Clustering via Ant Colonies: Parameter Analysis and Improvement of the Algorithm
This is an incremental improvement for clustering tasks, potentially benefiting data analysts.
The authors tackled clustering by proposing an ant colony optimization method that minimizes intra-variance, with improvements from applying K-means in some iterations. They reported encouraging results on benchmark datasets after parameter tuning.
An ant colony optimization approach for partitioning a set of objects is proposed. In order to minimize the intra-variance, or within sum-of-squares, of the partitioned classes, we construct ant-like solutions by a constructive approach that selects objects to be put in a class with a probability that depends on the distance between the object and the centroid of the class (visibility) and the pheromone trail; the latter depends on the class memberships that have been defined along the iterations. The procedure is improved with the application of K-means algorithm in some iterations of the ant colony method. We performed a simulation study in order to evaluate the method with a Monte Carlo experiment that controls some sensitive parameters of the clustering problem. After some tuning of the parameters, the method has also been applied to some benchmark real-data sets. Encouraging results were obtained in nearly all cases.