Improved chromosome classification using monotonic functions of mahalanobis distance and the transportation method

Autor: Ilse Mitterreiter, Peter Kleinschmidt, Jim Piper
Rok vydání: 1994
Předmět:
Zdroj: ZOR Zeitschrift f�r Operations Research Mathematical Methods of Operations Research. 40:305-323
ISSN: 1432-5217
0340-9422
Popis: It is shown that the accuracy of chromosome classification constrained by class size can be improved over previously reported results by a combination of straightforward modifications to previously used methods. These are (i) the use of the logarithm of the Mahalanobis distance of an unknown chromosome's feature vector to estimated class mean vectors as the basis of the transportation method objective function, rather than the estimated likelihood; (ii) the use of all available features and full estimated covariance to compute the Mahalanobis distance, rather than a subset of features and the diagonal (variance) terms only; (iii) a modification to the way the transportation model deals with the constraint on the number of sex chromosomes in a metaphase cell; and (iv) the use of a newly discovered heuristic to weight off-diagonal elements of the covariance; this proved to be particularly valuable in cases where relatively few training examples were available to estimate covariance. The methods have been verified using 5 different sets of chromosome data.
Databáze: OpenAIRE
Externí odkaz: