Document Retrieval , Automatic 1 Elizabeth D . Liddy Center for Natural Language Processing School of Information Studies

Document Retrieval is the computerized process of producing a relevance ranked list of documents in response to an inquirer’s request by comparing their request to an automatically produced index of the documents in the system. Everyone uses such systems today in the form of web-based search engines. While evolving from a fairly small discipline in the 1940s, to a large, profitable industry today, the field has maintained a healthy research focus, supported by test collections and large-scale annual comparative tests of systems. A document retrieval system is comprised of three core modules: document processor, query analyzer, and matching function. There are several theoretical models on which document retrieval systems are based: Boolean, Vector Space, Probabilistic, and Language Model.