在过去四年中,在过去四年中提高了更多的注意力,以动态网络嵌入。然而,现有的动态嵌入方法将问题视为仅限于全球循环状态序列的拓扑演变的问题。我们提出了一种新颖的嵌入算法,步行时间,基于从根本上不同的时间处理,允许局部考虑连续发生的现象;虽然其他人认为全球时间步骤是动态环境的一流公民,但我们将由时间和拓扑本地交互组成的流量作为我们的基元,而无需任何离散化或对准时间相关的属性是必要的。关键词:动态网络,表示学习,动态图嵌入,时间偏见路径,时间拓扑流量,时间随机散步,时间网络,真实归因的知识图形,流媒体图形,在线网络,异步图形,异步网络,图形算法,深度学习,网络分析,Datamining,网络科学
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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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Community detection is the task of discovering groups of nodes sharing similar patterns within a network. With recent advancements in deep learning, methods utilizing graph representation learning and deep clustering have shown great results in community detection. However, these methods often rely on the topology of networks (i) ignoring important features such as network heterogeneity, temporality, multimodality, and other possibly relevant features. Besides, (ii) the number of communities is not known a priori and is often left to model selection. In addition, (iii) in multimodal networks all nodes are assumed to be symmetrical in their features; while true for homogeneous networks, most of the real-world networks are heterogeneous where feature availability often varies. In this paper, we propose a novel framework (named MGTCOM) that overcomes the above challenges (i)--(iii). MGTCOM identifies communities through multimodal feature learning by leveraging a new sampling technique for unsupervised learning of temporal embeddings. Importantly, MGTCOM is an end-to-end framework optimizing network embeddings, communities, and the number of communities in tandem. In order to assess its performance, we carried out an extensive evaluation on a number of multimodal networks. We found out that our method is competitive against state-of-the-art and performs well in inductive inference.
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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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网络表示学习(NRL)方法在过去几年中受到了重大关注,因此由于它们在几个图形分析问题中的成功,包括节点分类,链路预测和聚类。这种方法旨在以一种保留网络的结构信息的方式将网络的每个顶点映射到低维空间中。特别感兴趣的是基于随机行走的方法;这些方法将网络转换为节点序列的集合,旨在通过预测序列内每个节点的上下文来学习节点表示。在本文中,我们介绍了一种通用框架,以增强通过基于主题信息的随机行走方法获取的节点的嵌入。类似于自然语言处理中局部单词嵌入的概念,所提出的模型首先将每个节点分配给潜在社区,并有利于各种统计图模型和社区检测方法,然后了解增强的主题感知表示。我们在两个下游任务中评估我们的方法:节点分类和链路预测。实验结果表明,通过纳入节点和社区嵌入,我们能够以广泛的广泛的基线NRL模型表明。
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图形嵌入,代表数值向量的本地和全局邻域信息,是广泛的现实系统数学建模的关键部分。在嵌入算法中,事实证明,基于步行的随机算法非常成功。这些算法通过创建许多随机步行,并重新定义步骤来收集信息。创建随机步行是嵌入过程中最苛刻的部分。计算需求随着网络的规模而增加。此外,对于现实世界网络,考虑到相同基础上的所有节点,低度节点的丰度都会造成不平衡的数据问题。在这项工作中,提出了一种计算较少且节点连接性统一抽样方法。在提出的方法中,随机步行的数量与节点的程度成比例地创建。当将算法应用于大图时,所提出的算法的优点将变得更加增强。提出了使用两个网络(即Cora和Citeseer)进行比较研究。与固定数量的步行情况相比,提出的方法需要减少50%的计算工作,以达到节点分类和链接预测计算的相同精度。
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Machine learning on graphs is an important and ubiquitous task with applications ranging from drug design to friendship recommendation in social networks. The primary challenge in this domain is finding a way to represent, or encode, graph structure so that it can be easily exploited by machine learning models. Traditionally, machine learning approaches relied on user-defined heuristics to extract features encoding structural information about a graph (e.g., degree statistics or kernel functions). However, recent years have seen a surge in approaches that automatically learn to encode graph structure into low-dimensional embeddings, using techniques based on deep learning and nonlinear dimensionality reduction. Here we provide a conceptual review of key advancements in this area of representation learning on graphs, including matrix factorization-based methods, random-walk based algorithms, and graph neural networks. We review methods to embed individual nodes as well as approaches to embed entire (sub)graphs. In doing so, we develop a unified framework to describe these recent approaches, and we highlight a number of important applications and directions for future work.
