Processing the boundary regions of three-way clustering based on the kNN algorithm.
: a set of objects , the cluster centers , the positive region , boundary region , and the optimal value of k.
: the updated positive region and boundary region
: calculate the distance between and other objects, where ;
: find the region where the k points with the smallest distance are located;
: is the number of k objects in the positive region of class , where . is the number of k objects in the boundary region, and . If there is only one cluster , such that , then and else
: repeat Steps 1–3 until all boundary objects have been computed.
