Clustering
Unsupervised learning method used to group a set of objects in such a way that objects in the same group (called a cluster) are more similar to each other than to those in other groups.
Clustering is fundamental in data analysis and pattern recognition, serving as a method for discovering structure in data. It's widely used in various domains, such as market research, image segmentation, social network analysis, and bioinformatics, to partition data sets into subsets or clusters. The goal is to maximize the similarity of objects within a cluster and maximize the dissimilarity between objects in different clusters. Key algorithms include K-means, hierarchical clustering, and DBSCAN, each with unique approaches to defining clusters and assessing data points' membership within those clusters.
The concept of clustering has roots in early statistical methods, but it gained prominence as a computer-based method in the 1950s and 1960s with the advent of more sophisticated data collection and analysis tools.
While it's challenging to pinpoint a single contributor to the development of clustering, some key figures in the early stages include R.A. Fisher and J. MacQueen. Fisher's work on linear discriminant analysis in the 1930s laid groundwork relevant to clustering, and MacQueen's introduction of the K-means algorithm in 1967 was a significant milestone in clustering techniques.