Railway Track Quality Inspection via GLasso with Zero-Crossing Segmentation
摘要
This study presents an approach for monitoring the transient variations in the multivariate coefficient of variation (MCV) using one-sided downward and upward control charts. Zero-crossing segmentation was employed to form subgroups, enabling efficient detection of process shifts. The methodology was applied to track geometry data collected from multiple railway sections across Hungary. Control charts were developed using both Maximum Likelihood Estimation (MLE) and Graphical Lasso (GLasso) techniques for estimating the precision matrix. Comparative analysis revealed that GLasso-based MCV charts with zero-crossing segmentation outperformed their MLE-based counterparts in detecting process changes.