This paper addresses the challenges of complex dependencies and diverse anomaly patterns in cloud service environments by proposing a dependency modeling and anomaly detection method that integrates contrastive learning. The method abstracts service interactions into a dependency graph, extracts temporal and structural features through embedding functions, and employs a graph convolution mechanism to aggregate neighborhood information for context-aware service representations. A contrastive learning framework is then introduced, constructing positive and negative sample pairs to enhance the separability of normal and abnormal patterns in the representation space. Furthermore, a temporal consistency constraint is designed to maintain representation stability across time steps and reduce the impact of short-term fluctuations and noise. The overall optimization combines contrastive loss and temporal consistency loss to ensure stable and reliable detection across multi-dimensional features. Experiments on public datasets systematically evaluate the method from hyperparameter, environmental, and data sensitivity perspectives. Results show that the proposed approach significantly outperforms existing methods on key metrics such as Precision, Recall, F1-Score, and AUC, while maintaining robustness under conditions of sparse labeling, monitoring noise, and traffic fluctuations. This study verifies the effectiveness of integrating dependency modeling with contrastive learning, provides a complete technical solution for cloud service anomaly detection, and demonstrates strong adaptability and stability in complex environments.
La Trobe University（乐卓博大学）；Monash University（蒙纳士大学）
Anomaly detection from graph data has drawn much attention due to its practical significance in many critical applications including cybersecurity, finance, and social networks. Existing data mining and machine learning methods are either shallow methods that could not effectively capture the complex interdependency of graph data or graph autoencoder methods that could not fully exploit the contextual information as supervision signals for effective anomaly detection. To overcome these challenges, in this paper, we propose a novel method, Self-Supervised Learning for Graph Anomaly Detection (S…
Monash University（莫纳什大学）；Alibaba Group（阿里巴巴集团）；Nanjing University of Science and Technology（南京理工大学）；The Hong Kong Polytechnic University（香港理工大学）；Chinese Academy of Sciences（中国科学院）；University of Minnesota（明尼苏达大学）
Anomaly detection on attributed networks attracts considerable research interests due to wide applications of attributed networks in modeling a wide range of complex systems. Recently, the deep learning-based anomaly detection methods have shown promising results over shallow approaches, especially on networks with high-dimensional attributes and complex structures. However, existing approaches, which employ graph autoencoder as their backbone, do not fully exploit the rich information of the network, resulting in suboptimal performance. Furthermore, these methods do not directly target anomal…
Deep anomaly detection methods learn representations that separate between normal and anomalous images. Although self-supervised representation learning is commonly used, small dataset sizes limit its effectiveness. It was previously shown that utilizing external, generic datasets (e.g. ImageNet classification) can significantly improve anomaly detection performance. One approach is outlier exposure, which fails when the external datasets do not resemble the anomalies. We take the approach of transferring representations pre-trained on external datasets for anomaly detection. Anomaly detection…
Tsinghua University（清华大学）；Renmin University of China（中国人民大学）；Mininglamp Technology（明略科技）；Bosch Center for Artificial Intelligence（博世人工智能中心）；University of Oslo（奥斯陆大学）
Graph-based anomaly detection has been widely used for detecting malicious activities in real-world applications. Existing attempts to address this problem have thus far focused on structural feature engineering or learning in the binary classification regime. In this work, we propose to leverage graph contrastive coding and present the supervised GraphCAD model for contrasting abnormal nodes with normal ones in terms of their distances to the global context (e.g., the average of all nodes). To handle scenarios with scarce labels, we further enable GraphCAD as a self-supervised framework by de…
Behavioral Anomaly Detection in Distributed Systems via Federated Contrastive Learning
Northeastern University（东北大学）；Illinois Institute of Technology（伊利诺伊理工学院）；Rochester Institute of Technology（罗切斯特理工学院）；University of California, San Diego（加利福尼亚大学圣地亚哥分校）；University of Southern California（南加利福尼亚大学）；University of Michigan（密歇根大学）
Graph anomaly detection (GAD) is a vital task in graph-based machine learning and has been widely applied in many real-world applications. The primary goal of GAD is to capture anomalous nodes from graph datasets, which evidently deviate from the majority of nodes. Recent methods have paid attention to various scales of contrastive strategies for GAD, i.e., node-subgraph and node-node contrasts. However, they neglect the subgraph-subgraph comparison information which the normal and abnormal subgraph pairs behave differently in terms of embeddings and structures in GAD, resulting in sub-optimal…
Detecting anomalies is one fundamental aspect of a safety-critical software system, however, it remains a long-standing problem. Numerous branches of works have been proposed to alleviate the complication and have demonstrated their efficiencies. In particular, self-supervised learning based methods are spurring interest due to their capability of learning diverse representations without additional labels. Among self-supervised learning tactics, contrastive learning is one specific framework validating their superiority in various fields, including anomaly detection. However, the primary objec…
