Score region algebra : a flexible framework for structured information retrieval

Approximately three decades ago researchers realized that they would have to structure data to be able to store and access large amounts of data streams that were produced each day. As a result, database management systems were designed and developed, used to keep the data in one place and for finding relevant information in this data. On the other hand, a large amount of textual documents was still stored and accessed in unstructured format. Retrieval of such textual documents, containing relevant information with respect to a user query, has been an open research question studied in the information retrieval area for half a century. Information retrieval studies resulted in numerous retrieval models and retrieval systems whose goal is to rank relevant documents according to their estimated rel- evance to a user query. Although having similar goals research areas of databases and information retrieval developed mostly independently from each other. Recently, the new `wave of documents' is `threatening' to bring these two areas closer to each other.