SCN_GNN: A GNN-based fraud detection algorithm combining strong node and graph topology information

This paper addresses the critical challenge of fraud detection in medical insurance claims-a pervasive issue causing significant financial losses in healthcare-using Graph Neural Networks (GNNs). Given the intricate nature of healthcare data, traditional fraud detection methods do not inherently capture the complex relationships and patterns among different entities. We explore the potential of GNNs to effectively identify fraudulent claims by modeling the interactions among various entities-such as patients, healthcare providers, diagnoses, and services-as a heterogeneous graph. We employ two state-of-the-art heterogeneous GNN architectures, HINormer (Heterogeneous Information Network Transformer) and HybridGNN, along with a modified homogeneous GNN, RE-GraphSAGE (GraphSAGE "Graph Sample and Aggregate" with relation embeddings), adapted to handle the heterogeneity of healthcare data. The models are evaluated on real-world claims datasets of different sizes, comprising millions of medical activities. For the small-size claims dataset, the HINormer architecture followed by the RE-GraphSAGE architecture achieved the highest F-score (84% and 83%, respectively). For the medium-sized claims dataset, RE-GraphSAGE followed by HINormer achieved the highest F-score (84% and 81%, respectively), and for the large-size claims dataset, HINormer followed by RE-GraphSAGE achieved the highest F-score (82% and 79%, respectively). Additionally, we apply explainability techniques, namely GNNExplainer and PGExplainer, to provide insights into the models' decision-making processes and to examine their medical significance.

Semi-supervised node classification on graph-structured data has many applications such as fraud detection, fake account and review detection, user’s private attribute inference in social networks, and community detection. Various methods such as pairwise Markov Random Fields (pMRF) and graph neural networks were developed for semi-supervised node classification. pMRF is more efficient than graph neural networks. However, existing pMRF-based methods are less accurate than graph neural networks, due to a key limitation that they assume a heuristics-based constant edge potential for all edges. In this work, we aim to address the key limitation of existing pMRF-based methods. In particular, we propose to learn edge potentials for pMRF. Our evaluation results on various types of graph datasets show that our optimized pMRF-based method consistently outperforms existing graph neural networks in terms of both accuracy and efficiency. Our results highlight that previous work may have underestimated the power of pMRF for semi-supervised node classification.

Recently, Graph Neural Networks (GNNs) have been widely used for fraud detection. GNNs first generate node embedding by aggregating neighboring information under different relations, and then use the final node embedding to detect the node’s suspiciousness. However, traditional GNNs employing only a single type of aggregator fail to capture neighbor information from multiple perspectives and treating different relations equally inevitably weakens the semantic information of heterogeneous graphs. Meanwhile, expressive ability of GNNs is limited by using conventional concatenating or averaging operations to update the center node. Also, camouflaged entities could damage GNN-based models. To handle these problems, a novel heterogeneous GNN model called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Multiple Aggregators and Feature Interactions Network</i> (MAFI) is proposed in this paper to conduct fraud detection tasks. Concretely, multiple types of aggregators are applied on different relations to aggregate neighbor information and aggregator-level attention is utilized to learn the importance of different aggregators. Also, relation-level attention is leveraged to learn the importance of each relation. Besides, conventional update operations are replaced with vector-wise implicit and explicit feature interactions. Moreover, a trainable neighbor sampler is employed to filter camouflaged fraudsters. Comprehensive experiments on two real-world fraud datasets indicate that the proposed MAFI outperforms existing GNN-based fraud detectors.

Network representation learning is receiving increasing attention from scholars. Among them, methods based on graph neural networks have become particularly popular. However, most existing methods currently only focus on networks with a single type of relations. In the real world, networks contain a wealth of diverse information, with multiple types of relationships between nodes. In this paper, we propose a graph neural network-based multiplex network representation learning model (GNMRL). We model nodes within each layer of the multiplex network by aggregating neighbor information. Additionally, since nodes are influenced by different network layers, we integrate node interaction information across network layers. We conducted systematic experiments on four datasets, and the results show that GNMRL outperforms other comparison methods in both link prediction and node classification tasks.

The exponential growth of digital payment systems and electronic commerce has positioned credit card fraud as one of the most pressing challenges facing modern financial institutions. While traditional rule-based detection systems have demonstrated effectiveness in controlled environments, they exhibit fundamental limitations in adaptability when confronted with the dynamic and adversarial nature of contemporary fraud schemes. This comprehensive review examines the evolution and current state of machine learning approaches for credit card fraud detection, spanning from classical supervised learning algorithms to cutting-edge deep learning architectures and graph-based methodologies. This paper addresses critical challenges inherent in fraud detection, including extreme class imbalance (fraudulent transactions typically represent less than 1% of total volumes), concept drift caused by evolving fraud strategies, asymmetric misclassification costs, and real-time processing constraints. We systematically analyze supervised learning methods such as Logistic Regression, Decision Trees, Random Forests, Support Vector Machines, and Gradient Boosting Machines (XGBoost), alongside deep learning architectures including Artificial Neural Networks, Long Short-Term Memory (LSTM) networks, Convolutional Neural Networks, and hybrid CNN-LSTM models. A comparative analysis of existing studies from 2010 to 2025 reveals that ensemble methods and deep learning models consistently outperform traditional classifiers, with graph neural networks and attention-based architectures achieving state-of-the-art performance. Despite significant advancements, challenges related to model interpretability, adaptive learning in non-stationary environments, computational efficiency for real-time deployment, and data privacy compliance remain unresolved. This review identifies emerging research directions—including semi-supervised learning, adaptive feature selection, and explainable AI—as promising avenues for developing robust, scalable, and transparent fraud detection systems suitable for real-world financial environments.

