S.No

Clustering Method

(Existing)

Drawbacks Identified

Root Cause

1.

Pairwise Nearest Neighbor

Method

・ Slowness.

・ Time complexity-O(N³)

・ Pairwise merging of data object

lead to slowness

2.

Upper Approximation Based Rough Set Clustering

・ Poor cluster validity index value

・ Possibility factor lead to reductionin cluster tightness

3.

K-Means Clustering

・ Slowness.

・ Formation of loose clusters.

・ Need to specify the number of clusters.

・ Reassignment of cluster objects lead to slowness

・ Existence of outliers affect the cluster

・ Mean value and therefore tightness.

4.

Fuzzy C Means Clustering

・ Poor cluster validity index

・ Fuzziness in data affects cluster density