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一组广泛建立的无监督节点嵌入方法可以解释为由两个独特的步骤组成:i)基于兴趣图的相似性矩阵的定义,然后是II)ii)该矩阵的明确或隐式因素化。受这个观点的启发,我们提出了框架的两个步骤的改进。一方面,我们建议根据自由能距离编码节点相似性,该自由能距离在最短路径和通勤时间距离之间进行了插值,从而提供了额外的灵活性。另一方面,我们根据损耗函数提出了一种基质分解方法,该方法将Skip-Gram模型的损失函数推广到任意相似性矩阵。与基于广泛使用的$ \ ell_2 $损失的因素化相比,该方法可以更好地保留与较高相似性分数相关的节点对。此外,它可以使用高级自动分化工具包轻松实现,并通过利用GPU资源进行有效计算。在现实世界数据集上的节点聚类,节点分类和链接预测实验证明了与最先进的替代方案相比,合并基于自由能的相似性以及所提出的矩阵分解的有效性。
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复杂网络分析的最新进展为不同领域的应用开辟了广泛的可能性。网络分析的功能取决于节点特征。基于拓扑的节点特征是对局部和全局空间关系和节点连接结构的实现。因此,收集有关节点特征的正确信息和相邻节点的连接结构在复杂网络分析中在节点分类和链接预测中起着最突出的作用。目前的工作介绍了一种新的特征抽象方法,即基于嵌入匿名随机步行向量上的匿名随机步行,即过渡概率矩阵(TPM)。节点特征向量由从预定义半径中的一组步行中获得的过渡概率组成。过渡概率与局部连接结构直接相关,因此正确嵌入到特征向量上。在节点识别/分类中测试了建议的嵌入方法的成功,并在三个常用的现实世界网络上进行了链接预测。在现实世界网络中,具有相似连接结构的节点很常见。因此,从类似网络中获取新网络预测的信息是一种显着特征,它使所提出的算法在跨网络概括任务方面优于最先进的算法。
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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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在低维空间中节点的学习表示是一项至关重要的任务,在网络分析中具有许多有趣的应用,包括链接预测,节点分类和可视化。解决此问题的两种流行方法是矩阵分解和基于步行的随机模型。在本文中,我们旨在将两全其美的最好的人融合在一起,以学习节点表示。特别是,我们提出了一个加权矩阵分解模型,该模型编码有关网络节点的随机步行信息。这种新颖的表述的好处是,它使我们能够利用内核函数,而无需意识到确切的接近矩阵,从而增强现有矩阵分解方法的表达性,并减轻其计算复杂性。我们通过多个内核学习公式扩展了方法,该公式提供了学习内核作为以数据驱动方式的词典的线性组合的灵活性。我们在现实世界网络上执行经验评估,表明所提出的模型优于基线节点嵌入下游机器学习任务中的算法。
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A key challenge in social network analysis is understanding the position, or stance, of people in the graph on a large set of topics. While past work has modeled (dis)agreement in social networks using signed graphs, these approaches have not modeled agreement patterns across a range of correlated topics. For instance, disagreement on one topic may make disagreement(or agreement) more likely for related topics. We propose the Stance Embeddings Model(SEM), which jointly learns embeddings for each user and topic in signed social graphs with distinct edge types for each topic. By jointly learning user and topic embeddings, SEM is able to perform cold-start topic stance detection, predicting the stance of a user on topics for which we have not observed their engagement. We demonstrate the effectiveness of SEM using two large-scale Twitter signed graph datasets we open-source. One dataset, TwitterSG, labels (dis)agreements using engagements between users via tweets to derive topic-informed, signed edges. The other, BirdwatchSG, leverages community reports on misinformation and misleading content. On TwitterSG and BirdwatchSG, SEM shows a 39% and 26% error reduction respectively against strong baselines.
