资源描述框架(RDF)是用于描述元数据的框架,例如网络上资源的属性和关系。 RDF图形的机器学习任务采用三种方法:(i)支持向量机(SVM)与RDF图形内核,(ii)RDF图嵌入,和(iii)关系图卷积网络。在本文中,我们提出了一种新颖的特征向量(称为跳过向量),其通过提取相邻边缘和节点的各种组合来表示RDF图中的每个资源的一些特征。为了使跳过向量低维,我们基于每个特征的信息增益比选择分类任务的重要特征。可以通过将每个资源的低维跳过向量应用于传统的机器学习算法,例如SVMS,K最近邻居方法,神经网络,随机林和Adaboost来执行分类任务。在我们的RDF数据的评估实验中,如Wikidata,DBPedia和Yago,我们将我们的方法与SVM中的RDF图形内核进行比较。我们还将我们的方法与两种方法进行了比较:RDF图形嵌入式,如RDF2VEC和AIFB,娇象,BGS和AM基准测试的RDF2VEC和关系图卷积网络。
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在过去十年中,图形内核引起了很多关注,并在结构化数据上发展成为一种快速发展的学习分支。在过去的20年中,该领域发生的相当大的研究活动导致开发数十个图形内核,每个图形内核都对焦于图形的特定结构性质。图形内核已成功地成功地在广泛的域中,从社交网络到生物信息学。本调查的目标是提供图形内核的文献的统一视图。特别是,我们概述了各种图形内核。此外,我们对公共数据集的几个内核进行了实验评估,并提供了比较研究。最后,我们讨论图形内核的关键应用,并概述了一些仍有待解决的挑战。
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Knowledge graphs enable a wide variety of applications, including question answering and information retrieval. Despite the great effort invested in their creation and maintenance, even the largest (e.g., Yago, DBPedia or Wikidata) remain incomplete. We introduce Relational Graph Convolutional Networks (R-GCNs) and apply them to two standard knowledge base completion tasks: Link prediction (recovery of missing facts, i.e. subject-predicate-object triples) and entity classification (recovery of missing entity attributes). R-GCNs are related to a recent class of neural networks operating on graphs, and are developed specifically to deal with the highly multi-relational data characteristic of realistic knowledge bases. We demonstrate the effectiveness of R-GCNs as a stand-alone model for entity classification. We further show that factorization models for link prediction such as DistMult can be significantly improved by enriching them with an encoder model to accumulate evidence over multiple inference steps in the relational graph, demonstrating a large improvement of 29.8% on FB15k-237 over a decoder-only baseline. * Equal contribution.
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Various graph neural networks (GNNs) have been proposed to solve node classification tasks in machine learning for graph data. GNNs use the structural information of graph data by aggregating the features of neighboring nodes. However, they fail to directly characterize and leverage the structural information. In this paper, we propose multi-duplicated characterization of graph structures using information gain ratio (IGR) for GNNs (MSI-GNN), which enhances the performance of node classification by using an i-hop adjacency matrix as the structural information of the graph data. In MSI-GNN, the i-hop adjacency matrix is adaptively adjusted by two methods: (i) structural features in the matrix are selected based on the IGR, and (ii) the selected features in (i) for each node are duplicated and combined flexibly. In an experiment, we show that our MSI-GNN outperforms GCN, H2GCN, and GCNII in terms of average accuracies in benchmark graph datasets.
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Most graph neural network models rely on a particular message passing paradigm, where the idea is to iteratively propagate node representations of a graph to each node in the direct neighborhood. While very prominent, this paradigm leads to information propagation bottlenecks, as information is repeatedly compressed at intermediary node representations, which causes loss of information, making it practically impossible to gather meaningful signals from distant nodes. To address this issue, we propose shortest path message passing neural networks, where the node representations of a graph are propagated to each node in the shortest path neighborhoods. In this setting, nodes can directly communicate between each other even if they are not neighbors, breaking the information bottleneck and hence leading to more adequately learned representations. Theoretically, our framework generalizes message passing neural networks, resulting in provably more expressive models, and we show that some recent state-of-the-art models are special instances of this framework. Empirically, we verify the capacity of a basic model of this framework on dedicated synthetic experiments, and on real-world graph classification and regression benchmarks, and obtain state-of-the-art results.
