Consecutive Retrieval Property Research Articles

Consecutive retrieval property—revisited

The connection between the consecutive retrieval property and interval graphs is explored. Necessary and sufficient conditions for the existence of the consecutive retrieval property are developed from the standpoint of graph theory. These conditions are based on a characterization of unit interval graphs developed in this paper.

On the Consecutive-Retrieval Problem

A $\{ 0,1\} $-matrix M has the consecutive-retrieval property if there exists a tree M such that the vertices of T are indexed on the rows of M and the columns of M are the incidence vectors of the vertex sets of paths of . If such a T exists, then T is a realization for M. In this paper, an $O(r^2 c)$ algorithm is presented to determine whether a given standard, $r \times c$ matrix has the consecutive-retrieval property and, if so, to construct a realization.

On Analyses of the Modified Versions of the Consecutive Retrieval File Organization

In information retrieval systems, the consecutive retrieval (CR) property enables the design of the system with a minimal search time and no redundant storage. However, the CR property cannot exist between every arbitrary query set and every record set unless we relax these restrictions. We use the variable-buffer quasi-CR (V-QCR) property scheme which tolerates variable buffer size in the main storage and several secondary storages. In secondary file organization, we propose two subschemes: 1) the relaxed CR (RCR) property subscheme which tolerates the duplication of records and multiple access, and 2) the CR property with dummy records (CR-D property) subscheme which tolerates the dummy records and the variable buffer size. For each proposed subscheme, we evaluate the trade-offs between the system redundancy and the loss of search time by rate-distortion theoretic approach. The result indicates that it is worthwhile to search for algorithms that will generate the secondary storage locations satisfying RCR and CR-D property subschemes, when the system size becomes sufficiently large.

Organization of clustered files for consecutive retrieval

This paper studies the problem of storing single-level and multilevel clustered files. Necessary and sufficient conditions for a single-level clustered file to have the consecutive retrieval property (CRP) are developed. A linear time algorithm to test the CRP for a given clustered file and to identify the proper arrangement of objects, if CRP exists, is presented. For the single-level clustered files that do not have CRP, it is shown that the problem of identifying a storage organization with minimum redundancy is NP-complete. Consequently, an efficient heuristic algorithm to generate a good storage organization for such files is developed. Furthermore, it is shown that, for certain types of multilevel clustered files, there exists a storage organization such that the objects in each cluster, for all clusters in each level of the clustering, appear in consecutive locations.

On the consecutive retrieval property for generalized binary queries

Dans cet article, on donne une limite inferieure sur la longueur d'une suite CR de vecteurs de V n pour l'ensemble de requetes {S 1 ,...,S n ,S 1 ,...,S n } et on donne aussi un algorithme pour construire une suite CR qui atteint cette limite

Algorithmic approach to the consecutive retrieval property

Ghosh's consecutive retrieval property (CR property) not only represents an elegant file organization, but also raises the problem of how to construct such a file with this property. Ghosh used ann ×m 0–1 incidence matrix, wheren is the number of records andm is the number of queries, as a tool for constructing a file with the CR property. In this paper the rows and columns of the incidence matrix are restricted to unique 0–1 patterns. It is found that such a unique incidence matrix cannot have the CR property if the number of rows is greater than 2m−1. This upper bound can be used to generatem(2m−1) columns, which form all the matrices with the CR property that may correspond to the given matrix. Two algorithms are presented which map the columns of the given incidence matrix to these columns with consecutive l's. A proposed implementation in terms of data base design is also presented.

Three-queries file organizations

The following combinatorial problem arising in file organization is considered: Given three sets M1, M2, M3 ⊆ X, find an arrangement of X such that each Mi is a segment of consecutive elements of X. Also some theorems extending the results of Ghosh concerning the two-dimensional consecutive retrieval property are proved. In particular, necessary and sufficient condition for a family of three sets to admit a two-dimensional organization is given.

Polynomial Complete Consecutive Information Retrieval Problems

A set of queries Q is said to have the consecutive retrieval property with respect to a set of records R if there exists an organization of the record set (without duplication of any record) such t...

Partition of a query set into minimal number of subsets having consecutive retrieval property

This paper is concerned with information retrieval. The basic problem is how to store large masses of data in such a way that whenever information regarding some particular aspect of the data is needed, such information is easily and efficiently retrieved. Work in this field is thus very important for organizations dealing with large classes of data. The consecutive retrieval (C-R) property defined by S.P. Ghosh is an important relation between a set of queries and a set of records. Its existence enables the design of information retrieval system with a minimal search time and no redundant storage in that the records can be organized in such a way that those pertinent to any query are stored in consecutive storage locations. The C-R property, however, can not exist between every arbitrary query set and every record set. A subset of the query set Q having the C-R property is called a C-R subset and a C-R subset having the maximum cardinality is called the maximal C-R subset. A partition of Q is called the C-R partition if every subset has the C-R property. A C-R partition with minimum number of subsets is called the minimal C-R partition. With respect to the set of all binary queries and the set of all binary records, it is shown that the maximal cardinality of a C-R subset is 2 l-1 where l is the number of attributes concerned. A combinatorial characterization of a maximal C-R subset is also given. A lower bound on the number of subsets in a C-R partition and several examples which attain the lower bound are given. A general procedure for obtaining a minimal C-R partition which attains the lower bound is given provided the number of attributes is even.

File organization: Consecutive storage of relevant records on drum-type storage

Certain structure relationships between a query set, a record set, and storage media provide an opportunity to organize the record set without redundancy on the storage media, in such a manner that all records pertinent to any query in the query set can be retrieved with minimum access time. This property between query sets and record sets has been studied for drum-type storage media. Sufficient conditions for such a property have been established. It has been shown that the two dimensional storage capability of the drum-type storage can be utilized to extend the class of query sets and record sets for which the consecutive retrieval property exists on a linear storage media.

On the Consecutive Retrieval Property in File Organization

The consecutive retrieval (CR) property has been defined as the property of a query that can be answered by the retrieval of consecutive records in a file. In this correspondence we add some observations about boundary conditions to Gosh's study of the CR property.

On the theory of consecutive storage of relevant records

A set of queries is said to have the consecutive retrieval property w.r.t. a set of records if all the records pertinent to any query belonging to the query set can be stored in consecutive storage locations. Some theorems have been established for query sets and record sets which have (or have not) the consecutive retrieval property. It has been shown that the set of all binary queries do not have the consecutive retrieval property w.r.t. the set of all binary records. The importance of nested queries in this context has been discussed.

File organization

The consecutive retrieval property is an important relation between a query set and record set. Its existence enables the design of an information retrieval system with a minimal search time and no redundant storage. Some important theorems on the consecutive retrieval property are proved in this paper. Conditions under which the consecutive retrieval property exists and remain invariant have been established. An outline for designing an information retrieval system based on the consecutive retrieval property is also discussed.