• A succinct data structure for self-indexing ternary relations 

      Álvarez García, Sandra; Bernardo, Guillermo de; Brisaboa, Nieves R.; Navarro, Gonzalo (Elsevier BV, 2016-10-27)
      [Abstract] The representation of binary relations has been intensively studied and many different theoretical and practical representations have been proposed to answer the usual queries in multiple domains. However, ternary ...
    • 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. ...
    • Classic distance join queries using compact data structures 

      Bernardo, Guillermo de; Penabad, Miguel R.; Corral, Antonio; Brisaboa, Nieves R. (Elsevier, 2024-07)
      [Abstract]: Distance-based Join Queries (DJQs) have multiple applications in spatial databases, Geographic Information Systems, and other areas. The K Closest Pairs Query (KCPQ) and the 𝜀� Distance Join Query (𝜀� DJQ) ...
    • Compressed and queryable self-indexes for RDF archives 

      Cerdeira-Pena, Ana; Bernardo, Guillermo de; Fariña, Antonio; Fernández, Javier D.; Martínez-Prieto, Miguel A. (Springer Nature, 2023-08)
      [Abstract]: RDF compression and querying are consolidated topics in the Web of Data, with a plethora of solutions to efficiently store and query static datasets. However, as RDF data changes along time, it becomes necessary ...
    • 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 ...
    • 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 ...