A signature file scheme based on multiple organizations for indexing very large text databases

Abstract

A new signature file method for accessing information from large databases containing both formatted and free text data is presented. The new method, called the multiorganizational scheme is proposed for indexing very large databases containing hundreds of thousands or possibly millions of records. With this method, records are grouped into blocks and signatures are formed for each block of records. These signatures are stored in a block descriptor file using a storage device called the bit slice organization.By forming multiple block descriptor files, each based on a possibly different grouping of records into blocks, it is possible to efficiently determine record matches on query. Both computational resultsbased on a mathematical model as well as experimental results using a library database are presented. These results show that the method provides effective access to large text databases.

Self-indexing inverted files for fast text retrieval

“…Multi-level signature file organisations reduce processing time by forming "super" signatures for blocks of records, so that record signatures for a block are investigated only if all query terms appear somewhere in the block [20,28]. While they reduce the amount of data transferred from disk during query evaluation, these methods do not reduce the size of the index.…”

An efficient signature-based strategy for supporting inexact filtering in information filtering systems

“…To save the storage of user profiles and filter documents much efficiently, profiles and documents are often represented as bitmaps in the filtering process. The Signature File (Faloutsos, 1985;Kent et al, 1990), the Bit-Slice File (Ishikawa et al, 1993), the S-tree (Deppisch, 1986) and the Signature Tree (Chen, 2005) are introduced.…”

“…Different strategies for the inexact match have been proposed, such as the Signature Files (Faloutsos, 1985;Kent, Sacks-Davis, & Ramamohanarao, 1990), the Bit-Slice Files (Ishikawa, Kitagawa, & Ohbo, 1993), the S-trees (Deppisch, 1986), and the Signature Trees (Chen, 2005). All of these strategies can be revised for the inexact filtering by changing the query process very easily.…”

Applications of n‐grams in textual information systems

“…The basic approach has been widely described (see, e.g. [69][70][71][72]) and we thus provide only a brief summary here. A word, or string, is represented by its constituent substrings, e.g.…”