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Πλοήγηση ανά Θέμα "Synthetic datasets"

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    • Algorithms for processing the group K nearest-neighbor query on distributed frameworks 

      Moutafis P., García-García F., Mavrommatis G., Vassilakopoulos M., Corral A., Iribarne L. (2021)
      Given two datasets of points (called Query and Training), the Group (K) Nearest-Neighbor (GKNN) query retrieves (K) points of the Training with the smallest sum of distances to every point of the Query. This spatial query ...

    • Efficient computation of containment and complementarity in RDF data cubes 

      Meimaris M., Papastefanatos G., Anagnostopoulos I., Vassiliadis P. (2016)
      Multidimensional data are published in the web of data under common directives, such as the Resource Description Framework (RDF). The increasing volume and diversity of these data pose the challenge of finding relations ...

    • Extended characteristic sets: Graph indexing for SPARQL Query Optimization 

      Meimaris M., Papastefanatos G., Mamoulis N., Anagnostopoulos I. (2017)
      SPARQL query execution in state of the art RDF engines depends on, and is often limited by the underlying storage and indexing schemes. Typically, these systems exhaustively store permutations of the standard three-column ...

    • The K group nearest-neighbor query on non-indexed RAM-resident data 

      Roumelis G., Vassilakopoulos M., Corral A., Manolopoulos Y. (2016)
      Data sets that are used for answering a single query only once (or just a few times) before they are replaced by new data sets appear frequently in practical applications. The cost of buiding indexes to accelerate query ...

    • Plane-sweep algorithms for the K Group Nearest-Neighbor Query 

      Roumelis, G.; Vassilakopoulos, M.; Corral, A.; Manolopoulos, Y. (2015)
      One of the most representative and studied queries in Spatial Databases is the (K) Nearest-Neighbor (NNQ), that discovers the (K) nearest neighbor(s) to a query point. An extension that is important for practical applications ...

    • The xbr+-tree: An efficient access method for points 

      Roumelis G., Vassilakopoulos M., Loukopoulos T., Corral A., Manolopoulos Y. (2015)
      Spatial indexes, such as those based on Quadtree, are important in spatial databases for efficient execution of queries involving spatial constraints. In this paper, we present improvements of the xBR-tree (a member of the ...