Learnable Kernel Density Estimation for Graphs and Its Application to Graph-Level Anomaly Detection

Fuente: arXiv
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Autori principali: Wang, Xudong, Sun, Ziheng, Ding, Chris, Fan, Jicong
Natura: Preprint
Pubblicazione: 2025
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author Wang, Xudong
Sun, Ziheng
Ding, Chris
Fan, Jicong
author_facet Wang, Xudong
Sun, Ziheng
Ding, Chris
Fan, Jicong
contents This work proposes a framework LGKDE that learns kernel density estimation for graphs. The key challenge in graph density estimation lies in effectively capturing both structural patterns and semantic variations while maintaining theoretical guarantees. Combining graph kernels and kernel density estimation (KDE) is a standard approach to graph density estimation, but has unsatisfactory performance due to the handcrafted and fixed features of kernels. Our method LGKDE leverages graph neural networks to represent each graph as a discrete distribution and utilizes maximum mean discrepancy to learn the graph metric for multi-scale KDE, where all parameters are learned by maximizing the density of graphs relative to the density of their well-designed perturbed counterparts. The perturbations are conducted on both node features and graph spectra, which helps better characterize the boundary of normal density regions. Theoretically, we establish consistency and convergence guarantees for LGKDE, including bounds on the mean integrated squared error, robustness, and generalization. We validate LGKDE by demonstrating its effectiveness in recovering the underlying density of synthetic graph distributions and applying it to graph anomaly detection across diverse benchmark datasets. Extensive empirical evaluation shows that LGKDE demonstrates superior performance compared to state-of-the-art baselines on most benchmark datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2505_21285
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learnable Kernel Density Estimation for Graphs and Its Application to Graph-Level Anomaly Detection
Wang, Xudong
Sun, Ziheng
Ding, Chris
Fan, Jicong
Machine Learning
I.2; I.5.1; I.5.2
This work proposes a framework LGKDE that learns kernel density estimation for graphs. The key challenge in graph density estimation lies in effectively capturing both structural patterns and semantic variations while maintaining theoretical guarantees. Combining graph kernels and kernel density estimation (KDE) is a standard approach to graph density estimation, but has unsatisfactory performance due to the handcrafted and fixed features of kernels. Our method LGKDE leverages graph neural networks to represent each graph as a discrete distribution and utilizes maximum mean discrepancy to learn the graph metric for multi-scale KDE, where all parameters are learned by maximizing the density of graphs relative to the density of their well-designed perturbed counterparts. The perturbations are conducted on both node features and graph spectra, which helps better characterize the boundary of normal density regions. Theoretically, we establish consistency and convergence guarantees for LGKDE, including bounds on the mean integrated squared error, robustness, and generalization. We validate LGKDE by demonstrating its effectiveness in recovering the underlying density of synthetic graph distributions and applying it to graph anomaly detection across diverse benchmark datasets. Extensive empirical evaluation shows that LGKDE demonstrates superior performance compared to state-of-the-art baselines on most benchmark datasets.
title Learnable Kernel Density Estimation for Graphs and Its Application to Graph-Level Anomaly Detection
topic Machine Learning
I.2; I.5.1; I.5.2
url https://arxiv.org/abs/2505.21285