Now showing items 1-19 of 19

    • Aggregated 2D range queries on clustered points 

      Bernardo Roca, Guillermo de; Konow, Bernardo; Navarro, Gonzalo; Rodríguez Brisaboa, Nieves; 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. ...
    • Efficient and Compact Representations of Some Non-canonical Prefix-Free Codes 

      Fariña, Antonio; Gagie, Travis; Manzini, Giovanni; Navarro, Gonzalo; Ordóñez, Alberto (Springer, 2016-09-21)
      [Abstract] For many kinds of prefix-free codes there are efficient and compact alternatives to the traditional tree-based representation. Since these put the codes into canonical form, however, they can only be used when ...
    • Compact Trip Representation over Networks 

      Brisaboa, Nieves R.; Fariña, Antonio; Galaktionov, Daniil; Rodríguez, M. Andrea (Springer, 2016-09-21)
      [Abstract] We present a new Compact Trip Representation ( CTRCTR ) that allows us to manage users’ trips (moving objects) over networks. These could be public transportation networks (buses, subway, trains, and so on) where ...
    • 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 ...
    • Efficient Representation of Multidimensional Data over Hierarchical Domains 

      Brisaboa, Nieves R.; Cerdeira Pena, Ana Belén; López López, Narciso; Navarro, Gonzalo; Penabad, Miguel R.; Silva-Coira, Fernando (Springer, 2016-09-21)
      [Abstract] We consider the problem of representing multidimensional data where the domain of each dimension is organized hierarchically, and the queries require summary information at a different node in the hierarchy of ...
    • Parallel construction of wavelet trees on multicore architectures 

      Fuentes Sepúlveda, José; Elejalde, Erick; Ferres, Leo; Seco, Diego (Springer U K, 2016-10-05)
      [Abstract] The wavelet tree has become a very useful data structure to efficiently represent and query large volumes of data in many different domains, from bioinformatics to geographic information systems. One problem ...
    • Grammar compressed sequences with rank/select support 

      Ordóñez, Alberto; Navarro, Gonzalo; Brisaboa, Nieves R. (Elsevier BV, 2016-10-14)
      [Abstract] Sequence representations supporting not only direct access to their symbols, but also rank/select operations, are a fundamental building block in many compressed data structures. Several recent applications need ...
    • A succinct data structure for self-indexing ternary relations 

      Álvarez García, Sandra; De Bernardo Roca, Guillermo; Rodríguez Brisaboa, Nieves; 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 ...
    • Universal indexes for highly repetitive document collections 

      Claude, Francisco; Fariña, Antonio; Martínez Prieto, Miguel A.; Navarro, Gonzalo (Elsevier Ltd, 2016-11)
      [Abstract] Indexing highly repetitive collections has become a relevant problem with the emergence of large repositories of versioned documents, among other applications. These collections may reach huge sizes, but are ...
    • A new method to index and store spatio-temporal data 

      Bernardo Roca, 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, ...
    • Navigational Rule Derivation: An algorithm to determine the effect of traffic signs on road networks 

      Galaktionov, Daniil; Luaces, Miguel R.; Places, Ángeles S. (2016-11-17)
      [Abstract] In this paper we present an algorithm to build a road network map enriched with traffic rules such as one-way streets and forbidden turns, based on the interpretation of already detected and classified traffic ...
    • Design of Mutation Operators for Testing Geographic Information Systems 

      Alvarado, Suilen H. (M D P I AG, 2019-08-06)
      [Abstract] In this article, we propose the definition of specific mutation operators for testing Geographic Information Systems. We describe the process for applying the operators and generating mutants, and present a case ...
    • 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 ...
    • Improved Compressed String Dictionaries 

      Brisaboa, Nieves R.; Cerdeira Pena, Ana Belén; De Bernardo Roca, Guillermo; Navarro, Gonzalo (ACM, 2019-11-03)
      [Abstract] We introduce a new family of compressed data structures to efficiently store and query large string dictionaries in main memory. Our main technique is a combination of hierarchical Front-coding with ideas from ...
    • Efficient processing of raster and vector data 

      Silva-Coira, Fernando; Paramá, José R.; Ladra, Susana; López, Juan R.; Gutiérrez, Gilberto (Public Library of Science, 2020-01-10)
      [Abstract] In this work, we propose a framework to store and manage spatial data, which includes new efficient algorithms to perform operations accepting as input a raster dataset and a vector dataset. More concretely, we ...
    • Compressed Data Structures for Binary Relations in Practice 

      Quijada Fuentes, Carlos; Penabad, Miguel R.; Ladra, Susana; Gutiérrez Retamal, Gilberto (Institute of Electrical and Electronics Engineers, 2020-01-31)
      [Abstract] Binary relations are commonly used in Computer Science for modeling data. In addition to classical representations using matrices or lists, some compressed data structures have recently been proposed to represent ...
    • An Action Research for Improving the Sustainability Assessment Framework Instruments 

      Condori-Fernandez, Nelly; Lago, Patricia; Rodríguez Luaces, Miguel; Places, Ángeles S. (M D P I AG, 2020-02-24)
      [Abstract] In the last years, software engineering researchers have defined sustainability as a quality requirement of software, but not enough effort has been devoted to develop new methods/techniques to support the ...
    • Towards a non-functional requirements discovery approach for persuasive systems 

      Condori-Fernandez, Nelly; Araujo, Joao; Catala, Alejandro; Lago, Patricia (Association for Computing Machinery, 2020-03-30)
      [Abstract] A number of software systems that attempt to help people achieve behavior change have been proposed in various domains such as health and wellness. However, sometimes, such systems have failed to provide a ...
    • Automatic group-wise whole-brain short association fiber bundle labeling based on clustering and cortical surface information 

      Vázquez, Andrea; López-López, Narciso; Houenou, Josselin; Poupon, Cyril; Mangin, Jean-François; Ladra, Susana; Guevara, Pamela (BioMed Central Ltd., 2020-06-03)
      [Abstract] Background Diffusion MRI is the preferred non-invasive in vivo modality for the study of brain white matter connections. Tractography datasets contain 3D streamlines that can be analyzed to study the main ...