7.5 Clustering algorithms 313
similarity measure with the points already in the clusters. The computation
will be expensive. In addition, the density-search technique requires users
to set the threshold values. The threshold setting may not be natural and is
relatively difficult since the number of final clusters to be formed depends
on this value. Thus, as a method for clustering a large database, the density-
search technique may not be as efficient as the k-means algorithm.
7.5.5 Association Rule Algorithms
Association rules identify frequently used patterns of information in a data-
base that consists of non-transaction data. In this section, we study an algo-
rithm that deals with association rules for clustering. The algorithm ...