MoDEx: Mixture of Depth-specific Experts for Multivariate Long-term Time Series Forecasting

Fuente: arXiv
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Main Authors: Yoon, Hyekyung, Lee, Minhyuk, Park, Imseung, Kang, Myungjoo
Format: Preprint
Published: 2026
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author Yoon, Hyekyung
Lee, Minhyuk
Park, Imseung
Kang, Myungjoo
author_facet Yoon, Hyekyung
Lee, Minhyuk
Park, Imseung
Kang, Myungjoo
contents Multivariate long-term time series forecasting (LTSF) supports critical applications such as traffic-flow management, solar-power scheduling, and electricity-transformer monitoring. The existing LTSF paradigms follow a three-stage pipeline of embedding, backbone refinement, and long-horizon prediction. However, the behaviors of individual backbone layers remain underexplored. We introduce layer sensitivity, a gradient-based metric inspired by GradCAM and effective receptive field theory, which quantifies both positive and negative contributions of each time point to a layer's latent features. Applying this metric to a three-layer MLP backbone reveals depth-specific specialization in modeling temporal dynamics in the input sequence. Motivated by these insights, we propose MoDEx, a lightweight Mixture of Depth-specific Experts, which replaces complex backbones with depth-specific MLP experts. MoDEx achieves state-of-the-art accuracy on seven real-world benchmarks, ranking first in 78 percent of cases, while using significantly fewer parameters and computational resources. It also integrates seamlessly into transformer variants, consistently boosting their performance and demonstrating robust generalizability as an efficient and high-performance LTSF framework.
format Preprint
id arxiv_https___arxiv_org_abs_2602_00624
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MoDEx: Mixture of Depth-specific Experts for Multivariate Long-term Time Series Forecasting
Yoon, Hyekyung
Lee, Minhyuk
Park, Imseung
Kang, Myungjoo
Machine Learning
Artificial Intelligence
Multivariate long-term time series forecasting (LTSF) supports critical applications such as traffic-flow management, solar-power scheduling, and electricity-transformer monitoring. The existing LTSF paradigms follow a three-stage pipeline of embedding, backbone refinement, and long-horizon prediction. However, the behaviors of individual backbone layers remain underexplored. We introduce layer sensitivity, a gradient-based metric inspired by GradCAM and effective receptive field theory, which quantifies both positive and negative contributions of each time point to a layer's latent features. Applying this metric to a three-layer MLP backbone reveals depth-specific specialization in modeling temporal dynamics in the input sequence. Motivated by these insights, we propose MoDEx, a lightweight Mixture of Depth-specific Experts, which replaces complex backbones with depth-specific MLP experts. MoDEx achieves state-of-the-art accuracy on seven real-world benchmarks, ranking first in 78 percent of cases, while using significantly fewer parameters and computational resources. It also integrates seamlessly into transformer variants, consistently boosting their performance and demonstrating robust generalizability as an efficient and high-performance LTSF framework.
title MoDEx: Mixture of Depth-specific Experts for Multivariate Long-term Time Series Forecasting
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.00624