Property box center, Property box center uniformity, Property box radii – BUCHI NIRCal User Manual
Page 189: Property f-test backward, 54 property box center, 55 property box center uniformity, 56 property box radii, 57 property f-test backward
Chemometrics
NIRCal 5.5 Manual, Version A
189
3.18.54
Property Box Center
Description
The center position (expressed as score) of the smallest possible box in the
score space that contains each C-Set spectra of a property.
Use
Shows the distribution of the properties in the score space.
Method
Cluster (CLU) / SIMCA
Matrices ID
46
Tip
In higher PC dimensions the property box center falls together. These higher
PCs are useless for property separation, so remove them from the secondary
PC selection. See also the Property Box Radii matrix.
Details
Only C-Set spectra and C-Set property are used for calculations.
Related Topic
Property Box Radii
3.18.55
Property Box Center Uniformity
Description
Uniformity of the distribution of the Property Box Centers.
Use
Additional information for PCs selection.
Method
Cluster (CLU) / SIMCA
Matrices ID
51
Tip
Details
Estimates the place consumption of all properties per PC.
If several properties lay near each other in a PC, the PC becomes a low
uniformity value. A uniformity value of 1.0 is ideal.
Related Topic
Property Box Radi
i,
Property Box Center
,
Scores
3.18.56
Property Box Radii
Description
The distance from the Property Box Center to each wall of the smallest
property box.
Use
Shows the score distribution of the properties versus PCs. One of the best
matrix to select the secondary PCs for the cluster method.
Method
Cluster (CLU) / SIMCA
Matrices ID
47
Tip
Small values (normally bellow 0.1) indicate good reproducibility. To get good
separation of the properties select these PCs for the secondary PCs.
Details
Related Topic
Property Box Center
3.18.57
Property F-Test backward
Description
Significance of PCs starting at the minimum of the SEP function.
Use
For secondary principal component selection.
Method
PCR / PLS
Matrices ID
37
Tip
Details
Starting at the PCs they set the SEP value to the minimum, take PCs away
as long as no significant change for the worse of the SEP value occurs. This
process is called backward search operation.
Related Topic
Property F-Test forward