现代神经影像学技术,例如扩散张量成像(DTI)和功能性磁共振成像(fMRI),使我们能够将人脑建模为脑网络或连接组。捕获大脑网络的结构信息和分层模式对于理解大脑功能和疾病状态至关重要。最近,图形神经网络(GNN)的有前途的网络表示能力促使许多基于GNN的方法用于脑网络分析。具体而言,这些方法应用功能聚合和全局池来将大脑网络实例转换为有意义的低维表示,用于下游大脑网络分析任务。但是,现有的基于GNN的方法通常忽略了不同受试者的大脑网络可能需要各种聚合迭代,并将GNN与固定数量的层一起学习所有大脑网络。因此,如何完全释放GNN促进大脑网络分析的潜力仍然是不平凡的。为了解决这个问题,我们提出了一个新颖的大脑网络表示框架,即BN-GNN,该框架搜索每个大脑网络的最佳GNN体系结构。具体而言,BN-GNN使用深度加固学习(DRL)来训练元派利,以自动确定给定脑网络所需的最佳特征聚合数(反映在GNN层的数量中)。在八个现实世界大脑网络数据集上进行的广泛实验表明,我们提出的BN-GNN提高了传统GNN在不同大脑网络分析任务上的性能。
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Graph mining tasks arise from many different application domains, ranging from social networks, transportation to E-commerce, etc., which have been receiving great attention from the theoretical and algorithmic design communities in recent years, and there has been some pioneering work employing the research-rich Reinforcement Learning (RL) techniques to address graph data mining tasks. However, these graph mining methods and RL models are dispersed in different research areas, which makes it hard to compare them. In this survey, we provide a comprehensive overview of RL and graph mining methods and generalize these methods to Graph Reinforcement Learning (GRL) as a unified formulation. We further discuss the applications of GRL methods across various domains and summarize the method descriptions, open-source codes, and benchmark datasets of GRL methods. Furthermore, we propose important directions and challenges to be solved in the future. As far as we know, this is the latest work on a comprehensive survey of GRL, this work provides a global view and a learning resource for scholars. In addition, we create an online open-source for both interested scholars who want to enter this rapidly developing domain and experts who would like to compare GRL methods.
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社交机器人被称为社交网络上的自动帐户,这些帐户试图像人类一样行事。尽管图形神经网络(GNNS)已大量应用于社会机器人检测领域,但大量的领域专业知识和先验知识大量参与了最先进的方法,以设计专门的神经网络体系结构,以设计特定的神经网络体系结构。分类任务。但是,在模型设计中涉及超大的节点和网络层,通常会导致过度平滑的问题和缺乏嵌入歧视。在本文中,我们提出了罗斯加斯(Rosgas),这是一种新颖的加强和自我监督的GNN Architecture搜索框架,以适应性地指出了最合适的多跳跃社区和GNN体系结构中的层数。更具体地说,我们将社交机器人检测问题视为以用户为中心的子图嵌入和分类任务。我们利用异构信息网络来通过利用帐户元数据,关系,行为特征和内容功能来展示用户连接。 Rosgas使用多代理的深钢筋学习(RL)机制来导航最佳邻域和网络层的搜索,以分别学习每个目标用户的子图嵌入。开发了一种用于加速RL训练过程的最接近的邻居机制,Rosgas可以借助自我监督的学习来学习更多的判别子图。 5个Twitter数据集的实验表明,Rosgas在准确性,训练效率和稳定性方面优于最先进的方法,并且在处理看不见的样本时具有更好的概括。
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Mapping the connectome of the human brain using structural or functional connectivity has become one of the most pervasive paradigms for neuroimaging analysis. Recently, Graph Neural Networks (GNNs) motivated from geometric deep learning have attracted broad interest due to their established power for modeling complex networked data. Despite their superior performance in many fields, there has not yet been a systematic study of how to design effective GNNs for brain network analysis. To bridge this gap, we present BrainGB, a benchmark for brain network analysis with GNNs. BrainGB standardizes the process by (1) summarizing brain network construction pipelines for both functional and structural neuroimaging modalities and (2) modularizing the implementation of GNN designs. We conduct extensive experiments on datasets across cohorts and modalities and recommend a set of general recipes for effective GNN designs on brain networks. To support open and reproducible research on GNN-based brain network analysis, we host the BrainGB website at https://braingb.us with models, tutorials, examples, as well as an out-of-box Python package. We hope that this work will provide useful empirical evidence and offer insights for future research in this novel and promising direction.
