构成了通过强化学习的动态图神经网络来探索强大知识适应的首次尝试。在三个基准数据集上进行的广泛实验表明,Adanet可以实现最新的性能。此外,我们通过在数据集中添加不同程度的噪声来执行实验,并定量和定性地说明ADANET的鲁棒性。
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随着对比学习的兴起,无人监督的图形表示学习最近一直蓬勃发展,甚至超过了一些机器学习任务中的监督对应物。图表表示的大多数对比模型学习侧重于最大化本地和全局嵌入之间的互信息,或主要取决于节点级别的对比嵌入。然而,它们仍然不足以全面探索网络拓扑的本地和全球视图。虽然前者认为本地全球关系,但其粗略的全球信息导致本地和全球观点之间的思考。后者注重节点级别对齐,以便全局视图的作用出现不起眼。为避免落入这两个极端情况,我们通过对比群集分配来提出一种新颖的无监督图形表示模型,称为GCCA。通过组合聚类算法和对比学习,它有动力综合利用本地和全球信息。这不仅促进了对比效果,而且还提供了更高质量的图形信息。同时,GCCA进一步挖掘群集级信息,这使得它能够了解除了图形拓扑之外的节点之间的难以捉摸的关联。具体地,我们首先使用不同的图形增强策略生成两个增强的图形,然后使用聚类算法分别获取其群集分配和原型。所提出的GCCA进一步强制不同增强图中的相同节点来通过最小化交叉熵损失来互相识别它们的群集分配。为了展示其有效性,我们将在三个不同的下游任务中与最先进的模型进行比较。实验结果表明,GCCA在大多数任务中具有强大的竞争力。
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准确的交通状况预测为车辆环境协调和交通管制任务提供了坚实的基础。由于道路网络数据在空间分布中的复杂性以及深度学习方法的多样性,有效定义流量数据并充分捕获数据中复杂的空间非线性特征变得具有挑战性。本文将两种分层图池方法应用于流量预测任务,以减少图形信息冗余。首先,本文验证了流量预测任务中层次图池方法的有效性。分层图合并方法与其他基线在预测性能上形成鲜明对比。其次,应用了两种主流分层图池方法,节点群集池和节点下降池,用于分析流量预测中的优势和弱点。最后,对于上述图神经网络,本文比较了不同图网络输入对流量预测准确性的预测效应。分析和汇总定义图网络的有效方法。
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Graph learning is a popular approach for performing machine learning on graph-structured data. It has revolutionized the machine learning ability to model graph data to address downstream tasks. Its application is wide due to the availability of graph data ranging from all types of networks to information systems. Most graph learning methods assume that the graph is static and its complete structure is known during training. This limits their applicability since they cannot be applied to problems where the underlying graph grows over time and/or new tasks emerge incrementally. Such applications require a lifelong learning approach that can learn the graph continuously and accommodate new information whilst retaining previously learned knowledge. Lifelong learning methods that enable continuous learning in regular domains like images and text cannot be directly applied to continuously evolving graph data, due to its irregular structure. As a result, graph lifelong learning is gaining attention from the research community. This survey paper provides a comprehensive overview of recent advancements in graph lifelong learning, including the categorization of existing methods, and the discussions of potential applications and open research problems.
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Deep learning has revolutionized many machine learning tasks in recent years, ranging from image classification and video processing to speech recognition and natural language understanding. The data in these tasks are typically represented in the Euclidean space. However, there is an increasing number of applications where data are generated from non-Euclidean domains and are represented as graphs with complex relationships and interdependency between objects. The complexity of graph data has imposed significant challenges on existing machine learning algorithms. Recently, many studies on extending deep learning approaches for graph data have emerged. In this survey, we provide a comprehensive overview of graph neural networks (GNNs) in data mining and machine learning fields. We propose a new taxonomy to divide the state-of-the-art graph neural networks into four categories, namely recurrent graph neural networks, convolutional graph neural networks, graph autoencoders, and spatial-temporal graph neural networks. We further discuss the applications of graph neural networks across various domains and summarize the open source codes, benchmark data sets, and model evaluation of graph neural networks. Finally, we propose potential research directions in this rapidly growing field.
