Bi-level Heterogeneous Learning for Time Series Foundation Models: A Federated Learning Approach

Fuente: arXiv
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Main Authors: Chen, Shengchao, Long, Guodong, Liu, Dikai, Jiang, Jing
Format: Preprint
Published: 2026
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author Chen, Shengchao
Long, Guodong
Liu, Dikai
Jiang, Jing
author_facet Chen, Shengchao
Long, Guodong
Liu, Dikai
Jiang, Jing
contents Heterogeneity in time series data is more pronounced than in vision or language, as temporal dynamics vary substantially across domains and tasks. Existing efforts on training time series foundation models (TSFMs) from scratch are often trained with mixed-batch strategies that merge large-scale datasets, which can cause gradient conflicts and degrade representation quality. To address this, we propose a fine-grained learning method that distills invariant knowledge from heterogeneous series while reducing cross-domain interference. We characterize heterogeneity at two levels: inter-domain and intra-domain. To tackle this bi-level heterogeneity, we design a federated learning method that mitigates intra-domain conflicts by enforcing domain-invariant and semantically consistent representations through local regularization, and addresses inter-domain discrepancies by enhancing cross-domain collaboration via domain-aware aggregation. Experiments across diverse benchmarks show that TSFMs trained with our method consistently outperform both centralized and federated TSFM baselines in point and probabilistic forecasting, while also achieving competitive zero-shot performance at scale, offering a flexible pathway for training TSFMs from scratch in heterogeneous environments.
format Preprint
id arxiv_https___arxiv_org_abs_2604_06727
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Bi-level Heterogeneous Learning for Time Series Foundation Models: A Federated Learning Approach
Chen, Shengchao
Long, Guodong
Liu, Dikai
Jiang, Jing
Machine Learning
Heterogeneity in time series data is more pronounced than in vision or language, as temporal dynamics vary substantially across domains and tasks. Existing efforts on training time series foundation models (TSFMs) from scratch are often trained with mixed-batch strategies that merge large-scale datasets, which can cause gradient conflicts and degrade representation quality. To address this, we propose a fine-grained learning method that distills invariant knowledge from heterogeneous series while reducing cross-domain interference. We characterize heterogeneity at two levels: inter-domain and intra-domain. To tackle this bi-level heterogeneity, we design a federated learning method that mitigates intra-domain conflicts by enforcing domain-invariant and semantically consistent representations through local regularization, and addresses inter-domain discrepancies by enhancing cross-domain collaboration via domain-aware aggregation. Experiments across diverse benchmarks show that TSFMs trained with our method consistently outperform both centralized and federated TSFM baselines in point and probabilistic forecasting, while also achieving competitive zero-shot performance at scale, offering a flexible pathway for training TSFMs from scratch in heterogeneous environments.
title Bi-level Heterogeneous Learning for Time Series Foundation Models: A Federated Learning Approach
topic Machine Learning
url https://arxiv.org/abs/2604.06727