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Multi-way distance joins queries in spatial databases / A. Corral in Geoinformatica, vol 8 n° 4 (December 2004)  

Public [article]  inGeoinformatica > vol 8 n° 4 (December 2004) . - pp 373 - 402 Titre : Multi-way distance joins queries in spatial databases Type de document : Article/Communication Auteurs : A. Corral, Auteur ; Y. Manolopoulos, Auteur ; Y. Theodoridis, Auteur ; M. Vassilakopoulos, Auteur Année de publication : 2004 Article en page(s) : pp 373 - 402 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] arbre-R [Termes IGN] base de données localisées [Termes IGN] graphe [Termes IGN] jointure spatiale [Termes IGN] requête spatiale Résumé : (Auteur) Let a tuple of n objects obeying a query graph (QG) be called the n-tuple. The "Ddistance-value" of this n-tuple is the value of a linear function of distances of the n objects that make up this n-tuple, according to the edges of the QG. This paper addresses the problem of finding the K n-tuples between n spatial datasets that have the smallest Ddistance-values, the so-called K-multi-way distance join query (K-MWDJQ), where each set is indexed by an R-tree-based structure. This query can be viewed as an extension of K-closest-pairs query (K-CPQ) for n inputs. In addition, a recursive non-incremental branch-and-bound algorithm following a depth-first search for processing synchronously all inputs without producing any intermediate result is proposed. Enhanced pruning techniques are also applied to n R-trees nodes in order to reduce the total response time and the number of distance computations of the query. Due to the exponential nature of the problem, we also propose a time-based approximate version of the recursive algorithm that combines approximation techniques to adjust the quality of the result and the global processing time. Finally, we give a detailed experimental study of the proposed algorithms using real spatial datasets, highlighting their performance and the quality of the approximate results. Numéro de notice : A2004-393 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/B:GEIN.0000040832.25622.8d En ligne : https://doi.org/10.1023/B:GEIN.0000040832.25622.8d Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26920 [article]

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Algorithms for joining R-trees and linear region quadtrees / A. Corral (20/07/1999)  

Public contenu dans Advances in spatial data bases, SSD '99, 6th International Symposium, Hong Kong, China, July 20-23, 1999 / Ralf Hartmut Güting (1999)   Titre : Algorithms for joining R-trees and linear region quadtrees Type de document : Article/Communication Auteurs : A. Corral, Auteur ; M. Vassilakopoulos, Auteur ; Y. Manolopoulos, Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 20/07/1999 Conférence : SSD 1999, 6th International Symposium Advances in spatial data bases 20/07/1999 23/07/1999 Hong Kong Chine Proceedings Springer Importance : pp 251 - 269 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] accès aux données localisées [Termes IGN] arbre quadratique [Termes IGN] arbre-R [Termes IGN] base de données localisées [Termes IGN] jointure spatiale [Termes IGN] requête spatiale Résumé : (Auteur) The family of R-trees is suitable for storing various kinds of multidimensional objects and is considered an excellent choice for indexing a spatial database. Region Quadtrees are suitable for storing 2-dimensional regional data and their linear variant is used in many Geographical Information Systems for this purpose. In this report, we present five algorithms suitable for processing join queries between these two successful, although very different, access methods. Two of the algorithms axe based on heuristics that aim at minimizing I/O cost with a limited amount of main memory. We also present the results of experiments performed with real data that compare the I/O performance of these algorithms. Numéro de notice : C1999-060 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Communication DOI : 10.1007/3-540-48482-5_16 En ligne : https://doi.org/10.1007/3-540-48482-5_16 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65826