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近年来,基于Weisfeiler-Leman算法的算法和神经架构,是一个众所周知的Graph同构问题的启发式问题,它成为具有图形和关系数据的机器学习的强大工具。在这里,我们全面概述了机器学习设置中的算法的使用,专注于监督的制度。我们讨论了理论背景,展示了如何将其用于监督的图形和节点表示学习,讨论最近的扩展,并概述算法的连接(置换 - )方面的神经结构。此外,我们概述了当前的应用和未来方向,以刺激进一步的研究。
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In this article, we propose a family of efficient kernels for large graphs with discrete node labels. Key to our method is a rapid feature extraction scheme based on the Weisfeiler-Lehman test of isomorphism on graphs. It maps the original graph to a sequence of graphs, whose node attributes capture topological and label information. A family of kernels can be defined based on this Weisfeiler-Lehman sequence of graphs, including a highly efficient kernel comparing subtree-like patterns. Its runtime scales only linearly in the number of edges of the graphs and the length of the Weisfeiler-Lehman graph sequence. In our experimental evaluation, our kernels outperform state-of-the-art graph kernels on several graph classification benchmark data sets in terms of accuracy and runtime. Our kernels open the door to large-scale applications of graph kernels in various disciplines such as computational biology and social network analysis.
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这篇综述的目的是将读者介绍到图表内,以将其应用于化学信息学中的分类问题。图内核是使我们能够推断分子的化学特性的功能,可以帮助您完成诸如寻找适合药物设计的化合物等任务。内核方法的使用只是一种特殊的两种方式量化了图之间的相似性。我们将讨论限制在这种方法上,尽管近年来已经出现了流行的替代方法,但最著名的是图形神经网络。
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外部知识(A.K.A.侧面信息)在零拍摄学习(ZSL)中起着关键作用,该角色旨在预测从未出现在训练数据中的看不见的类。已被广泛调查了几种外部知识,例如文本和属性,但他们独自受到不完整的语义。因此,一些最近的研究提出了由于其高度富有效力和代表知识的兼容性而使用知识图表(千克)。但是,ZSL社区仍然缺乏用于学习和比较不同外部知识设置和基于不同的KG的ZSL方法的标准基准。在本文中,我们提出了六个资源,涵盖了三个任务,即零拍摄图像分类(ZS-IMGC),零拍摄关系提取(ZS-RE)和零拍KG完成(ZS-KGC)。每个资源都有一个正常的zsl基准标记和包含从文本到属性的kg的kg,从关系知识到逻辑表达式。我们已清楚地介绍了这些资源,包括其建设,统计数据格式和使用情况W.r.t.不同的ZSL方法。更重要的是,我们进行了一项全面的基准研究,具有两个通用和最先进的方法,两种特定方法和一种可解释方法。我们讨论并比较了不同的ZSL范式W.R.T.不同的外部知识设置,并发现我们的资源具有开发更高级ZSL方法的巨大潜力,并为应用KGS进行增强机学习的更多解决方案。所有资源都可以在https://github.com/china-uk-zsl/resources_for_kzsl上获得。
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The goal of graph summarization is to represent large graphs in a structured and compact way. A graph summary based on equivalence classes preserves pre-defined features of a graph's vertex within a $k$-hop neighborhood such as the vertex labels and edge labels. Based on these neighborhood characteristics, the vertex is assigned to an equivalence class. The calculation of the assigned equivalence class must be a permutation invariant operation on the pre-defined features. This is achieved by sorting on the feature values, e. g., the edge labels, which is computationally expensive, and subsequently hashing the result. Graph Neural Networks (GNN) fulfill the permutation invariance requirement. We formulate the problem of graph summarization as a subgraph classification task on the root vertex of the $k$-hop neighborhood. We adapt different GNN architectures, both based on the popular message-passing protocol and alternative approaches, to perform the structural graph summarization task. We compare different GNNs with a standard multi-layer perceptron (MLP) and Bloom filter as non-neural method. For our experiments, we consider four popular graph summary models on a large web graph. This resembles challenging multi-class vertex classification tasks with the numbers of classes ranging from $576$ to multiple hundreds of thousands. Our results show that the performance of GNNs are close to each other. In three out of four experiments, the non-message-passing GraphMLP model outperforms the other GNNs. The performance of the standard MLP is extraordinary good, especially in the presence of many classes. Finally, the Bloom filter outperforms all neural architectures by a large margin, except for the dataset with the fewest number of $576$ classes.
