Intelligent segmentation of anomalies in oceanographic data: comparative analysis of BiLSTM and TCN on time and time-frequency representations

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Abstract

This paper concerns the use of Deep Learning methods and Neural Networks for the task of segmentation and classification of hydrophysical time series in order to identify anomalies of a certain type caused by hardware failures. Two models based on Bidirectional Long-Short Term Memory networks and one based on a Temporal Convolutional Network were used. We made the performance comparisons and assessed the detection success. The results obtained demonstrate the effectiveness of the proposed approaches, and it was found that time-frequency analysis significantly improves the models’ ability to detect anomalies of different types.

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About the authors

R. A. Korotchenko

V. I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences

Email: kosheleva@poi.dvo.ru

Ph.D., Senior Researcher

Russian Federation, Vladivostok, 690041

A. V. Kosheleva

V. I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences

Author for correspondence.
Email: kosheleva@poi.dvo.ru

Researcher

Russian Federation, Vladivostok, 690041

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Supplementary files

Supplementary Files
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1. JATS XML
2. Fig. 1. A fragment of a synthetic time series saturated with “flash” anomalies

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3. Fig. 2. FSST spectrogram of a fragment of a time series containing anomalies

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4. Fig. 3. BiLSTM network diagram

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5. Rice. 4. TCN-FSST network diagram

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6. Fig. 5. Classification results. Error matrix: a — BiLSTM-TS; b — BiLSTM-FSST; c — TCN-FSST; d — TCN-FSST with weight balancing

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7. Fig. 6. Processing of test time series by TCN-FSST network with weight balancing

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