EAGLE: Contrastive Learning for Efficient Graph Anomaly Detection
Institute of Innovation, Science and Sustainability, Federation University Australia（创新、科学与可持续性研究所，联邦大学澳大利亚）；School of Software, Dalian University of Technology（软件学院，大连理工大学）；Computing Center, Anshan Normal University（计算机中心，鞍山师范学院）
Text-Attributed Graph Anomaly Detection via Multi-Scale Cross- and Uni-Modal Contrastive Learning
School of Computer Science and Technology, Xi'an Jiaotong University（西安交通大学计算机科学与技术学院）；Shaanxi Provincial Key Laboratory of Big Data Knowledge Engineering, Xi’an Jiaotong University（陕西省大数据知识工程重点实验室）；School of Distance Education, Xi’an Jiaotong University（西安交通大学继续教育学院）；University of Virginia（弗吉尼亚大学）
DACAD: Domain Adaptation Contrastive Learning for Anomaly Detection in Multivariate Time Series
Department of Data Science and AI, Monash University（数据科学与人工智能系，墨尔本大学）；Department of Computer Science, University of Oxford（计算机科学系，牛津大学）；IBM T. J. Watson Research Center（IBM T. J. Watson研究中心）；Squirrel Ai Learning（Squirrel Ai Learning公司）；School of ICT, Griffith University（信息科技学院，格里菲斯大学）
Distracted drivers are more likely to fail to anticipate hazards, which result in car accidents. Therefore, detecting anomalies in drivers' actions (i.e., any action deviating from normal driving) contains the utmost importance to reduce driver-related accidents. However, there are unbounded many anomalous actions that a driver can do while driving, which leads to an 'open set recognition' problem. Accordingly, instead of recognizing a set of anomalous actions that are commonly defined by previous dataset providers, in this work, we propose a contrastive learning approach to learn a metric to …
ContraLog: Log File Anomaly Detection with Contrastive Learning and Masked Language Modeling
Munich Center for Machine Learning（慕尼黑机器学习中心）；LMU München（慕尼黑大学）；German Research Center for Environmental Health, Helmholtz Zentrum München（德国环境健康研究中心，亥姆霍兹慕尼黑中心）
SCALA: Sparsification-based Contrastive Learning for Anomaly Detection on Attributed Networks
College of Computer Science and Technology, Harbin Engineering University（哈尔滨工程大学计算机科学与技术学院）；School of Computer Science and Engineering, University of New South Wales（新南威尔士大学计算机科学与工程学院）
DConAD: A Differencing-based Contrastive Representation Learning Framework for Time Series Anomaly Detection
University of Chinese Academy of Science（中国科学院大学）；Tsinghua University（清华大学）；Shanghai University of International Business and Economics（上海国际商务经济学院）；Northeast Normal University（东北师范大学）；Fuzhou University（福州市大学）；Hubei University（湖北大学）；Hainan University（海南大学）；Northeastern University（东北大学）
Traditional supervised learning methods are hitting a bottleneck because of their dependency on expensive manually labeled data and their weaknesses such as limited generalization ability and vulnerability to adversarial attacks. A promising alternative, self-supervised learning, as a type of unsupervised learning, has gained popularity because of its potential to learn effective data representations without manual labeling. Among self-supervised learning algorithms, contrastive learning has achieved state-of-the-art performance in several fields of research. This literature review aims to pro…
There have been several recent efforts towards developing representations for multivariate time-series in an unsupervised learning framework. Such representations can prove beneficial in tasks such as activity recognition, health monitoring, and anomaly detection. In this paper, we consider a setting where we observe time-series at each node in a dynamic graph. We propose a framework called GraphTNC for unsupervised learning of joint representations of the graph and the time-series. Our approach employs a contrastive learning strategy. Based on an assumption that the time-series and graph evol…
Hamburg University of Technology（汉堡工业大学）；University Medical Center Hamburg-Eppendorf（汉堡-埃彭多夫大学医学中心）；University Heart and Vascular Center（大学心血管中心）
Using deep learning techniques, anomalies in the paranasal sinus system can be detected automatically in MRI images and can be further analyzed and classified based on their volume, shape and other parameters like local contrast. However due to limited training data, traditional supervised learning methods often fail to generalize. Existing deep learning methods in paranasal anomaly classification have been used to diagnose at most one anomaly. In our work, we consider three anomalies. Specifically, we employ a 3D CNN to separate maxillary sinus volumes without anomalies from maxillary sinus v…
DrugCLIP: Contrastive Protein-Molecule Representation Learning for Virtual Screening
Institute for AI Industry Research（人工智能产业研究院）；Tsinghua University（清华大学）；Peking University（北京大学）；Institute of Automation（自动化研究所）；Chinese Academy of Science（中国科学院）
A Generative Graph Contrastive Learning Model with Global Signal
College of Han Hong, Southwest University, Chongqing, China（Honghan College, Southwest University）；College of Computer and Information Science, Southwest University, Chongqing, China（Computer and Information Science College, Southwest University）
Virginia Tech（弗吉尼亚理工大学）；Stevens Institute of Technology（史蒂文斯理工学院）；DeepSig Inc（DeepSig公司）
Anomaly detection is a ubiquitous and challenging task relevant across many disciplines. With the vital role communication networks play in our daily lives, the security of these networks is imperative for smooth functioning of society. To this end, we propose a novel self-supervised deep learning framework CAAD for anomaly detection in wireless communication systems. Specifically, CAAD employs contrastive learning in an adversarial setup to learn effective representations of normal and anomalous behavior in wireless networks. We conduct rigorous performance comparisons of CAAD with several st…
