Centrala begrepp
TSAP, a novel self-tuning self-supervised framework, can automatically select the appropriate anomaly type and tune the associated continuous hyperparameters to effectively detect diverse time series anomalies without any labeled data.
Sammanfattning
The paper introduces TSAP, a self-tuning self-supervised framework for time series anomaly detection (TSAD). The key contributions are:
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TSAP is the first approach that can automatically tune both the discrete (anomaly type) and continuous (anomaly hyperparameters) hyperparameters of the data augmentation process in a self-supervised setting, without any labeled data.
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The framework consists of two main components:
- A differentiable augmentation module that can generate pseudo-anomalies of various types (e.g., trend, extremum, amplitude shift) conditioned on the hyperparameters.
- A self-tuning module that iteratively optimizes the augmentation hyperparameters and the anomaly detector parameters, guided by an unsupervised validation loss that measures the alignment between the augmented data and the unlabeled test data.
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Experiments on both controlled and real-world TSAD tasks show that TSAP outperforms a diverse set of baselines, including state-of-the-art self-supervised methods. TSAP demonstrates the ability to accurately select the appropriate anomaly type and tune the associated continuous hyperparameters, leading to superior anomaly detection performance.
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Ablation studies highlight the importance of the proposed unsupervised validation loss and the self-tuning mechanism in driving the effectiveness of TSAP.
Statistik
The paper evaluates TSAP on six distinct TSAD tasks, four of which are in a controlled environment with manually injected anomalies, and two are in a natural environment with real-world anomalies.
The controlled tasks are based on the 2017 PhysioNet Challenge dataset, where different anomaly types (platform, trend, mean shift, etc.) are injected with varying hyperparameters (level, location, length).
The natural tasks are derived from the CMU Motion Capture (MoCap) dataset, where the walking signal is considered normal, and jumping and running signals are treated as anomalies.
Citat
"TSAP, a novel self-tuning self-supervised framework, can automatically select the appropriate anomaly type and tune the associated continuous hyperparameters to effectively detect diverse time series anomalies without any labeled data."
"Experiments on both controlled and real-world TSAD tasks show that TSAP outperforms a diverse set of baselines, including state-of-the-art self-supervised methods."