薄文件借款人是由于缺乏信用历史而不确定的信誉评估的客户;许多研究人员使用借款人的关系和交互网络以图形的形式作为替代数据源来解决这个问题。包含网络数据传统上由手工制作的特征工程制作,并且最近,图形神经网络已成为替代方案,但它仍然没有改善传统方法的性能。在这里,我们介绍一个框架来通过混合几个图形表示学习方法来改进信用评分模型:功能工程,图形嵌入和图形神经网络。我们堆叠了他们的产出以在这种方法中产生单一分数。我们使用独特的多源数据集进行了验证了此框架,该数据集具有与拉丁美洲国家的整个人口的关系和信用历史,将其应用于信用风险模型,应用和行为,针对个人和公司。我们的结果表明,图表表示学习方法应用作补充,并且这些方法不应被视为自给自足的方法,就像目前所做的那样。在AUC和KS方面,我们提升了统计表现,优于传统方法。在公司贷款中,在收益要高得多的情况下,它证实,评估了一个不道实的公司,不能仅考虑其特征。这些公司与业主,供应商,客户和其他公司互动的商业生态系统提供了新颖的知识,使金融机构能够提高信誉评估。我们的结果让我们知道何时以及哪些组使用图表数据以及对性能的影响。它们还展示了图形数据的巨大价值,主要是为了帮助公司的银行业务。
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Credit scoring models are the primary instrument used by financial institutions to manage credit risk. The scarcity of research on behavioral scoring is due to the difficult data access. Financial institutions have to maintain the privacy and security of borrowers' information refrain them from collaborating in research initiatives. In this work, we present a methodology that allows us to evaluate the performance of models trained with synthetic data when they are applied to real-world data. Our results show that synthetic data quality is increasingly poor when the number of attributes increases. However, creditworthiness assessment models trained with synthetic data show a reduction of 3\% of AUC and 6\% of KS when compared with models trained with real data. These results have a significant impact since they encourage credit risk investigation from synthetic data, making it possible to maintain borrowers' privacy and to address problems that until now have been hampered by the availability of information.
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在许多研究中已经表明,考虑相关股票数据预测股票价格变动的重要性,但是,用于建模,嵌入和分析相互关联股票行为的先进图形技术尚未被广泛利用,以预测股票价格变动。该领域的主要挑战是找到一种建模任意股票之间现有关系的方法,并利用这种模型来改善这些股票的预测绩效。该领域中的大多数现有方法都取决于基本的图形分析技术,预测能力有限,并且缺乏通用性和灵活性。在本文中,我们介绍了一个名为GCNET的新颖框架,该框架将任意股票之间的关系建模为称为“影响网络”的图形结构,并使用一组基于历史的预测模型来推断出股票子集的合理初始标签图中的节点。最后,GCNET使用图形卷积网络算法来分析此部分标记的图形,并预测图中每个库存的下一个运动价格方向。 GCNET是一个一般预测框架,可以根据其历史数据来预测相互作用股票的价格波动。我们对纳斯达克指数一组股票的实验和评估表明,GCNET在准确性和MCC测量方面显着提高了SOTA的性能。
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保持个人特征和复杂的关系,广泛利用和研究了图表数据。通过更新和聚合节点的表示,能够捕获结构信息,图形神经网络(GNN)模型正在获得普及。在财务背景下,该图是基于实际数据构建的,这导致复杂的图形结构,因此需要复杂的方法。在这项工作中,我们在最近的财务环境中对GNN模型进行了全面的审查。我们首先将普通使用的财务图分类并总结每个节点的功能处理步骤。然后,我们总结了每个地图类型的GNN方法,每个区域的应用,并提出一些潜在的研究领域。
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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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人工智能(AI)使机器能够从人类经验中学习,适应新的输入,并执行人类的人类任务。 AI正在迅速发展,从过程自动化到认知增强任务和智能流程/数据分析的方式转换业务方式。然而,人类用户的主要挑战是理解和适当地信任AI算法和方法的结果。在本文中,为了解决这一挑战,我们研究并分析了最近在解释的人工智能(XAI)方法和工具中所做的最新工作。我们介绍了一种新颖的XAI进程,便于生产可解释的模型,同时保持高水平的学习性能。我们提出了一种基于互动的证据方法,以帮助人类用户理解和信任启用AI的算法创建的结果和输出。我们在银行域中采用典型方案进行分析客户交易。我们开发数字仪表板以促进与算法的互动结果,并讨论如何提出的XAI方法如何显着提高数据科学家对理解启用AI的算法结果的置信度。