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深度强化学习(DRL)赋予了各种人工智能领域,包括模式识别,机器人技术,推荐系统和游戏。同样,图神经网络(GNN)也证明了它们在图形结构数据的监督学习方面的出色表现。最近,GNN与DRL用于图形结构环境的融合引起了很多关注。本文对这些混合动力作品进行了全面评论。这些作品可以分为两类:(1)算法增强,其中DRL和GNN相互补充以获得更好的实用性; (2)特定于应用程序的增强,其中DRL和GNN相互支持。这种融合有效地解决了工程和生命科学方面的各种复杂问题。基于审查,我们进一步分析了融合这两个领域的适用性和好处,尤其是在提高通用性和降低计算复杂性方面。最后,集成DRL和GNN的关键挑战以及潜在的未来研究方向被突出显示,这将引起更广泛的机器学习社区的关注。
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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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无创医学神经影像学已经对大脑连通性产生了许多发现。开发了几种实质技术绘制形态,结构和功能性脑连接性,以创建人脑中神经元活动的全面路线图。依靠其非欧国人数据类型,图形神经网络(GNN)提供了一种学习深图结构的巧妙方法,并且它正在迅速成为最先进的方法,从而导致各种网络神经科学任务的性能增强。在这里,我们回顾了当前基于GNN的方法,突出了它们在与脑图有关的几种应用中使用的方式,例如缺失的脑图合成和疾病分类。最后,我们通过绘制了通往网络神经科学领域中更好地应用GNN模型在神经系统障碍诊断和人群图整合中的路径。我们工作中引用的论文列表可在https://github.com/basiralab/gnns-inns-intwork-neuroscience上找到。
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大脑网络将大脑区域之间的复杂连接性描述为图形结构,这为研究脑连接素提供了强大的手段。近年来,图形神经网络已成为使用结构化数据的普遍学习范式。但是,由于数据获取的成本相对较高,大多数大脑网络数据集的样本量受到限制,这阻碍了足够的培训中的深度学习模型。受元学习的启发,该论文以有限的培训示例快速学习新概念,研究了在跨数据库中分析脑连接组的数据有效培训策略。具体而言,我们建议在大型样本大小的数据集上进行元训练模型,并将知识转移到小数据集中。此外,我们还探索了两种面向脑网络的设计,包括Atlas转换和自适应任务重新启动。与其他训练前策略相比,我们的基于元学习的方法实现了更高和稳定的性能,这证明了我们提出的解决方案的有效性。该框架还能够以数据驱动的方式获得有关数据集和疾病之间相似之处的新见解。
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图表可以模拟实体之间的复杂交互,它在许多重要的应用程序中自然出现。这些应用程序通常可以投入到标准图形学习任务中,其中关键步骤是学习低维图表示。图形神经网络(GNN)目前是嵌入方法中最受欢迎的模型。然而,邻域聚合范例中的标准GNN患有区分\ EMPH {高阶}图形结构的有限辨别力,而不是\ EMPH {低位}结构。为了捕获高阶结构,研究人员求助于主题和开发的基于主题的GNN。然而,现有的基于主基的GNN仍然仍然遭受较少的辨别力的高阶结构。为了克服上述局限性,我们提出了一个新颖的框架,以更好地捕获高阶结构的新框架,铰接于我们所提出的主题冗余最小化操作员和注射主题组合的新颖框架。首先,MGNN生成一组节点表示W.R.T.每个主题。下一阶段是我们在图案中提出的冗余最小化,该主题在彼此相互比较并蒸馏出每个主题的特征。最后,MGNN通过组合来自不同图案的多个表示来执行节点表示的更新。特别地,为了增强鉴别的功率,MGNN利用重新注射功能来组合表示的函数w.r.t.不同的主题。我们进一步表明,我们的拟议体系结构增加了GNN的表现力,具有理论分析。我们展示了MGNN在节点分类和图形分类任务上的七个公共基准上表现出最先进的方法。
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图表神经网络(GNN)基于故障诊断(FD)近年来收到了越来越多的关注,因为来自来自多个应用域的数据可以有利地表示为图。实际上,与传统的FD方法相比,这种特殊的代表性表格导致了卓越的性能。在本次审查中,给出了GNN,对故障诊断领域的潜在应用以及未来观点的简单介绍。首先,通过专注于它们的数据表示,即时间序列,图像和图形,回顾基于神经网络的FD方法。其次,引入了GNN的基本原则和主要架构,注意了图形卷积网络,图注意网络,图形样本和聚合,图形自动编码器和空间 - 时间图卷积网络。第三,通过详细实验验证基于GNN的最相关的故障诊断方法,结论是基于GNN的方法可以实现良好的故障诊断性能。最后,提供了讨论和未来的挑战。
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Graph classification is an important area in both modern research and industry. Multiple applications, especially in chemistry and novel drug discovery, encourage rapid development of machine learning models in this area. To keep up with the pace of new research, proper experimental design, fair evaluation, and independent benchmarks are essential. Design of strong baselines is an indispensable element of such works. In this thesis, we explore multiple approaches to graph classification. We focus on Graph Neural Networks (GNNs), which emerged as a de facto standard deep learning technique for graph representation learning. Classical approaches, such as graph descriptors and molecular fingerprints, are also addressed. We design fair evaluation experimental protocol and choose proper datasets collection. This allows us to perform numerous experiments and rigorously analyze modern approaches. We arrive to many conclusions, which shed new light on performance and quality of novel algorithms. We investigate application of Jumping Knowledge GNN architecture to graph classification, which proves to be an efficient tool for improving base graph neural network architectures. Multiple improvements to baseline models are also proposed and experimentally verified, which constitutes an important contribution to the field of fair model comparison.
