BUCHI NIRCal - Manual (Page 49)

Chemometrics
NIRCal 5.5 Manual, Version A 49
Distance
The distance to the next calibration spectra should be smaller, than the tolerance ring radius of the
neighboring calibration spectrum. In this case the distance criterion is OK, the spectrum is in a
cluster.
Property Residuum zero means, all spectra are in the correct cluster.
Here only a value of 0 is acceptable.
Property Residuum +1 means, that a spectrum is outside the cluster: it is not identified.
Property Residuum
–1 means, that a spectrum is in a wrong cluster: it is false identified.
Residual
The [(maximum residual of a C-Set) * 2] is the max. allowed residual for the calibration and later for
the application.
The default residual Blow up factor is 2, it may be changed by the user (it is not suggested to use
smaller values as 1).
Spectra Residual too big should be for all spectra zero.
These three criteria are showed in the Overview plot in the 2nd column.
3.1.3 SIMCA
SIMCA is a calibration method used for identification of substances. Using SIMCA a Principal
Component Analysis (PCA) is made for each substance/property in the project, but each calibration
is made for only one substance.
Cluster calibrations can be transformed to several SIMCA calibrations. See
Transform Cluster to
SIMCA .
This tool creates for all C-Set properties one SIMCA calibration, the name of the calibration is "SIMCA
+ calibrated property name".
All SIMCA calibrations take over the following default parameters:

the spectra C-Set and V-Set selection of the last active cluster calibration;

the wavelength selection from the selection of the last active cluster calibration;

pretreatments of the last active cluster calibration;

the "Mean centering after Pretreatments" is still switched on; represent the mean value
spectrum;