A classification tool for N-way arrays based on SIMCA methodology
A classification tool for N-way arrays based on SIMCA methodology
A classification tool for N-way arrays based on SIMCA methodology
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Overview of 2-<str<strong>on</strong>g>way</str<strong>on</strong>g> <strong>SIMCA</strong><br />
<strong>SIMCA</strong> evoluti<strong>on</strong><br />
robust <strong>SIMCA</strong> [1,2]<br />
- use robust PCA <str<strong>on</strong>g>for</str<strong>on</strong>g> class models<br />
- use a weighted sum of “reduced” orthog<strong>on</strong>al (OD, i.e. s<br />
(q)2<br />
p<br />
in previous slide) and<br />
Mahal<strong>on</strong>obis (MD, in scores space) distances<br />
- thus <str<strong>on</strong>g>classificati<strong>on</strong></str<strong>on</strong>g> rule will be to assign a new sample to the class <str<strong>on</strong>g>for</str<strong>on</strong>g> which R is<br />
minimal:<br />
R = © (OD/ODlim) + (1-©) (MD/MDlim)<br />
© in the range 0-1<br />
where MDlim is estimated by using as reference the chi-squared distributi<strong>on</strong> with dof<br />
equal to the number of retained comp<strong>on</strong>ents (A) and ODlim is estimated by assuming<br />
that a scaled versi<strong>on</strong> of chi-squared distributi<strong>on</strong> is appropriate (Wils<strong>on</strong>-Hilferty<br />
approximati<strong>on</strong>)<br />
1. K.V. Branden and M. Hubert, Chemolab 79 (2005) pp.10-21<br />
2. M. Daszykowski, K. Kaczmareck, I. Stanimirova, Y. Vander Heyden, B. Walczak<br />
Chemom. Intell. Lab. Syst. (2006)<br />
TRICAP 2009<br />
Dr. Marina CocchiMORE chemometrics,<br />
Department of Chemistry-University of Modena
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