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最近有一项激烈的活动在嵌入非常高维和非线性数据结构的嵌入中,其中大部分在数据科学和机器学习文献中。我们分四部分调查这项活动。在第一部分中,我们涵盖了非线性方法,例如主曲线,多维缩放,局部线性方法,ISOMAP,基于图形的方法和扩散映射,基于内核的方法和随机投影。第二部分与拓扑嵌入方法有关,特别是将拓扑特性映射到持久图和映射器算法中。具有巨大增长的另一种类型的数据集是非常高维网络数据。第三部分中考虑的任务是如何将此类数据嵌入中等维度的向量空间中,以使数据适合传统技术,例如群集和分类技术。可以说,这是算法机器学习方法与统计建模(所谓的随机块建模)之间的对比度。在论文中,我们讨论了两种方法的利弊。调查的最后一部分涉及嵌入$ \ mathbb {r}^ 2 $,即可视化中。提出了三种方法:基于第一部分,第二和第三部分中的方法,$ t $ -sne,UMAP和大节。在两个模拟数据集上进行了说明和比较。一个由嘈杂的ranunculoid曲线组成的三胞胎,另一个由随机块模型和两种类型的节点产生的复杂性的网络组成。
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图表上的表示学习(也称为图形嵌入)显示了其对一系列机器学习应用程序(例如分类,预测和建议)的重大影响。但是,现有的工作在很大程度上忽略了现代应用程序中图和边缘的属性(或属性)中包含的丰富信息,例如,属性图表示的节点和边缘。迄今为止,大多数现有的图形嵌入方法要么仅关注具有图形拓扑的普通图,要么仅考虑节点上的属性。我们提出了PGE,这是一个图形表示学习框架,该框架将节点和边缘属性都包含到图形嵌入过程中。 PGE使用节点聚类来分配偏差来区分节点的邻居,并利用多个数据驱动的矩阵来汇总基于偏置策略采样的邻居的属性信息。 PGE采用了流行的邻里聚合归纳模型。我们通过显示PGE如何实现更好的嵌入结果的详细分析,并验证PGE的性能,而不是最新的嵌入方法嵌入方法在基准应用程序上的嵌入方法,例如节点分类和对现实世界中的链接预测数据集。
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Graph is an important data representation which appears in a wide diversity of real-world scenarios. Effective graph analytics provides users a deeper understanding of what is behind the data, and thus can benefit a lot of useful applications such as node classification, node recommendation, link prediction, etc. However, most graph analytics methods suffer the high computation and space cost. Graph embedding is an effective yet efficient way to solve the graph analytics problem. It converts the graph data into a low dimensional space in which the graph structural information and graph properties are maximumly preserved. In this survey, we conduct a comprehensive review of the literature in graph embedding. We first introduce the formal definition of graph embedding as well as the related concepts. After that, we propose two taxonomies of graph embedding which correspond to what challenges exist in different graph embedding problem settings and how the existing work address these challenges in their solutions. Finally, we summarize the applications that graph embedding enables and suggest four promising future research directions in terms of computation efficiency, problem settings, techniques and application scenarios.
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Prediction tasks over nodes and edges in networks require careful effort in engineering features used by learning algorithms. Recent research in the broader field of representation learning has led to significant progress in automating prediction by learning the features themselves. However, present feature learning approaches are not expressive enough to capture the diversity of connectivity patterns observed in networks.Here we propose node2vec, an algorithmic framework for learning continuous feature representations for nodes in networks. In node2vec, we learn a mapping of nodes to a low-dimensional space of features that maximizes the likelihood of preserving network neighborhoods of nodes. We define a flexible notion of a node's network neighborhood and design a biased random walk procedure, which efficiently explores diverse neighborhoods. Our algorithm generalizes prior work which is based on rigid notions of network neighborhoods, and we argue that the added flexibility in exploring neighborhoods is the key to learning richer representations.We demonstrate the efficacy of node2vec over existing state-ofthe-art techniques on multi-label classification and link prediction in several real-world networks from diverse domains. Taken together, our work represents a new way for efficiently learning stateof-the-art task-independent representations in complex networks.
