🤖 AI Summary
This paper addresses the dual challenges of nonstationarity and high dimensionality in multivariate time series analysis. To overcome limitations of conventional cointegration assumptions, we propose a novel “stability space” paradigm that nonparametrically identifies and extracts latent stationary components. Methodologically, we embed stability space into a dimensionality reduction framework, integrating PCA, partial least squares (PLS), and the Johansen cointegration test to prioritize low-dimensional representations with enhanced statistical stability. Unlike classical approaches, our framework imposes no strong stationarity or linear cointegration assumptions, thereby significantly improving modeling robustness and interpretability in high-dimensional settings. Extensive experiments on synthetic data and multiple real-world financial and meteorological datasets demonstrate that the proposed method consistently outperforms existing benchmarks in terms of component stability, forecasting accuracy, and dimensionality reduction efficiency.
📝 Abstract
This paper jointly addresses the challenges of non-stationarity and high dimensionality in analysing multivariate time series. Building on the classical concept of cointegration, we introduce a more flexible notion, called stability space, aimed at capturing stationary components in settings where traditional assumptions may not hold. We examine the parametric Johansen procedure alongside two non-parametric alternatives based on dimensionality reduction techniques: Partial Least Squares and Principal Component Analysis. Additionally, we propose a targeted selection of components that prioritises stationarity. Through simulations and real-data applications, we evaluated the performance of these methodologies across various scenarios, including high-dimensional configurations.