Evidential Spectrum-Aware Contrastive Learning for OOD Detection in Dynamic Graphs

Fuente: arXiv
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Autores principales: Sun, Nan, Lin, Xixun, Zhou, Zhiheng, Shang, Yanmin, Cheng, Zhenlin, Cao, Yanan
Formato: Preprint
Publicado: 2025
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author Sun, Nan
Lin, Xixun
Zhou, Zhiheng
Shang, Yanmin
Cheng, Zhenlin
Cao, Yanan
author_facet Sun, Nan
Lin, Xixun
Zhou, Zhiheng
Shang, Yanmin
Cheng, Zhenlin
Cao, Yanan
contents Recently, Out-of-distribution (OOD) detection in dynamic graphs, which aims to identify whether incoming data deviates from the distribution of the in-distribution (ID) training set, has garnered considerable attention in security-sensitive fields. Current OOD detection paradigms primarily focus on static graphs and confront two critical challenges: i) high bias and high variance caused by single-point estimation, which makes the predictions sensitive to randomness in the data; ii) score homogenization resulting from the lack of OOD training data, where the model only learns ID-specific patterns, resulting in overall low OOD scores and a narrow score gap between ID and OOD data. To tackle these issues, we first investigate OOD detection in dynamic graphs through the lens of Evidential Deep Learning (EDL). Specifically, we propose EviSEC, an innovative and effective OOD detector via Evidential Spectrum-awarE Contrastive Learning. We design an evidential neural network to redefine the output as the posterior Dirichlet distribution, explaining the randomness of inputs through the uncertainty of distribution, which is overlooked by single-point estimation. Moreover, spectrum-aware augmentation module generates OOD approximations to identify patterns with high OOD scores, thereby widening the score gap between ID and OOD data and mitigating score homogenization. Extensive experiments on real-world datasets demonstrate that EviSAC effectively detects OOD samples in dynamic graphs.
format Preprint
id arxiv_https___arxiv_org_abs_2506_07417
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evidential Spectrum-Aware Contrastive Learning for OOD Detection in Dynamic Graphs
Sun, Nan
Lin, Xixun
Zhou, Zhiheng
Shang, Yanmin
Cheng, Zhenlin
Cao, Yanan
Machine Learning
Artificial Intelligence
Recently, Out-of-distribution (OOD) detection in dynamic graphs, which aims to identify whether incoming data deviates from the distribution of the in-distribution (ID) training set, has garnered considerable attention in security-sensitive fields. Current OOD detection paradigms primarily focus on static graphs and confront two critical challenges: i) high bias and high variance caused by single-point estimation, which makes the predictions sensitive to randomness in the data; ii) score homogenization resulting from the lack of OOD training data, where the model only learns ID-specific patterns, resulting in overall low OOD scores and a narrow score gap between ID and OOD data. To tackle these issues, we first investigate OOD detection in dynamic graphs through the lens of Evidential Deep Learning (EDL). Specifically, we propose EviSEC, an innovative and effective OOD detector via Evidential Spectrum-awarE Contrastive Learning. We design an evidential neural network to redefine the output as the posterior Dirichlet distribution, explaining the randomness of inputs through the uncertainty of distribution, which is overlooked by single-point estimation. Moreover, spectrum-aware augmentation module generates OOD approximations to identify patterns with high OOD scores, thereby widening the score gap between ID and OOD data and mitigating score homogenization. Extensive experiments on real-world datasets demonstrate that EviSAC effectively detects OOD samples in dynamic graphs.
title Evidential Spectrum-Aware Contrastive Learning for OOD Detection in Dynamic Graphs
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2506.07417