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Graph AutoCododers(GAE)和变分图自动编码器(VGAE)作为链接预测的强大方法出现。他们的表现对社区探测问题的印象不那么令人印象深刻,根据最近和同意的实验评估,它们的表现通常超过了诸如louvain方法之类的简单替代方案。目前尚不清楚可以通过GAE和VGAE改善社区检测的程度,尤其是在没有节点功能的情况下。此外,不确定是否可以在链接预测上同时保留良好的性能。在本文中,我们表明,可以高精度地共同解决这两个任务。为此,我们介绍和理论上研究了一个社区保留的消息传递方案,通过在计算嵌入空间时考虑初始图形结构和基于模块化的先验社区来掺杂我们的GAE和VGAE编码器。我们还提出了新颖的培训和优化策略,包括引入一个模块化的正规器,以补充联合链路预测和社区检测的现有重建损失。我们通过对各种现实世界图的深入实验验证,证明了方法的经验有效性,称为模块化感知的GAE和VGAE。
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许多实际关系系统,如社交网络和生物系统,包含动态相互作用。在学习动态图形表示时,必须采用连续的时间信息和几何结构。主流工作通过消息传递网络(例如,GCN,GAT)实现拓扑嵌入。另一方面,时间演进通常通过在栅极机构中具有方便信息过滤的存储单元(例如,LSTM或GU)来表达。但是,由于过度复杂的编码,这种设计可以防止大规模的输入序列。这项工作从自我关注的哲学中学习,并提出了一种高效的基于频谱的神经单元,采用信息的远程时间交互。发达的频谱窗口单元(SWINIT)模型预测了具有保证效率的可扩展动态图形。该架构与一些构成随机SVD,MLP和图形帧卷积的一些简单的有效计算块组装。 SVD加MLP模块编码动态图事件的长期特征演进。帧卷积中的快速帧图形变换嵌入了结构动态。两种策略都提高了模型对可扩展分析的能力。特别地,迭代的SVD近似度将注意力的计算复杂性缩小到具有n个边缘和D边缘特征的动态图形的关注的计算复杂性,并且帧卷积的多尺度变换允许在网络训练中具有足够的可扩展性。我们的Swinit在各种在线连续时间动态图表学习任务中实现了最先进的性能,而与基线方法相比,可学习参数的数量可达七倍。
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Deep learning has been shown to be successful in a number of domains, ranging from acoustics, images, to natural language processing. However, applying deep learning to the ubiquitous graph data is non-trivial because of the unique characteristics of graphs. Recently, substantial research efforts have been devoted to applying deep learning methods to graphs, resulting in beneficial advances in graph analysis techniques. In this survey, we comprehensively review the different types of deep learning methods on graphs. We divide the existing methods into five categories based on their model architectures and training strategies: graph recurrent neural networks, graph convolutional networks, graph autoencoders, graph reinforcement learning, and graph adversarial methods. We then provide a comprehensive overview of these methods in a systematic manner mainly by following their development history. We also analyze the differences and compositions of different methods. Finally, we briefly outline the applications in which they have been used and discuss potential future research directions.
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Inferring missing links or detecting spurious ones based on observed graphs, known as link prediction, is a long-standing challenge in graph data analysis. With the recent advances in deep learning, graph neural networks have been used for link prediction and have achieved state-of-the-art performance. Nevertheless, existing methods developed for this purpose are typically discriminative, computing features of local subgraphs around two neighboring nodes and predicting potential links between them from the perspective of subgraph classification. In this formalism, the selection of enclosing subgraphs and heuristic structural features for subgraph classification significantly affects the performance of the methods. To overcome this limitation, this paper proposes a novel and radically different link prediction algorithm based on the network reconstruction theory, called GraphLP. Instead of sampling positive and negative links and heuristically computing the features of their enclosing subgraphs, GraphLP utilizes the feature learning ability of deep-learning models to automatically extract the structural patterns of graphs for link prediction under the assumption that real-world graphs are not locally isolated. Moreover, GraphLP explores high-order connectivity patterns to utilize the hierarchical organizational structures of graphs for link prediction. Our experimental results on all common benchmark datasets from different applications demonstrate that the proposed method consistently outperforms other state-of-the-art methods. Unlike the discriminative neural network models used for link prediction, GraphLP is generative, which provides a new paradigm for neural-network-based link prediction.
