Write short notes on clustering.

Clustering :-

• Clustering is the process of grouping a set of data objects into multiple groups or clusters so that objects within a cluster have high similarity, but are very dissimilar to objects in other clusters.

• Dissimilarities and similarities are assessed based on the attribute values describing the objects and often involve distance measures.

• The "quality" of a cluster may be represented by its diameter, the maximum distance between any two objects in the cluster.

• Centroid distance is an alternative measure of cluster quality and is defined as the average distance of each cluster object from the cluster centroid.

• Cluster analysis or simply clustering is the process of partitioning a set of data objects (or observations) into subsets.

• The set of clusters resulting from a cluster analysis can be referred to as a clustering.

• Clustering can lead to the discovery of previously unknown groups within the data.

• Cluster analysis has been widely used in many applications such as business intelligence, image pattern recognition, Web search, biology, and security.