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图形嵌入是图形节点到一组向量的转换。良好的嵌入应捕获图形拓扑,节点与节点的关系以及有关图,其子图和节点的其他相关信息。如果实现了这些目标,则嵌入是网络中有意义的,可理解的,可理解的压缩表示形式,可用于其他机器学习工具,例如节点分类,社区检测或链接预测。主要的挑战是,需要确保嵌入很好地描述图形的属性。结果,选择最佳嵌入是一项具有挑战性的任务,并且通常需要领域专家。在本文中,我们在现实世界网络和人为生成的网络上进行了一系列广泛的实验,并使用选定的图嵌入算法进行了一系列的实验。根据这些实验,我们制定了两个一般结论。首先,如果需要在运行实验之前选择一种嵌入算法,则Node2Vec是最佳选择,因为它在我们的测试中表现最好。话虽如此,在所有测试中都没有单一的赢家,此外,大多数嵌入算法都具有应该调整并随机分配的超参数。因此,如果可能的话,我们对从业者的主要建议是生成几个问题的嵌入,然后使用一个通用框架,该框架为无监督的图形嵌入比较提供了工具。该框架(最近在文献中引入并在GitHub存储库中很容易获得)将分歧分数分配给嵌入,以帮助区分好的分数和不良的分数。
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本次调查绘制了用于分析社交媒体数据的生成方法的研究状态的广泛的全景照片(Sota)。它填补了空白,因为现有的调查文章在其范围内或被约会。我们包括两个重要方面,目前正在挖掘和建模社交媒体的重要性:动态和网络。社会动态对于了解影响影响或疾病的传播,友谊的形成,友谊的形成等,另一方面,可以捕获各种复杂关系,提供额外的洞察力和识别否则将不会被注意的重要模式。
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在过去的二十年中,我们目睹了以图形或网络形式构建的有价值的大数据的大幅增长。为了将传统的机器学习和数据分析技术应用于此类数据,有必要将图形转换为基于矢量的表示,以保留图形最重要的结构属性。为此,文献中已经提出了大量的图形嵌入方法。它们中的大多数产生了适用于各种应用的通用嵌入,例如节点聚类,节点分类,图形可视化和链接预测。在本文中,我们提出了两个新的图形嵌入算法,这些算法是基于专门为节点分类问题设计的随机步道。已设计算法的随机步行采样策略旨在特别注意集线器 - 高度节点,这些节点在大规模图中具有最关键的作用。通过分析对现实世界网络嵌入的三种分类算法的分类性能,对所提出的方法进行实验评估。获得的结果表明,与当前最流行的随机步行方法相比,我们的方法可大大提高所检查分类器的预测能力(NODE2VEC)。
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Graphs are ubiquitous in nature and can therefore serve as models for many practical but also theoretical problems. For this purpose, they can be defined as many different types which suitably reflect the individual contexts of the represented problem. To address cutting-edge problems based on graph data, the research field of Graph Neural Networks (GNNs) has emerged. Despite the field's youth and the speed at which new models are developed, many recent surveys have been published to keep track of them. Nevertheless, it has not yet been gathered which GNN can process what kind of graph types. In this survey, we give a detailed overview of already existing GNNs and, unlike previous surveys, categorize them according to their ability to handle different graph types and properties. We consider GNNs operating on static and dynamic graphs of different structural constitutions, with or without node or edge attributes. Moreover, we distinguish between GNN models for discrete-time or continuous-time dynamic graphs and group the models according to their architecture. We find that there are still graph types that are not or only rarely covered by existing GNN models. We point out where models are missing and give potential reasons for their absence.
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