Ensemble robust SIMPLS with block-penalized smoothing for scalar-on-function regression


ALIN A.

Chemometrics and Intelligent Laboratory Systems, vol.269, 2026 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 269
  • Publication Date: 2026
  • Doi Number: 10.1016/j.chemolab.2025.105626
  • Journal Name: Chemometrics and Intelligent Laboratory Systems
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC
  • Keywords: Bootstrap, Functional data, Multicollinearity, Outliers, Penalization, PLSR, Robustness
  • Dokuz Eylül University Affiliated: Yes

Abstract

We propose a robust penalized smooth partial least squares approach that (i) smooths high-dimensional discretized functional predictors via blockwise B-spline bases, (ii) applies robust SIMPLS to obtain latent scores, (iii) fits a penalized regression in the latent space whose penalty is exactly a block-diagonal roughness penalty on the coefficient function(s), and (iv) aggregates models through bootstrap ensembles (classical/sufficient resampling; mean/median aggregation). The method supports multiple functional predictors through a block-diagonal construction and yields interpretable smooth coefficient functions. Our method demonstrates competitive or superior performance under collinearity and contamination.