Now showing items 1-11 of 11

    • 3DGraCT: A Grammar-Based Compressed Representation of 3D Trajectories 

      Brisaboa, Nieves R.; Gómez-Brandón, Adrián; Martínez-Prieto, Miguel A.; Paramá, José R. (Springer, 2018)
      [Abstract]: Much research has been published about trajectory management on the ground or at the sea, but compression or indexing of flight trajectories have usually been less explored. However, air traffic management is ...
    • A New Method to Index and Store Spatio-Temporal Data 

      Bernardo, Guillermo de; Casares, Ramón; Gómez-Brandón, Adrián; Paramá, José R. (2016-11-16)
      [Abstract] We propose a data structure that stores, in a compressed way, object trajectories, which at the same time, allow to efficiently response queries without the need to decompress the data. We use a data structure, ...
    • An index for moving objects with constant-time access to their compressed trajectories 

      Brisaboa, Nieves R.; Gagie, Travis; Gómez-Brandón, Adrián; Navarro, Gonzalo; Paramá, José R. (Taylor & Francis, 2021)
      [Abstract]: As the number of vehicles and devices equipped with GPS technology has grown explosively, an urgent need has arisen for time- and space-efficient data structures to represent their trajectories. The most commonly ...
    • GraCT: A Grammar Based Compressed Representation of Trajectories 

      Brisaboa, Nieves R.; Gómez-Brandón, Adrián; Navarro, Gonzalo; Paramá, José R. (Springer, 2016-09-21)
      [Abstract] We present a compressed data structure to store free trajectories of moving objects (ships over the sea, for example) allowing spatio-temporal queries. Our method, GraCT, uses a k2k2 -tree to store the absolute ...
    • GraCT: A Grammar-based Compressed Index for Trajectory Data 

      Brisaboa, Nieves R.; Gómez-Brandón, Adrián; Navarro, Gonzalo; Paramá, José R. (Elsevier Ltd, 2019)
      [Abstract]: We introduce a compressed data structure for the storage of free trajectories of moving objects that efficiently supports various spatio-temporal queries. Our structure, dubbed GraCT, stores the absolute positions ...
    • Lossless Compression of Industrial Time Series With Direct Access 

      Gómez-Brandón, Adrián; Paramá, José R.; Villalobos, Kevin; Illarramendi, Arantza; Brisaboa, Nieves R. (Elsevier, 2021)
      [Abstract] The new opportunities generated by the data-driven economy in the manufacturing industry have causedmany companies opt for it. However, the size of time series data that need to be captured creates theproblem ...
    • Optimizing RPQs over a compact graph representation 

      Arroyuelo, Diego; Gómez-Brandón, Adrián; Hogan, Aidan; Navarro, Gonzalo; Rojas-Ledesma, Javiel (Springer, 2023-09-07)
      [Absctract]: We propose techniques to evaluate regular path queries (RPQs) over labeled graphs (e.g., RDF). We apply a bit-parallel simulation of a Glushkov automaton representing the query over a ring: a compact ...
    • Stronger compact representations of object trajectories 

      Gómez-Brandón, Adrián; Navarro, Gonzalo; R. Paramá, José; Brisaboa, Nieves R.; Gagie, Travis (Taylor & Francis, 2024-02-13)
      [Absctract]: GraCT and ContaCT were the first compressed data structures to represent object trajectories, demonstrating that it was possible to use orders of magnitude less space than classical indexes while staying ...
    • The Ring: Worst-case Optimal Joins in Graph Databases using (Almost) No Extra Space 

      Arroyuelo, Diego; Gómez-Brandón, Adrián; Hogan, Aidan; Navarro, Gonzalo; Reutter, Juan; Rojas-Ledesma, Javiel; Soto, Adrián (Association for Computing Machinery (ACM), 2024-03-23)
      [Absctract]: We present an indexing scheme for triple-based graphs that supports join queries in worst-case optimal (wco) time within compact space. This scheme, called a ring, regards each triple as a cyclic string of ...
    • Two-Dimensional Block Trees 

      Brisaboa, Nieves R.; Gagie, Travis; Gómez-Brandón, Adrián; Navarro, Gonzalo (Oxford University Press, 2024-01)
      [Absctract]: The Block Tree is a data structure for representing repetitive sequences in compressed space, which reaches space comparable with that of Lempel–Ziv compression while retaining fast direct access to any position ...
    • Worst-Case-Optimal Similarity Joins on Graph Databases 

      Arroyuelo, Diego; Bustos, Benjamin; Gómez-Brandón, Adrián; Hogan, Aidan; Navarro, Gonzalo; Reutter, Juan (Association for Computing Machinery (ACM), 2024-03-06)
      [Absctract]: We extend the concept of worst-case optimal equijoins in graph databases to the case where some nodes are required to be within the k-nearest neighbors (kNN) of others under some similarity function. We model ...