Comparison of five clustering algorithms to classify phytoplankton from flow cytometry data.
BACKGROUND
Artificial neural networks (ANNs) have been shown to be valuable in the analysis of analytical flow cytometric (AFC) data in aquatic ecology. Automated extraction of clusters is an important first stage in deriving ANN training data from field samples, but AFC data pose a number of challenges for many types of clustering algorithm. The fuzzy k-means algorithm recently has been extended to address nonspherical clusters with the use of scatter matrices. Four variants were proposed, each optimizing a different measure of clustering "goodness."


METHODS
With AFC data obtained from marine phytoplankton species in culture, the four fuzzy k-means algorithm variants were compared with each other and with another multivariate clustering algorithm based on critical distances currently used in flow cytometry.


RESULTS
One of the algorithm variants (adaptive distances, also known as the Gustafson--Kessel algorithm) was found to be robust and reliable, whereas the others showed various problems.


CONCLUSIONS
The adaptive distances algorithm was superior in use to the clustering algorithms against which it was tested, but the problem of automatic determination of the number of clusters remains to be addressed.
Wilkins
M F
MF
Cardiff School of Biosciences, Cardiff, United Kingdom.
Hardy
S A
SA
Boddy
L
L
Morris
C W
CW
D000465:Algorithms; D001330:Electronic Data Processing; D005434:Flow Cytometry / Q000379:methods*; D005544:Forecasting; D016571:Neural Networks, Computer; D010839:Phytoplankton / Q000145:classification*; D012106:Research