Permutation Based Algorithm Improved by Classes for Similarity Searching



Document title: Permutation Based Algorithm Improved by Classes for Similarity Searching
Journal: Computación y sistemas
Database:
System number: 000560669
ISSN: 1405-5546
Authors: 1
2
1
Institutions: 1Universidad Michoacana de San Nicolás Hidalgo, Facultad de Ciencias Físico Matemáticas, México
2Universidad Michoacana de San Nicolás Hidalgo, Facultad de Ingeniería Eléctrica, México
Year:
Season: Ene-Mar
Volumen: 26
Number: 1
Pages: 71-79
Country: México
Language: Inglés
English abstract Similarity searching is the most important task in multimedia databases, It consists in retrieving the most similar elements to a given query from a database, knowing that an element identical to the query would not be found. Dissimilarity between objects is measured with a distance function (usually expensive to compute), this allows approaching this problem with a metric space. Many algorithms have been designed to address this problem, in particular, the Permutation Based index has shown an unbeatable performance. This technique uses reference objects to determine a string for each element in the database that is a permutation of the same string. However, Huge databases and the memory required for these indexes make this problem a real challenge. In this paper, we present an improvement to the first approach where classes of reference objects were used instead of single references. In this paper, a new way to choose these classes is proposed and a new way to evaluate similarity between permutations. Our experiments show that we can avoid distance evaluations up to 90% with respect to the original technique, and up to 80% to the first approach.
Keyword: Similarity searching,
Metric spaces,
Pattern recognition,
Nearest neighbor
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