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事实证明,信息提取方法可有效从结构化或非结构化数据中提取三重。以(头部实体,关系,尾部实体)形式组织这样的三元组的组织称为知识图(kgs)。当前的大多数知识图都是不完整的。为了在下游任务中使用kgs,希望预测kgs中缺少链接。最近,通过将实体和关系嵌入到低维的矢量空间中,旨在根据先前访问的三元组来预测三元组,从而对KGS表示不同的方法。根据如何独立或依赖对三元组进行处理,我们将知识图完成的任务分为传统和图形神经网络表示学习,并更详细地讨论它们。在传统的方法中,每个三重三倍将独立处理,并在基于GNN的方法中进行处理,三倍也考虑了他们的当地社区。查看全文
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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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Low-dimensional embeddings of nodes in large graphs have proved extremely useful in a variety of prediction tasks, from content recommendation to identifying protein functions. However, most existing approaches require that all nodes in the graph are present during training of the embeddings; these previous approaches are inherently transductive and do not naturally generalize to unseen nodes. Here we present GraphSAGE, a general inductive framework that leverages node feature information (e.g., text attributes) to efficiently generate node embeddings for previously unseen data. Instead of training individual embeddings for each node, we learn a function that generates embeddings by sampling and aggregating features from a node's local neighborhood. Our algorithm outperforms strong baselines on three inductive node-classification benchmarks: we classify the category of unseen nodes in evolving information graphs based on citation and Reddit post data, and we show that our algorithm generalizes to completely unseen graphs using a multi-graph dataset of protein-protein interactions. * The two first authors made equal contributions. 1 While it is common to refer to these data structures as social or biological networks, we use the term graph to avoid ambiguity with neural network terminology.
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Relational machine learning studies methods for the statistical analysis of relational, or graph-structured, data. In this paper, we provide a review of how such statistical models can be "trained" on large knowledge graphs, and then used to predict new facts about the world (which is equivalent to predicting new edges in the graph). In particular, we discuss two fundamentally different kinds of statistical relational models, both of which can scale to massive datasets. The first is based on latent feature models such as tensor factorization and multiway neural networks. The second is based on mining observable patterns in the graph. We also show how to combine these latent and observable models to get improved modeling power at decreased computational cost. Finally, we discuss how such statistical models of graphs can be combined with text-based information extraction methods for automatically constructing knowledge graphs from the Web. To this end, we also discuss Google's Knowledge Vault project as an example of such combination.
