### Abstract

Original language | English |
---|---|

Title of host publication | Proceedings of CAC 2012 |

Publication status | Published - 2012 |

MoE publication type | D3 Professional conference proceedings |

Event | XXIIth Chemometrics in Analytical Chemistry, CAC 2012 - Budapest, Hungary Duration: 25 Jun 2012 → 29 Jun 2012 |

### Conference

Conference | XXIIth Chemometrics in Analytical Chemistry, CAC 2012 |
---|---|

Abbreviated title | CAC 2012 |

Country | Hungary |

City | Budapest |

Period | 25/06/12 → 29/06/12 |

### Fingerprint

### Keywords

- Generalized ridge regression
- rational function ridge regression
- chemometrics
- PAT
- chemical imaging

### Cite this

*Proceedings of CAC 2012*

}

*Proceedings of CAC 2012.*XXIIth Chemometrics in Analytical Chemistry, CAC 2012, Budapest, Hungary, 25/06/12.

**Sparse rational function methods for developing parsimonious multivariate calibrations.** / Teppola, Pekka; Taavitsainen, Veli-Matti.

Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Professional

TY - GEN

T1 - Sparse rational function methods for developing parsimonious multivariate calibrations

AU - Teppola, Pekka

AU - Taavitsainen, Veli-Matti

PY - 2012

Y1 - 2012

N2 - The aim is to demonstrate the flexibility and robustness of two new additions to the rational function methods, namely, rational function least angle regression (LARS), rational function least absolute shrinkage and selection operator (LASSO) and elastic net (ENET) methods. Previous work [1, 2] has been based on the methods that use a L2 regularization to cope with collinearity and measurement noise. In this work, we introduce parsimonious methods for rational function modeling that use rather L1 regularization or the combination of L1 and L2 regularization. These methods provide interesting opportunities for model development and robustification. The key point is to specifically illustrate the flexibility of rational function ENET because it bridges the gap between L1 and L2 methods. The former suffers from spectral noise, which is well known in the context of normal LASSO approaches. The latter has been troublesome in numerous occasions as it involves the use of a broad spectral range that is often prone to suffer from unknown spectral interferences in future samples. These points will also be exemplified using two data sets generated by a multipoint NIR instrument with two 5-channel measurement probes and by a chemical imaging NIR spectrometer. We also briefly demonstrate how to interpret and visualize rational function models efficiently. In summary, this work addresses new and interesting directions in developing calibration models in the field of spectroscopy and multipoint measurements.

AB - The aim is to demonstrate the flexibility and robustness of two new additions to the rational function methods, namely, rational function least angle regression (LARS), rational function least absolute shrinkage and selection operator (LASSO) and elastic net (ENET) methods. Previous work [1, 2] has been based on the methods that use a L2 regularization to cope with collinearity and measurement noise. In this work, we introduce parsimonious methods for rational function modeling that use rather L1 regularization or the combination of L1 and L2 regularization. These methods provide interesting opportunities for model development and robustification. The key point is to specifically illustrate the flexibility of rational function ENET because it bridges the gap between L1 and L2 methods. The former suffers from spectral noise, which is well known in the context of normal LASSO approaches. The latter has been troublesome in numerous occasions as it involves the use of a broad spectral range that is often prone to suffer from unknown spectral interferences in future samples. These points will also be exemplified using two data sets generated by a multipoint NIR instrument with two 5-channel measurement probes and by a chemical imaging NIR spectrometer. We also briefly demonstrate how to interpret and visualize rational function models efficiently. In summary, this work addresses new and interesting directions in developing calibration models in the field of spectroscopy and multipoint measurements.

KW - Generalized ridge regression

KW - rational function ridge regression

KW - chemometrics

KW - PAT

KW - chemical imaging

M3 - Conference article in proceedings

BT - Proceedings of CAC 2012

ER -