• Aggregated 2D range queries on clustered points 

      Bernardo, Guillermo de; Konow, Bernardo; Navarro, Gonzalo; Brisaboa, Nieves R.; Seco, Diego (Elsevier Ltd, 2016-09)
      [Abstract] Efficient processing of aggregated range queries on two-dimensional grids is a common requirement in information retrieval and data mining systems, for example in Geographic Information Systems and OLAP cubes. ...
    • Compact representations of spatial hierarchical structures with support for topological queries 

      Fuentes Sepúlveda, José; Gatica, Diego; Navarro, Gonzalo; Rodríguez, M. Andrea; Seco, Diego (Elsevier Inc., 2023-06)
      [Abstract]: Among different spatial data models, the topological model for spatial regions explicitly represents common boundaries. This model pursues the efficiency of topology-related queries and the elimination of data ...
    • Energy Consumption in Compact Integer Vectors: A Study Case 

      Fuentes Sepúlveda, José; Ladra, Susana (Institute of Electrical and Electronics Engineers, 2019-10-25)
      [Abstract] In the field of algorithms and data structures analysis and design, most of the researchers focus only on the space/time trade-off, and little attention has been paid to energy consumption. Moreover, most of the ...
    • Extending general compact querieable representations to GIS applications 

      Brisaboa, Nieves R.; Cerdeira-Pena, Ana; Bernardo, Guillermo de; Navarro, Gonzalo; Pedreira, Óscar (Elsevier, 2020-01)
      [Abstract]: The raster model is commonly used for the representation of images in many domains, and is especially useful in Geographic Information Systems (GIS) to store information about continuous variables of the space ...
    • Faster compressed quadtrees 

      Bernardo, Guillermo de; Gagie, Travis; Ladra, Susana; Navarro, Gonzalo; Seco, Diego (Elsevier B.V., 2023-02)
      [Abstract]: Real-world point sets tend to be clustered, so using a machine word for each point is wasteful. In this paper we first show how a compact representation of quadtrees using O(1) bits per node can break this bound ...
    • 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 ...
    • Space-Efficient Representations of Raster Time Series 

      Silva-Coira, Fernando; Paramá, José R.; Bernardo, Guillermo de; Seco, Diego (Elsevier, 2021)
      [Abstract] Raster time series, a.k.a. temporal rasters, are collections of rasters covering the same region at consecutive timestamps. These data have been used in many different applications ranging from weather forecast ...
    • Space/time-efficient RDF stores based on circular suffix sorting 

      Brisaboa, Nieves R.; Cerdeira-Pena, Ana; Bernardo, Guillermo de; Fariña, Antonio; Navarro, Gonzalo (Springer Nature, 2023-03)
      [Abstract]: The resource description framework (RDF) has gained popularity as a format for the standardized publication and exchange of information in the Web of Data. In this paper, we introduce RDFCSA, a compressed ...
    • 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 ...