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当没有足够的数据来证实客户的身份时,身份盗窃是信贷贷方的主要问题。在超级应用程序中,包含许多不同服务的大型数字平台,此问题更为相关;在一个分支中丢失客户通常意味着在其他服务中丢失它们。在本文中,我们审查了超级应用程序信息,手机线数据和传统信用风险变量的特征级融合的有效性,以便早日检测身份盗窃信用卡欺诈。通过提出的框架,我们在使用投入是替代数据和传统信贷局数据融合的模型时实现了更好的性能,从而实现了0.81的ROC AUC评分。我们从信用贷方的数字平台数据库中评估我们的方法超过大约90,000个用户。评估是使用传统的ML指标进行的,但金融成本也是如此。
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情绪预测在心理健康和情绪感知计算中起着至关重要的作用。情绪的复杂性质是由于其对一个人的生理健康,精神状态和周围环境的依赖而产生的,这使其预测一项艰巨的任务。在这项工作中,我们利用移动传感数据来预测幸福和压力。除了一个人的生理特征外,我们还通过天气和社交网络纳入了环境的影响。为此,我们利用电话数据来构建社交网络并开发机器学习体系结构,该架构从图形网络的多个用户中汇总信息,并将其与数据的时间动态集成在一起,以预测所有用户的情感。社交网络的构建不会在用户的EMA或数据收集方面产生额外的成本,也不会引起隐私问题。我们提出了一种自动化用户社交网络影响预测的架构,能够处理现实生活中社交网络的动态分布,从而使其可扩展到大规模网络。我们广泛的评估突出了社交网络集成提供的改进。我们进一步研究了图形拓扑对模型性能的影响。
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在本文中,我们研究了中途公司,即在市场资本化少于100亿美元的公开交易公司。在30年内使用美国中载公司的大型数据集,我们期望通过中期预测默认的概率术语结构,了解哪些数据源(即基本,市场或定价数据)对违约风险贡献最多。然而,现有方法通常要求来自不同时间段的数据首先聚合并转变为横截面特征,我们将问题框架作为多标签时间级分类问题。我们适应变压器模型,从自然语言处理领域发出的最先进的深度学习模型,以信用风险建模设置。我们还使用注意热图解释这些模型的预测。为了进一步优化模型,我们为多标签分类和新型多通道架构提供了一种自定义损耗功能,具有差异训练,使模型能够有效地使用所有输入数据。我们的结果表明,拟议的深度学习架构的卓越性能,导致传统模型的AUC(接收器运行特征曲线下的区域)提高了13%。我们还展示了如何使用特定于这些模型的福利方法生成不同数据源和时间关系的重要性排名。
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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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Pre-publication draft of a book to be published byMorgan & Claypool publishers. Unedited version released with permission. All relevant copyrights held by the author and publisher extend to this pre-publication draft.
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机器学习渗透到许多行业,这为公司带来了新的利益来源。然而,在人寿保险行业中,机器学习在实践中并未被广泛使用,因为在过去几年中,统计模型表明了它们的风险评估效率。因此,保险公司可能面临评估人工智能价值的困难。随着时间的流逝,专注于人寿保险行业的修改突出了将机器学习用于保险公司的利益以及通过释放数据价值带来的利益。本文回顾了传统的生存建模方法论,并通过机器学习技术扩展了它们。它指出了与常规机器学习模型的差异,并强调了特定实现在与机器学习模型家族中面对审查数据的重要性。在本文的补充中,已经开发了Python库。已经调整了不同的开源机器学习算法,以适应人寿保险数据的特殊性,即检查和截断。此类模型可以轻松地从该SCOR库中应用,以准确地模拟人寿保险风险。
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Anomaly analytics is a popular and vital task in various research contexts, which has been studied for several decades. At the same time, deep learning has shown its capacity in solving many graph-based tasks like, node classification, link prediction, and graph classification. Recently, many studies are extending graph learning models for solving anomaly analytics problems, resulting in beneficial advances in graph-based anomaly analytics techniques. In this survey, we provide a comprehensive overview of graph learning methods for anomaly analytics tasks. We classify them into four categories based on their model architectures, namely graph convolutional network (GCN), graph attention network (GAT), graph autoencoder (GAE), and other graph learning models. The differences between these methods are also compared in a systematic manner. Furthermore, we outline several graph-based anomaly analytics applications across various domains in the real world. Finally, we discuss five potential future research directions in this rapidly growing field.
