With the exponential growth of documents available to us on the web, the requirement for an effective technique to retrieve the most relevant document matching a given search query has become critical. The field of Information Retrieval deals with the problem of document similarity to retrieve desired information from a large amount of data. Various models and similarity measures have been proposed to determine the extent of similarity between two objects. The objective of this paper is to summarize the entire process, looking into some of the most well-known algorithms and approaches to match a query text against a set of indexed documents.

The automated categorization (classification) of texts into predefined categories is one of the widely explored fields of research in text mining. Now-a-days, availability of digital data is very high, and to manage them in predefined categories has become a challenging task. Machine learning technique is an approach by which we can train automated classifier to classify the documents with minimum human assistance. This paper discusses the Naïve Bayes, Rocchio, k-Nearest Neighborhood and Support Vector Machine methods within machine learning paradigm for automated text categorization of given documents in predefined categories.

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