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最近从静态图中学习了最近的成功,但是尽管存在普遍存在,但从时间不断发展的图表中学习仍然具有挑战性。我们为特定于动态图的链接预测设计了新的,更严格的评估程序,这些预测反映了现实世界的考虑,并且可以更好地比较不同的方法的优势和劣势。特别是,我们创建了两种可视化技术,以了解随着时间的推移的重复图案。他们表明,以后的时间步骤重复了许多边缘。因此,我们提出了一个称为EdgeBank的纯记忆基线。它在多个设置中实现了令人惊讶的强劲性能,部分原因是当前评估设置中使用的简单负面边缘。因此,我们引入了另外两种具有挑战性的负面抽样策略,可以改善鲁棒性,并可以更好地匹配现实世界的应用程序。最后,我们从当前基准中缺少各种域中介绍了五个新的动态图数据集,从而为未来的研究提供了新的挑战和机会。
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链接预测是一项重要的任务,在各个域中具有广泛的应用程序。但是,大多数现有的链接预测方法都假定给定的图遵循同质的假设,并设计基于相似性的启发式方法或表示学习方法来预测链接。但是,许多现实世界图是异性图,同义假设不存在,这挑战了现有的链接预测方法。通常,在异性图中,有许多引起链接形成的潜在因素,并且两个链接的节点在一个或两个因素中往往相似,但在其他因素中可能是不同的,导致总体相似性较低。因此,一种方法是学习每个节点的分离表示形式,每个矢量捕获一个因子上的节点的潜在表示,这铺平了一种方法来模拟异性图中的链接形成,从而导致更好的节点表示学习和链接预测性能。但是,对此的工作非常有限。因此,在本文中,我们研究了一个新的问题,该问题是在异性图上进行链接预测的分离表示学习。我们提出了一种新颖的框架分解,可以通过建模链接形成并执行感知因素的消息来学习以促进链接预测来学习解开的表示形式。在13个现实世界数据集上进行的广泛实验证明了Disenlink对异性恋和血友病图的链接预测的有效性。我们的代码可从https://github.com/sjz5202/disenlink获得
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Variational Graph Autoencoders (VGAEs) are powerful models for unsupervised learning of node representations from graph data. In this work, we systematically analyze modeling node attributes in VGAEs and show that attribute decoding is important for node representation learning. We further propose a new learning model, interpretable NOde Representation with Attribute Decoding (NORAD). The model encodes node representations in an interpretable approach: node representations capture community structures in the graph and the relationship between communities and node attributes. We further propose a rectifying procedure to refine node representations of isolated notes, improving the quality of these nodes' representations. Our empirical results demonstrate the advantage of the proposed model when learning graph data in an interpretable approach.
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由于其独立性与标签及其稳健性的独立性,自我监督的学习最近引起了很多关注。目前关于本主题的研究主要使用诸如图形结构的静态信息,但不能很好地捕获诸如边缘时间戳的动态信息。现实图形通常是动态的,这意味着节点之间的交互发生在特定时间。本文提出了一种自我监督的动态图形表示学习框架(DYSUBC),其定义了一个时间子图对比学学习任务,以同时学习动态图的结构和进化特征。具体地,首先提出了一种新的时间子图采样策略,其将动态图的每个节点作为中心节点提出,并使用邻域结构和边缘时间戳来采样相应的时间子图。然后根据在编码每个子图中的节点之后,根据中心节点上的邻域节点的影响设计子图表示功能。最后,定义了结构和时间对比损失,以最大化节点表示和时间子图表示之间的互信息。五个现实数据集的实验表明(1)DySubc比下游链路预测任务中的两个图形对比学习模型和四个动态图形表示学习模型更好地表现出更好的相关基线,(2)使用时间信息不能使用只有更有效的子图,还可以通过时间对比损失来学习更好的表示。
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学习在动态环境中网络的低维拓扑表示由于许多真实网络的时间不断发展而引起了很多关注。动态网络嵌入(DNE)的主要和共同目标是有效更新节点嵌入品,同时在每次步骤保留网络拓扑时。大多数现有DNE方法的想法是捕获受影响的节点(而不是所有节点)的拓扑变化,并因此更新节点嵌入。遗憾的是,这种近似虽然可以提高效率,但是在每次步骤中不能有效地保留动态网络的全局拓扑,因为没有考虑通过高阶接近传播的累积拓扑变化的非活动子网。为了解决这一挑战,我们提出了一种新颖的节点选择策略,以在网络上多移地选择代表节点,这与基于Skip-gram的嵌入方法的新增量学习范例协调。广泛的实验显示Glodyne,较小的节点部分被选中,可以实现优越或相当的性能W.R.T.在三个典型的下游任务中最先进的DNE方法。特别是,Glodyne显着优于图形重建任务中的其他方法,这表明了其全球拓扑保存能力。源代码可在https://github.com/houchengbin/glodyne获得
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图表表示学习是一种快速增长的领域,其中一个主要目标是在低维空间中产生有意义的图形表示。已经成功地应用了学习的嵌入式来执行各种预测任务,例如链路预测,节点分类,群集和可视化。图表社区的集体努力提供了数百种方法,但在所有评估指标下没有单一方法擅长,例如预测准确性,运行时间,可扩展性等。该调查旨在通过考虑算法来评估嵌入方法的所有主要类别的图表变体,参数选择,可伸缩性,硬件和软件平台,下游ML任务和多样化数据集。我们使用包含手动特征工程,矩阵分解,浅神经网络和深图卷积网络的分类法组织了图形嵌入技术。我们使用广泛使用的基准图表评估了节点分类,链路预测,群集和可视化任务的这些类别算法。我们在Pytorch几何和DGL库上设计了我们的实验,并在不同的多核CPU和GPU平台上运行实验。我们严格地审查了各种性能指标下嵌入方法的性能,并总结了结果。因此,本文可以作为比较指南,以帮助用户选择最适合其任务的方法。
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