Time-Varying Multi-Seasonal AR Models

Fuente: arXiv
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Main Authors: Fagerberg, Ganna, Villani, Mattias, Kohn, Robert
Format: Preprint
Published: 2024
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author Fagerberg, Ganna
Villani, Mattias
Kohn, Robert
author_facet Fagerberg, Ganna
Villani, Mattias
Kohn, Robert
contents We propose a seasonal AR model with time-varying parameter processes in both the regular and seasonal parameters. The model is parameterized to guarantee stability at every time point and can accommodate multiple seasonal periods. The time evolution is modeled by dynamic shrinkage processes to allow for long periods of essentially constant parameters, periods of rapid change, and abrupt jumps. A Gibbs sampler is developed with a particle Gibbs update step for the AR parameter trajectories. We show that the near-degeneracy of the model, caused by the dynamic shrinkage processes, makes it challenging to estimate the model by particle methods. To address this, a more robust, faster and accurate approximate sampler based on the extended Kalman filter is proposed. The model and the numerical effectiveness of the Gibbs sampler are investigated on simulated data. An application to more than a century of monthly US industrial production data shows interesting clear changes in seasonality over time, particularly during the Great Depression and the recent Covid-19 pandemic. Keywords: Bayesian inference; Extended Kalman filter; Particle MCMC; Seasonality.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18640
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Time-Varying Multi-Seasonal AR Models
Fagerberg, Ganna
Villani, Mattias
Kohn, Robert
Methodology
We propose a seasonal AR model with time-varying parameter processes in both the regular and seasonal parameters. The model is parameterized to guarantee stability at every time point and can accommodate multiple seasonal periods. The time evolution is modeled by dynamic shrinkage processes to allow for long periods of essentially constant parameters, periods of rapid change, and abrupt jumps. A Gibbs sampler is developed with a particle Gibbs update step for the AR parameter trajectories. We show that the near-degeneracy of the model, caused by the dynamic shrinkage processes, makes it challenging to estimate the model by particle methods. To address this, a more robust, faster and accurate approximate sampler based on the extended Kalman filter is proposed. The model and the numerical effectiveness of the Gibbs sampler are investigated on simulated data. An application to more than a century of monthly US industrial production data shows interesting clear changes in seasonality over time, particularly during the Great Depression and the recent Covid-19 pandemic. Keywords: Bayesian inference; Extended Kalman filter; Particle MCMC; Seasonality.
title Time-Varying Multi-Seasonal AR Models
topic Methodology
url https://arxiv.org/abs/2409.18640