Learning-Based Link Anomaly Detection in Continuous-Time Dynamic Graphs

Fuente: arXiv
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Main Authors: Poštuvan, Tim, Grohnfeldt, Claas, Russo, Michele, Lovisotto, Giulio
Format: Preprint
Published: 2024
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author Poštuvan, Tim
Grohnfeldt, Claas
Russo, Michele
Lovisotto, Giulio
author_facet Poštuvan, Tim
Grohnfeldt, Claas
Russo, Michele
Lovisotto, Giulio
contents Anomaly detection in continuous-time dynamic graphs is an emerging field yet under-explored in the context of learning algorithms. In this paper, we pioneer structured analyses of link-level anomalies and graph representation learning for identifying categorically anomalous graph links. First, we introduce a fine-grained taxonomy for edge-level anomalies leveraging structural, temporal, and contextual graph properties. Based on these properties, we introduce a method for generating and injecting typed anomalies into graphs. Next, we introduce a novel method to generate continuous-time dynamic graphs featuring consistencies across either or combinations of time, structure, and context. To enable temporal graph learning methods to detect specific types of anomalous links rather than the bare existence of a link, we extend the generic link prediction setting by: (1) conditioning link existence on contextual edge attributes; and (2) refining the training regime to accommodate diverse perturbations in the negative edge sampler. Comprehensive benchmarks on synthetic and real-world datasets -- featuring synthetic and labeled organic anomalies and employing six state-of-the-art link prediction methods -- validate our taxonomy and generation processes for anomalies and benign graphs, as well as our approach to adapting methods for anomaly detection. Our results reveal that different learning methods excel in capturing different aspects of graph normality and detecting different types of anomalies. We conclude with a comprehensive list of findings highlighting opportunities for future research.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18050
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Learning-Based Link Anomaly Detection in Continuous-Time Dynamic Graphs
Poštuvan, Tim
Grohnfeldt, Claas
Russo, Michele
Lovisotto, Giulio
Machine Learning
Artificial Intelligence
Cryptography and Security
Anomaly detection in continuous-time dynamic graphs is an emerging field yet under-explored in the context of learning algorithms. In this paper, we pioneer structured analyses of link-level anomalies and graph representation learning for identifying categorically anomalous graph links. First, we introduce a fine-grained taxonomy for edge-level anomalies leveraging structural, temporal, and contextual graph properties. Based on these properties, we introduce a method for generating and injecting typed anomalies into graphs. Next, we introduce a novel method to generate continuous-time dynamic graphs featuring consistencies across either or combinations of time, structure, and context. To enable temporal graph learning methods to detect specific types of anomalous links rather than the bare existence of a link, we extend the generic link prediction setting by: (1) conditioning link existence on contextual edge attributes; and (2) refining the training regime to accommodate diverse perturbations in the negative edge sampler. Comprehensive benchmarks on synthetic and real-world datasets -- featuring synthetic and labeled organic anomalies and employing six state-of-the-art link prediction methods -- validate our taxonomy and generation processes for anomalies and benign graphs, as well as our approach to adapting methods for anomaly detection. Our results reveal that different learning methods excel in capturing different aspects of graph normality and detecting different types of anomalies. We conclude with a comprehensive list of findings highlighting opportunities for future research.
title Learning-Based Link Anomaly Detection in Continuous-Time Dynamic Graphs
topic Machine Learning
Artificial Intelligence
Cryptography and Security
url https://arxiv.org/abs/2405.18050