Evo-TFS: Evolutionary Time-Frequency Domain-Based Synthetic Minority Oversampling Approach to Imbalanced Time Series Classification

Fuente: arXiv
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Auteurs principaux: Pei, Wenbin, Dai, Ruohao, Xue, Bing, Zhang, Mengjie, Zhang, Qiang, Cheung, Yiu-Ming
Format: Preprint
Publié: 2026
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author Pei, Wenbin
Dai, Ruohao
Xue, Bing
Zhang, Mengjie
Zhang, Qiang
Cheung, Yiu-Ming
author_facet Pei, Wenbin
Dai, Ruohao
Xue, Bing
Zhang, Mengjie
Zhang, Qiang
Cheung, Yiu-Ming
contents Time series classification is a fundamental machine learning task with broad real-world applications. Although many deep learning methods have proven effective in learning time-series data for classification, they were originally developed under the assumption of balanced data distributions. Once data distribution is uneven, these methods tend to ignore the minority class that is typically of higher practical significance. Oversampling methods have been designed to address this by generating minority-class samples, but their reliance on linear interpolation often hampers the preservation of temporal dynamics and the generation of diverse samples. Therefore, in this paper, we propose Evo-TFS, a novel evolutionary oversampling method that integrates both time- and frequency-domain characteristics. In Evo-TFS, strongly typed genetic programming is employed to evolve diverse, high-quality time series, guided by a fitness function that incorporates both time-domain and frequency-domain characteristics. Experiments conducted on imbalanced time series datasets demonstrate that Evo-TFS outperforms existing oversampling methods, significantly enhancing the performance of time-domain and frequency-domain classifiers.
format Preprint
id arxiv_https___arxiv_org_abs_2601_01150
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Evo-TFS: Evolutionary Time-Frequency Domain-Based Synthetic Minority Oversampling Approach to Imbalanced Time Series Classification
Pei, Wenbin
Dai, Ruohao
Xue, Bing
Zhang, Mengjie
Zhang, Qiang
Cheung, Yiu-Ming
Machine Learning
Neural and Evolutionary Computing
Time series classification is a fundamental machine learning task with broad real-world applications. Although many deep learning methods have proven effective in learning time-series data for classification, they were originally developed under the assumption of balanced data distributions. Once data distribution is uneven, these methods tend to ignore the minority class that is typically of higher practical significance. Oversampling methods have been designed to address this by generating minority-class samples, but their reliance on linear interpolation often hampers the preservation of temporal dynamics and the generation of diverse samples. Therefore, in this paper, we propose Evo-TFS, a novel evolutionary oversampling method that integrates both time- and frequency-domain characteristics. In Evo-TFS, strongly typed genetic programming is employed to evolve diverse, high-quality time series, guided by a fitness function that incorporates both time-domain and frequency-domain characteristics. Experiments conducted on imbalanced time series datasets demonstrate that Evo-TFS outperforms existing oversampling methods, significantly enhancing the performance of time-domain and frequency-domain classifiers.
title Evo-TFS: Evolutionary Time-Frequency Domain-Based Synthetic Minority Oversampling Approach to Imbalanced Time Series Classification
topic Machine Learning
Neural and Evolutionary Computing
url https://arxiv.org/abs/2601.01150