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arXiv 2602.09593cs.LGcs.AI
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为何在基于深度生成模型的表格异常检测中,反直觉现象很少出现?

Why Does Counterintuitive Likelihood Behavior Rarely Emerge in Tabular Anomaly Detection?

Department of Industrial Engineering, University of Yonsei, Republic of Korea, Seoul(延世大学工业工程系);H. Milton Stewart School of Industrial and Systems Engineering (ISyE), Georgia Institute of Technology, USA, GA(佐治亚理工学院H.米尔顿·斯图尔特工业与系统工程学院)

Donghwan Kim, Junghun Phee, Hyunsoo Yoon

AI总结:

本文探讨了基于深度生成模型的表格异常检测中反直觉现象的罕见性,通过实验表明归一化流在表格数据中具有实用且可靠的异常检测能力。

摘要:

具有可计算和解析性似然的深度生成模型,例如归一化流,为通过似然评分进行异常检测提供了有效基础。我们证明,在图像领域中,深度生成模型经常将更高的似然分配给异常数据,而在表格设置中,这种反直觉行为出现得远不如图像领域频繁。我们首先引入了一个领域无关的公式,使能够一致地检测和评估反直觉现象,解决缺乏精确定义的问题。通过在47个表格数据集和10个CV/NLP嵌入数据集(ADBench)上进行广泛实验,并与13个基线模型进行基准测试,我们证明了在一般表格数据中,这种现象,如所定义的,通常是罕见的。我们进一步从理论和经验的角度研究了这一现象,重点研究数据维度和特征相关性差异的作用。我们的结果表明,仅使用似然的归一化流检测在表格领域中提供了一种实用且可靠的方法进行异常检测。

英文摘要:

Deep generative models with tractable likelihoods, exemplified by normalizing flows, offer an effective basis for anomaly detection through likelihood-based scoring. We demonstrate that, unlike in the image domain where deep generative models frequently assign higher likelihoods to anomalous data, such counterintuitive behavior occurs rarely in tabular settings. We first introduce a domain-agnostic formulation that enables consistent detection and evaluation of the counterintuitive phenomenon, addressing the lack of a precise definition in prior work. Through extensive experiments on 47 tabular datasets benchmarked against 13 baseline models and on 10 CV/NLP embedding datasets from ADBench, we show that the phenomenon is consistently rare in general tabular data and that normalizing flow likelihood achieves competitive anomaly detection performance. We further provide theoretical and empirical analyses attributing this disparity to differences in dimensionality and feature correlation between tabular and image data. Therefore, our results indicate that likelihood-based detection with normalizing flows is a practical approach for tabular anomaly detection.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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