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预测中小型企业(SME)的破产风险(SME)是金融机构在做出贷款时的重要一步。但是,金融和AI研究领域的现有研究倾向于仅考虑企业内风险或传染性风险,而忽略了它们的相互作用和组合效应。这项研究首次考虑了在破产预测中的风险及其共同影响。具体而言,我们首先根据其风险内学习的统计学意义企业风险指标提出了企业内风险编码器。然后,我们根据企业关系信息从企业知识图中提出了一个企业传染风险编码器,以进行其传染风险嵌入。特别是,传染风险编码器既包括新提出的高图神经网络和异质图神经网络,这些神经网络可以在两个不同方面建模传播风险,即基于超系统的常见风险因素和直接扩散的风险。为了评估该模型,我们收集了SME上的现实世界多源数据数据,并构建了一个名为SMESD的新型基准数据集。我们提供对数据集的开放访问权限,该数据集有望进一步促进财务风险分析的研究。针对十二个最先进的基线的SMESD实验证明了拟议模型对破产预测的有效性。
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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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即使机器学习算法已经在数据科学中发挥了重要作用,但许多当前方法对输入数据提出了不现实的假设。由于不兼容的数据格式,或数据集中的异质,分层或完全缺少的数据片段,因此很难应用此类方法。作为解决方案,我们提出了一个用于样本表示,模型定义和培训的多功能,统一的框架,称为“ Hmill”。我们深入审查框架构建和扩展的机器学习的多个范围范式。从理论上讲,为HMILL的关键组件的设计合理,我们将通用近似定理的扩展显示到框架中实现的模型所实现的所有功能的集合。本文还包含有关我们实施中技术和绩效改进的详细讨论,该讨论将在MIT许可下发布供下载。该框架的主要资产是其灵活性,它可以通过相同的工具对不同的现实世界数据源进行建模。除了单独观察到每个对象的一组属性的标准设置外,我们解释了如何在框架中实现表示整个对象系统的图表中的消息推断。为了支持我们的主张,我们使用框架解决了网络安全域的三个不同问题。第一种用例涉及来自原始网络观察结果的IoT设备识别。在第二个问题中,我们研究了如何使用以有向图表示的操作系统的快照可以对恶意二进制文件进行分类。最后提供的示例是通过网络中实体之间建模域黑名单扩展的任务。在所有三个问题中,基于建议的框架的解决方案可实现与专业方法相当的性能。
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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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We introduce the XPER (eXplainable PERformance) methodology to measure the specific contribution of the input features to the predictive or economic performance of a model. Our methodology offers several advantages. First, it is both model-agnostic and performance metric-agnostic. Second, XPER is theoretically founded as it is based on Shapley values. Third, the interpretation of the benchmark, which is inherent in any Shapley value decomposition, is meaningful in our context. Fourth, XPER is not plagued by model specification error, as it does not require re-estimating the model. Fifth, it can be implemented either at the model level or at the individual level. In an application based on auto loans, we find that performance can be explained by a surprisingly small number of features. XPER decompositions are rather stable across metrics, yet some feature contributions switch sign across metrics. Our analysis also shows that explaining model forecasts and model performance are two distinct tasks.
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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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大多数人类活动都需要在正式或非正式团队内部和跨部队进行合作。我们对团队所花费的合作努力与他们的表现有何关系的理解仍然是一个辩论问题。团队合作导致了一个高度相互联系的生态系统,这些生态系统可能是重叠的组件,其中与团队成员和其他团队进行互动执行任务。为了解决这个问题,我们提出了一个图形神经网络模型,旨在预测团队的性能,同时确定确定这种结果的驱动程序。特别是,该模型基于三个架构渠道:拓扑,中心性和上下文,它们捕获了不同因素可能塑造了团队的成功。我们赋予该模型具有两种注意机制,以提高模型性能并允许解释性。第一种机制允许查明团队内部的关键成员。第二种机制使我们能够量化三个驱动程序在确定结果绩效方面的贡献。我们在广泛的域上测试模型性能,其表现优于所考虑的大多数经典和神经基准。此外,我们包括专门设计的合成数据集,以验证该模型如何删除我们的模型胜过基线的预期属性。
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