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在大脑中找到适当的动态活动的适当表示对于许多下游应用至关重要。由于其高度动态的性质,暂时平均fMRI(功能磁共振成像)只能提供狭窄的脑活动视图。以前的作品缺乏学习和解释大脑体系结构中潜在动态的能力。本文构建了一个有效的图形神经网络模型,该模型均包含了从DWI(扩散加权成像)获得的区域映射的fMRI序列和结构连接性作为输入。我们通过学习样品水平的自适应邻接矩阵并进行新型多分辨率内群平滑来发现潜在大脑动力学的良好表示。我们还将输入归因于具有集成梯度的输入,这使我们能够针对每个任务推断(1)高度涉及的大脑连接和子网络,(2)成像序列的时间键帧,这些成像序列表征了任务,以及(3)歧视单个主体的子网络。这种识别特征在异质任务和个人中表征信号状态的关键子网的能力对神经科学和其他科学领域至关重要。广泛的实验和消融研究表明,我们提出的方法在空间 - 周期性图信号建模中的优越性和效率,具有对脑动力学的深刻解释。
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Graph Neural Networks (GNNs) have attracted increasing attention in recent years and have achieved excellent performance in semi-supervised node classification tasks. The success of most GNNs relies on one fundamental assumption, i.e., the original graph structure data is available. However, recent studies have shown that GNNs are vulnerable to the complex underlying structure of the graph, making it necessary to learn comprehensive and robust graph structures for downstream tasks, rather than relying only on the raw graph structure. In light of this, we seek to learn optimal graph structures for downstream tasks and propose a novel framework for semi-supervised classification. Specifically, based on the structural context information of graph and node representations, we encode the complex interactions in semantics and generate semantic graphs to preserve the global structure. Moreover, we develop a novel multi-measure attention layer to optimize the similarity rather than prescribing it a priori, so that the similarity can be adaptively evaluated by integrating measures. These graphs are fused and optimized together with GNN towards semi-supervised classification objective. Extensive experiments and ablation studies on six real-world datasets clearly demonstrate the effectiveness of our proposed model and the contribution of each component.
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Influence Maximization (IM) is a classical combinatorial optimization problem, which can be widely used in mobile networks, social computing, and recommendation systems. It aims at selecting a small number of users such that maximizing the influence spread across the online social network. Because of its potential commercial and academic value, there are a lot of researchers focusing on studying the IM problem from different perspectives. The main challenge comes from the NP-hardness of the IM problem and \#P-hardness of estimating the influence spread, thus traditional algorithms for overcoming them can be categorized into two classes: heuristic algorithms and approximation algorithms. However, there is no theoretical guarantee for heuristic algorithms, and the theoretical design is close to the limit. Therefore, it is almost impossible to further optimize and improve their performance. With the rapid development of artificial intelligence, the technology based on Machine Learning (ML) has achieved remarkable achievements in many fields. In view of this, in recent years, a number of new methods have emerged to solve combinatorial optimization problems by using ML-based techniques. These methods have the advantages of fast solving speed and strong generalization ability to unknown graphs, which provide a brand-new direction for solving combinatorial optimization problems. Therefore, we abandon the traditional algorithms based on iterative search and review the recent development of ML-based methods, especially Deep Reinforcement Learning, to solve the IM problem and other variants in social networks. We focus on summarizing the relevant background knowledge, basic principles, common methods, and applied research. Finally, the challenges that need to be solved urgently in future IM research are pointed out.
