计算机科学 ›› 2026, Vol. 53 ›› Issue (7): 298-307.doi: 10.11896/jsjkx.260200102

• 数据库 & 大数据 & 数据科学 • 上一篇    下一篇

面向医保无监督异常检测的自回归序列重构方法

纪文迪, 王永全   

  1. 华东政法大学刑事法学院 上海 201620
    华东政法大学智能科学与信息法学系 上海 201620
  • 收稿日期:2026-01-06 修回日期:2026-04-14 出版日期:2026-07-15 发布日期:2026-07-10
  • 通讯作者: 王永全(wangyongquan@ecupl.edu.cn)
  • 基金资助:
    国家重点研发计划(2023YFC3306100,2023YFC3306103,2023YFC3306105)

Autoregressive Sequence Reconstruction for Unsupervised Anomaly Detection in Medical Insurance

JI Wendi, WANG Yongquan   

  1. School of Law and Criminal Justice,East China University of Political Science and Law,Shanghai 201620,China
    Department of Intelligent Science and Information Law,East China University of Political Science and Law,Shanghai 201620,China
  • Received:2026-01-06 Revised:2026-04-14 Published:2026-07-15 Online:2026-07-10
  • About author:JI Wendi,born in 1988,Ph.D,lecturer,is a member of CCF(No.D8438M).Her main research interests include na-tural language processing,information retrieval and computational law.
    WANG Yongquan,born in 1964,Ph.D,professor,Ph.D supervisor.His main research interests include big data and artificial intelligence,cyberspace security and cybercrime,digital forensics.
  • Supported by:
    National Key Research and Development Program of China(2023YFC3306100, 2023YFC3306103,2023YFC3306105).

摘要: 异常检测是医保基金监管中的关键技术。现有主流方法多依赖复杂的特征工程与业务专家经验来刻画可疑行为,检测规则的构建与维护成本高,且难以适应不断演化的欺诈模式。同时,医保异常标签稀缺、滞后且噪声较高,进一步制约了监督方法的可靠落地。为此,提出面向医保的无监督异常检测框架SeqRecon-AD,以医保账户的结算项目为基本单位,将账户历史按时间组织为项目序列,通过刻画序列在正常转移规律下的偏离程度来度量账户风险。模型采用自回归Transformer学习项目间的转移模式,以下一项目预测为训练目标,建模正常医保行为的序列规律。随后,计算位置级负对数似然损失,通过Top-k损失聚合得到账户级异常分数,从而突出少量关键异常片段的贡献,避免均值聚合对异常信号的稀释。在真实城市级数据集上进行了实验,结果表明,SeqRecon-AD优于经典无监督基线、代表性序列模型以及重构式自编码器方法,在不依赖训练异常标签的条件下提供了有效、可部署的无监督检测方案,相比最优无监督基线方法,其AUC提升了29.21%。

关键词: 医保异常检测, 无监督学习, 序列重构, 自回归Transformer, Top-k损失聚合

Abstract: Anomaly detection is a key technique for medical insurance fund supervision.Most existing approaches rely on complex feature engineering and domain expertise to characterize suspicious behaviors,making rules costly to build and maintain and difficult to adapt to evolving fraud patterns.Meanwhile,labels are also scarce,delayed,and noisy,further limiting the reliable deployment of supervised methods.To this end,this paper presents SeqRecon-AD(Sequence Reconstruction for Anomaly Detection),an unsupervised anomaly detection framework in medical insurance that models each account as a time-ordered sequence of reimbursed items and measures account risk by its deviation from normal transition patterns.Specifically,an autoregressive Transformer is trained with a next-item reconstruction objective to capture regular item transitions.Token-level negative log-likelihood losses are then aggregated into an account-level anomaly score via Top-k loss aggregation,which emphasizes sparse abnormal segments rather than average behavior.Experimental results on a real-world city-scale dataset show that SeqRecon-AD outperforms classical unsupervised baselines,representative sequence models as well as reconstruction-based autoencoders.SeqRecon-AD provides an effective and deployable unsupervised solution for medical insurance anomaly detection without relying on anomaly labels for training,improving AUC by 29.21% over the best unsupervised baseline.

Key words: Medical insurance anomaly detection, Unsupervised learning, Sequence reconstruction, Autoregressive Transformer, Top-k loss aggregation

中图分类号: 

  • TP391
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