BalancerGNN: Balancer Graph Neural Networks for imbalanced datasets: A case study on fraud detection

Motif-aware curriculum learning for node classification.

Insurance fraud represents a significant financial burden globally, with annual losses exceeding $200 billion across healthcare, auto, and life insurance sectors. Traditional rule-based fraud detection systems have proven inadequate against increasingly sophisticated fraudulent schemes, prompting widespread adoption of deep learning (DL) approaches. This comprehensive review systematically examines the application of DL techniques to insurance fraud detection, analyzing 57 peer-reviewed studies published between 2019 and 2025. We evaluate the effectiveness of various architectures including Convolutional Neural Networks (CNNs), Long Short-Term Memory networks (LSTMs), Graph Neural Networks (GNNs), and hybrid models across healthcare, auto, and life insurance domains. Our analysis reveals that ensemble methods combining CNNs with LSTMs achieve accuracies ranging from 89.6% to 98%, while GNN-based approaches demonstrate superior performance in detecting collusive fraud networks with accuracies exceeding 84%. The review identifies critical challenges including severe class imbalance with fraud rates of 0.03-3%, model interpretability requirements, and limited availability of labeled datasets. We examine emerging trends including explainable artificial intelligence (XAI) frameworks, attention mechanisms, generative adversarial networks (GANs) for synthetic data generation, and federated learning approaches for privacy-preserving fraud detection. This review contributes to understanding the current state-of-the-art in DL for insurance fraud detection while highlighting critical research gaps and future directions in model interpretability, cross-domain transfer learning, and real-time detection systems.

Fraud detection problems are usually formulated as a machine learning problem on a graph. Recently, Graph Neural Networks (GNNs) have shown solid performance on fraud detection. The successes of most previous methods heavily rely on rich node features and high-fidelity labels. However, labeled data is scarce in large-scale industrial problems, especially for fraud detection where new patterns emerge from time to time. Meanwhile, node features are also limited due to privacy and other constraints. In this paper, two improvements are proposed: 1) We design a graph transformation method capturing the structural information to facilitate GNNs on non-attributed fraud graphs. 2) We propose a novel graph pre-training strategy to leverage more unlabeled data via contrastive learning. Experiments on a large-scale industrial dataset demonstrate the effectiveness of the proposed framework for fraud detection.

Fund transfer fraud detection: Analyzing irregular transactions and customer relationships with self-attention and graph neural networks

This study demonstrates that the performance of Medicare fraud detection models can be improved by applying graph neural networks to graph-structured datasets. Tens of billions of dollars are lost to Medicare fraud yearly. Therefore, insurance companies constantly attempt to enhance fraud detection models to alleviate economic losses and reputational damage. While traditional rule-based or machine learning models have been extensively studied for Medicare fraud detection, graph learning has been used in very few studies. Thus, a Medicare fraud detection model that applies the GraphSAGE algorithm, a graph neural network, to graph-structured datasets generated from open-source data, including the information of Medicare providers, physicians, and beneficiaries, is presented in this paper. We developed a heterogeneous graph by setting the Medicare providers and beneficiaries as nodes. Consequently, the GraphSAGE model outperformed the baseline model in terms of precision, recall, F1score, and area under the receiver operating characteristics curve by 0.01, 0.35, 0.30, and 0.18, respectively. This result indicates that the graph relationship between the provider-beneficiary and provider-physician conveys important information that can be exploited for Medicare fraud detection.

Node classification is a substantial problem in graph-based fraud detection. Many existing works adopt Graph Neural Networks (GNNs) to enhance fraud detectors. While promising, currently most GNN-based fraud detectors fail to generalize to the low homophily setting. Besides, label utilization has been proved to be significant factor for node classification problem. But we find they are less effective in fraud detection tasks due to the low homophily in graphs. In this work, we propose GAGA, a novel Group AGgregation enhanced TrAnsformer, to tackle the above challenges. Specifically, the group aggregation provides a portable method to cope with the low homophily issue. Such an aggregation explicitly integrates the label information to generate distinguishable neighborhood information. Along with group aggregation, an attempt towards end-to-end trainable group encoding is proposed which augments the original feature space with the class labels. Meanwhile, we devise two additional learnable encodings to recognize the structural and relational context. Then, we combine the group aggregation and the learnable encodings into a Transformer encoder to capture the semantic information. Experimental results clearly show that GAGA outperforms other competitive graph-based fraud detectors by up to 24.39% on two trending public datasets and a real-world industrial dataset from Baidu. Even more, the group aggregation is demonstrated to outperform other label utilization methods (e.g., C&S, BoT/UniMP) in the low homophily setting.