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近年来,图表表示学习越来越多地引起了越来越长的关注,特别是为了在节点和图表水平上学习对分类和建议任务的低维嵌入。为了能够在现实世界中的大规模图形数据上学习表示,许多研究专注于开发不同的抽样策略,以方便培训过程。这里,我们提出了一种自适应图策略驱动的采样模型(GPS),其中通过自适应相关计算实现了本地邻域中每个节点的影响。具体地,邻居的选择是由自适应策略算法指导的,直接贡献到消息聚合,节点嵌入更新和图级读出步骤。然后,我们从各种角度对图表分类任务进行全面的实验。我们所提出的模型在几个重要的基准测试中优于现有的3%-8%,实现了现实世界数据集的最先进的性能。
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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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注意机制使图形神经网络(GNN)能够学习目标节点与其单跳邻居之间的注意力权重,从而进一步提高性能。但是,大多数现有的GNN都针对均匀图,其中每一层只能汇总单跳邻居的信息。堆叠多层网络引入了相当大的噪音,并且很容易导致过度平滑。我们在这里提出了一种多跃波异质邻域信息融合图表示方法(MHNF)。具体而言,我们提出了一个混合元自动提取模型,以有效提取多ihop混合邻居。然后,我们制定了一个跳级的异质信息聚合模型,该模型在同一混合Metapath中选择性地汇总了不同的跳跃邻域信息。最后,构建了分层语义注意融合模型(HSAF),该模型可以有效地整合不同的互动和不同的路径邻域信息。以这种方式,本文解决了汇总MultiHop邻里信息和学习目标任务的混合元数据的问题。这减轻了手动指定Metapaths的限制。此外,HSAF可以提取Metapaths的内部节点信息,并更好地整合存在不同级别的语义信息。真实数据集的实验结果表明,MHNF在最先进的基准中取得了最佳或竞争性能,仅1/10〜1/100参数和计算预算。我们的代码可在https://github.com/phd-lanyu/mhnf上公开获取。
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图形神经网络(GNN)在学习强大的节点表示中显示了令人信服的性能,这些表现在保留节点属性和图形结构信息的强大节点表示中。然而,许多GNNS在设计有更深的网络结构或手柄大小的图形时遇到有效性和效率的问题。已经提出了几种采样算法来改善和加速GNN的培训,但他们忽略了解GNN性能增益的来源。图表数据中的信息的测量可以帮助采样算法来保持高价值信息,同时消除冗余信息甚至噪声。在本文中,我们提出了一种用于GNN的公制引导(MEGUIDE)子图学习框架。 MEGUIDE采用两种新颖的度量:功能平滑和连接失效距离,以指导子图采样和迷你批次的培训。功能平滑度专为分析节点的特征而才能保留最有价值的信息,而连接失败距离可以测量结构信息以控制子图的大小。我们展示了MEGUIDE在多个数据集上培训各种GNN的有效性和效率。
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知识蒸馏(KD)证明了其有效性,可以提高图形神经网络(GNN)的性能,其目标是将知识从更深的教师gnn蒸馏成较浅的学生GNN。但是,由于众所周知的过度参数和过度光滑的问题,实际上很难培训令人满意的教师GNN,从而导致实际应用中的知识转移无效。在本文中,我们通过对GNN的加强学习(称为FreeKD)提出了第一个自由方向知识蒸馏框架,而这不再需要提供更深入的良好优化的教师GNN。我们工作的核心思想是协作建立两个较浅的GNN,以通过以层次结构方式通过加强学习来交流知识。正如我们观察到的一个典型的GNN模型在训练过程中通常在不同节点的表现更好,更差的表现,我们设计了一种动态和自由方向的知识转移策略,该策略由两个级别的动作组成:1)节点级别的动作决定了知识的方向。两个网络的相应节点之间的传输;然后2)结构级的动作确定了要传播的节点级别生成的局部结构。从本质上讲,我们的FreeKD是一个一般且原则性的框架,可以自然与不同架构的GNN兼容。在五个基准数据集上进行的广泛实验表明,我们的FreeKD在很大的边距上优于两个基本GNN,并显示了其对各种GNN的功效。更令人惊讶的是,我们的FreeKD比传统的KD算法具有可比性甚至更好的性能,这些KD算法将知识从更深,更强大的教师GNN中提取。
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随着传感技术的进步,多元时间序列分类(MTSC)最近受到了相当大的关注。基于深度学习的MTSC技术主要依赖于卷积或经常性神经网络,主要涉及单时间序列的时间依赖性。结果,他们努力直接在多变量变量中表达成对依赖性。此外,基于图形神经网络(GNNS)的当前空间 - 时间建模(例如,图形分类)方法本质上是平的,并且不能以分层方式聚合集线器数据。为了解决这些限制,我们提出了一种基于新的图形汇集框架MTPOOL,以获得MTS的表现力全球表示。我们首先通过采用通过图形结构学习模块的相互作用来将MTS切片转换为曲线图,并通过时间卷积模块获得空间 - 时间图节点特征。为了获得全局图形级表示,我们设计了基于“编码器 - 解码器”的变形图池池模块,用于为群集分配创建自适应质心。然后我们将GNN和我们所提出的变分图层汇集层组合用于联合图表示学习和图形粗糙化,之后该图逐渐赋予一个节点。最后,可差异化的分类器将此粗糙的表示来获取最终预测的类。 10个基准数据集的实验表明MTPOOL优于MTSC任务中最先进的策略。
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