Carnegie Mellon University（卡内基梅隆大学）；University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
Contrastive learning has been applied successfully to learn vector representations of text. Previous research demonstrated that learning high-quality representations benefits from batch-wise contrastive loss with a large number of negatives. In practice, the technique of in-batch negative is used, where for each example in a batch, other batch examples' positives will be taken as its negatives, avoiding encoding extra negatives. This, however, still conditions each example's loss on all batch examples and requires fitting the entire large batch into GPU memory. This paper introduces a gradient…
A theoretical framework for self-supervised contrastive learning for continuous dependent data
Applied AI Center Skoltech Moscow, Russia；Applied AI Center Skoltech MIPT Moscow, Russia；Applied AI Center Skoltech Risk Management Sber Moscow, Russia
Unsupervised learning has recently made exceptional progress because of the development of more effective contrastive learning methods. However, CNNs are prone to depend on low-level features that humans deem non-semantic. This dependency has been conjectured to induce a lack of robustness to image perturbations or domain shift. In this paper, we show that by generating carefully designed negative samples, contrastive learning can learn more robust representations with less dependence on such features. Contrastive learning utilizes positive pairs that preserve semantic information while pertur…
Towards Understanding the Mechanism of Contrastive Learning via Similarity Structure: A Theoretical Analysis
Tokyo Institute of Technology（东京工业大学）；Fujitsu（富士通）；RIKEN AIP（理化学研究所人工智能研究中心）；Institut de Mathématiques de Toulouse（图卢兹数学研究所）；SNCF（法国国家铁路公司）；Université de Toulouse（图卢兹大学）；CNRS（法国国家科学研究中心）
Detecting Multilevel Manipulation from Limit Order Book via Cascaded Contrastive Representation Learning
Guangdong Provincial Key Laboratory of Brain-inspired Intelligent Computation, Department of Computer Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China（广东省脑启发智能计算重点实验室，计算机科学与工程系，南方科技大学，深圳518055，中国）；Department of Statistics and Data Science, Southern University of Science and Technology, Shenzhen 518055, China（统计与数据科学系，南方科技大学，深圳518055，中国）
Temporal knowledge graph, serving as an effective way to store and model dynamic relations, shows promising prospects in event forecasting. However, most temporal knowledge graph reasoning methods are highly dependent on the recurrence or periodicity of events, which brings challenges to inferring future events related to entities that lack historical interaction. In fact, the current moment is often the combined effect of a small part of historical information and those unobserved underlying factors. To this end, we propose a new event forecasting model called Contrastive Event Network (CENET…
Prior-Fitted and Frozen Scorers for Multimodal Contrastive Learning
Berlin Institute of Health（柏林卫生研究所）；Charité - Universitätsmedizin Berlin（柏林夏里特医学院）；Freie Universität Berlin（柏林自由大学）；Intelligent Medicine Institute（智能医学研究所）；Fudan University（复旦大学）
Contrastive Representation Modeling for Anomaly Detection
Technology Innovation Institute, Abu Dhabi, UAE（阿布扎比技术创新研究所）；Computer Science Department, Khalifa University of Science and Technology, Abu Dhabi, UAE（科技学院计算机科学系）
Datasets for biosignals, such as electroencephalogram (EEG) and electrocardiogram (ECG), often have noisy labels and have limited number of subjects (<100). To handle these challenges, we propose a self-supervised approach based on contrastive learning to model biosignals with a reduced reliance on labeled data and with fewer subjects. In this regime of limited labels and subjects, intersubject variability negatively impacts model performance. Thus, we introduce subject-aware learning through (1) a subject-specific contrastive loss, and (2) an adversarial training to promote subject-invariance…
Learning effective visual representations without human supervision is a long-standing problem in computer vision. Recent advances in self-supervised learning algorithms have utilized contrastive learning, with methods such as SimCLR, which applies a composition of augmentations to an image, and minimizes a contrastive loss between the two augmented images. In this paper, we present CLAWS, an annotation-efficient learning framework, addressing the problem of manually labeling large-scale agricultural datasets along with potential applications such as anomaly detection and plant growth analytic…
Reliable detection of anomalies is crucial when deploying machine learning models in practice, but remains challenging due to the lack of labeled data. To tackle this challenge, contrastive learning approaches are becoming increasingly popular, given the impressive results they have achieved in self-supervised representation learning settings. However, while most existing contrastive anomaly detection and segmentation approaches have been applied to images, none of them can use the contrastive losses directly for both anomaly detection and segmentation. In this paper, we close this gap by maki…
Rethinking Contrastive Learning in Graph Anomaly Detection: A Clean-View Perspective
College of Intelligence and Computing, Tianjin University（天津大学智能计算学院）；Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ)（广东人工智能与数字经济实验室（深圳））；Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences（深圳先进技术研究院，中国科学院）
