Problems of Forensic Sciences 2016 Vol. 107 (CVII) 537-556
SOME REMARKS AND SUGGESTIONS CONCERNING EXAMINATION OF SIMILARITY BETWEEN OBJECTS
Andrzej PARCZEWSKI1,Paulina CHĘSY1,2
1Faculty of Chemistry, Jagiellonian University in Krakow, Kraków, Poland a professor emeritus
2Institute of General and Ecological Chemistry, Faculty of Chemistry, Lodz University of Technology, Łódź, Poland
Streszczenie
A scheme of examination of similarity between objects (e.g. environmental samples, pieces of evidence in forensic investigation) is suggested which comprises simultaneously two types of similarity: between values of the corresponding variables selected for the description of the objects tested, and between shapes of data profiles of the objects. Both types of similarity are presented using: visualization of original data profiles and profiles after the original data were autoscaled along rows of the raw data matrix, visualization of similarity between shape of data profile of a selected object and the shapes of data profiles of the remaining objects, visualization of both types of similarity using dendrograms as well as simultaneous visualization of both types of similarity between objects using original symbolic matrices. Also a procedure is proposed which enables searching for similar fragments of data profiles and identification of variables which significantly influence the results of the analysis of similarity. The approach is addressed to a broad group of chemists and specialists in similar fields.
Słowa kluczowe
Chemometrics; Visualization of similarity; Correlation coefficient; Data transformation.