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图形神经网络(GNNS)在学习归属图中显示了很大的力量。但是,GNNS从源节点利用遥控器的信息仍然是一个挑战。此外,常规GNN要求将图形属性作为输入,因此它们无法应用于纯图。在论文中,我们提出了名为G-GNNS(GNN的全局信息)的新模型来解决上述限制。首先,通过无监督的预训练获得每个节点的全局结构和属性特征,其保留与节点相关联的全局信息。然后,使用全局功能和原始网络属性,我们提出了一个并行GNN的并行框架来了解这些功能的不同方面。所提出的学习方法可以应用于普通图和归属图。广泛的实验表明,G-GNNS可以在三个标准评估图上优于其他最先进的模型。特别是,我们的方法在学习归属图表时建立了Cora(84.31 \%)和PubMed(80.95 \%)的新基准记录。
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资源说明框架(RDF)和属性图(PG)是表示,存储和查询图数据的两个最常用的数据模型。我们提出了表达推理图存储(ERGS) - 构建在Janusgraph(属性图存储)顶部的图存储,该图还允许存储和查询RDF数据集。首先,我们描述了如何将RDF数据转换为属性图表示,然后描述将SPARQL查询转换为一系列Gremlin遍历的查询翻译模块。因此,开发的转换器和翻译器可以允许任何Apache TinkerPop符合图形数据库存储和查询RDF数据集。我们证明了使用JanusGraph作为基本属性图存储的建议方法的有效性,并将其性能与标准RDF系统进行比较。
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大多数知识图嵌入技术将实体和谓词视为单独的嵌入矩阵,使用聚合函数来构建输入三重的表示。但是,这些聚集是有损的,即它们没有捕获原始三元组的语义,例如谓词中包含的信息。为了消除这些缺点,当前方法从头开始学习三重嵌入,而无需利用预训练模型的实体和谓词嵌入。在本文中,我们通过从预训练的知识图嵌入中创建弱监督信号来设计一种新型的微调方法来学习三重嵌入。我们开发了一种从知识图中自动采样三联的方法,并从预训练的嵌入模型中估算了它们的成对相似性。然后将这些成对的相似性得分馈送到类似暹罗的神经结构中,以微调三重表示。我们在两个广泛研究的知识图上评估了所提出的方法,并在三重分类和三重聚类任务上显示出对其他最先进的三重嵌入方法的一致改进。
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由Hong和Pavlic(2021)引入的单隐式层随机加权特征网络(RWFN)被开发为关系学习任务的神经张量网络方法的替代方案。其相对较小的占地面积结合使用了两个随机输入投影 - 一种昆虫 - 脑激发的输入表示和随机傅里叶特征 - 允许它以相对较低的培训成本实现有关关系的丰富表现力。特别是,当红和帕德奇比较RWFN到逻辑张量网络(LTNS)进行语义图像解释(SII)任务以提取图像的结构化语义描述,他们表明,两个隐藏的RWFN集成更好地捕获输入之间的关系具有更快的培训过程,即使它使用了更少的学习参数。在本文中,我们使用RWFN来执行视觉关系检测(VRD)任务,这些任务是更具挑战性的SII任务。零拍摄学习方法与RWFN一起使用,可以利用与其他所见关系和背景知识的相似性 - 以对象,关系和对象之间的逻辑约束表示 - 实现能够预测未出现在培训中的三维群体放。在视觉关系数据集上的实验,用于比较RWFN和LTNS之间的性能,其中一个领先的统计关系学习框架之一,显示RWFNS以谓词检测任务的销售胜过LTNS,同时使用较少数量的适应性参数(1:56比率)。此外,即使RWFNS的空间复杂性远小于LTNS(1:27比率),RWFN表示的背景技术也可用于减轻训练集的不完整性。
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图形内核是历史上最广泛使用的图形分类任务的技术。然而,由于图的手工制作的组合特征,这些方法具有有限的性能。近年来,由于其性能卓越,图形神经网络(GNNS)已成为与下游图形相关任务的最先进的方法。大多数GNN基于消息传递神经网络(MPNN)框架。然而,最近的研究表明,MPNN不能超过Weisfeiler-Lehman(WL)算法在图形同构术中的力量。为了解决现有图形内核和GNN方法的限制,在本文中,我们提出了一种新的GNN框架,称为\ Texit {内核图形神经网络}(Kernnns),该框架将图形内核集成到GNN的消息传递过程中。通过卷积神经网络(CNNS)中的卷积滤波器的启发,KERGNNS采用可训练的隐藏图作为绘图过滤器,该绘图过滤器与子图组合以使用图形内核更新节点嵌入式。此外,我们表明MPNN可以被视为Kergnns的特殊情况。我们将Kergnns应用于多个与图形相关的任务,并使用交叉验证来与基准进行公平比较。我们表明,与现有的现有方法相比,我们的方法达到了竞争性能,证明了增加GNN的表现能力的可能性。我们还表明,KERGNNS中的训练有素的图形过滤器可以揭示数据集的本地图形结构,与传统GNN模型相比,显着提高了模型解释性。
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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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