Scalable system for expectation maximization clustering of large databases

摘要

In one exemplary embodiment the invention provides a data mining system for use in finding clusters of data items in a database or any other data storage medium. Before the data evaluation begins a choice is made of the number M of models to be explored, and the number of clusters (K) of clusters within each of the M models. The clusters are used in categorizing the data in the database into K different clusters within each model. An initial set of estimates for a data distribution of each model to be explored is provided. Then a portion of the data in the database is read from a storage medium and brought into a rapid access memory buffer whose size is determined by the user or operating system depending on available memory resources. Data contained in the data buffer is used to update the original model data distributions in each of the K clusters over all M models. Some of the data belonging to a cluster is summarized or compressed and stored as a reduced form of the data representing sufficient statistics of the data. More data is accessed from the database and the models are updated. An updated set of parameters for the clusters is determined from the summarized data (sufficient statistics) and the newly acquired data. Stopping criteria are evaluated to determine if further data should be accessed from the database.