The graph neural network (GNN) has recently become an emerging research topic for processing non-euclidean data structures since the data used in various popular application domains are usually modeled as a graph, such as social networks, recommendation systems, and computer vision. Previous GNN accelerators commonly utilize the hybrid architecture to resolve the issue of “hybrid computing pattern” in GNN training. Nevertheless, the hybrid architecture suffers from poor utilization of hardware resources mainly due to the dynamic workloads between different phases in GNN. To address these issues, existing GNN accelerators adopt a unified structure with numerous processing elements and high bandwidth memory. However, the large amount of data movement between the processor and memory could heavily downgrade the performance of such accelerators in real-world graphs. As a result, the processing-in-memory architecture, such as the ReRAM-based crossbar, becomes a promising solution to reduce the memory overhead of GNN training. In this work, we present the TCAM-GNN, a novel TCAM-based data processing strategy, to enable high-throughput and energy-efficient GNN training over ReRAM-based crossbar architecture. Several hardware co-designed data structures and placement methods are proposed to fully exploit the parallelism in GNN during training. In addition, we propose a dynamic fixed-point formatting approach to resolve the precision issue. An adaptive data reusing policy is also proposed to enhance the data locality of graph features by the bootstrapping batch sampling approach. Overall, TCAM-GNN could enhance computing performance by 4.25× and energy efficiency by 9.11× on average compared to the neural network accelerators.

Graph neural networks (GNNs) is an information - processing system that uses message passing among graph nodes. In recent years, GNN variants including graph attention network (GAT), graph convolutional network (GCN), and graph recurrent network (GRN) have shown revolutionary performance in computer vision applications using deep learning and artificial intelligence. These neural network model extensions, collect information in the form of graphs. GNN may be divided into three groups based on the challenges it solves: link prediction, node classification, graph classification. Machines can differentiate and recognise objects in image and video using standard CNNs. Extensive amount of research work needs to be done before robots can have same visual intuition as humans. GNN architectures, on the other hand, may be used to solve various image categorization and video challenges. The number of GNN applications in computer vision not limited, continues to expand. Human-object interaction, actin understanding, image categorization from a few shots and many more. In this paper use of GNN in image and video understanding, design aspects, architecture, applications and implementation challenges towards computer vision is described. GNN is a strong tool for analysing graph data and is still a relatively active area that needs further researches attention to solve many computer vision applications.

Sex classification is a major benchmark of previous work in learning on the structural connectome, a naturally occurring brain graph that has proven useful for studying cognitive function and impairment. While graph neural networks (GNNs), specifically graph convolutional networks (GCNs), have gained popularity lately for their effectiveness in learning on graph data, achieving strong performance in adult sex classification tasks, their application to pediatric populations remains unexplored. We seek to characterize the capacity for GNN models to learn connectomic patterns on pediatric data through an exploration of training techniques and architectural design choices. Two datasets comprising an adult BRIGHT dataset (N = 147 Hodgkin's lymphoma survivors and N = 162 age similar controls) and a pediatric Human Connectome Project in Development (HCP-D) dataset (N = 135 healthy subjects) were utilized. Two GNN models (GCN simple and GCN residual), a deep neural network (multi-layer perceptron), and two standard machine learning models (random forest and support vector machine) were trained. Architecture exploration experiments were conducted to evaluate the impact of network depth, pooling techniques, and skip connections on the ability of GNN models to capture connectomic patterns. Models were assessed across a range of metrics including accuracy, AUC score, and adversarial robustness. GNNs outperformed other models across both populations. Notably, adult GNN models achieved 85.1% accuracy in sex classification on unseen adult participants, consistent with prior studies. The extension of the adult models to the pediatric dataset and training on the smaller pediatric dataset were sub-optimal in their performance. Using adult data to augment pediatric models, the best GNN achieved comparable accuracy across unseen pediatric (83.0%) and adult (81.3%) participants. Adversarial sensitivity experiments showed that the simple GCN remained the most robust to perturbations, followed by the multi-layer perceptron and the residual GCN. These findings underscore the potential of GNNs in advancing our understanding of sex-specific neurological development and disorders and highlight the importance of data augmentation in overcoming challenges associated with small pediatric datasets. Further, they highlight relevant tradeoffs in the design landscape of connectomic GNNs. For example, while the simpler GNN model tested exhibits marginally worse accuracy and AUC scores in comparison to the more complex residual GNN, it demonstrates a higher degree of adversarial robustness.