• Boosting Perturbation-Based Iterative Algorithms to Compute the Median String 

      Mirabal, Pedro; Abreu Salas, José Ignacio; Seco, Diego; Pedreira, Óscar; Chávez, Edgar (IEEE, 2021)
      [Abstract] The most competitive heuristics for calculating the median string are those that use perturbation-based iterative algorithms. Given the complexity of this problem, which under many formulations is NP-hard, the ...
    • 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 ...
    • 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 ...
    • Multilevel Modeling of Geographic Information Systems Based on International Standards 

      Alvarado, Suilen H.; Cortiñas, Alejandro; Rodríguez Luaces, Miguel; Pedreira, Óscar; Saavedra Places, Ángeles (SpringerLink, 2021)
      [Abstract] Even though different applications based on Geographic Information Systems (GIS) provide different features and functions, they all share a set of common concepts (e.g., spatial data types, operations, services), ...
    • 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 ...
    • Take one for the team: on the time efficiency of application-level buffer-aided relaying in edge cloud communication 

      Li, Zheng; Millar-Bilbao, Francisco; Rojas-Durán, Gonzalo; Ladra, Susana (Springer, 2021-03-12)
      [Abstract] Background Adding buffers to networks is part of the fundamental advance in data communication. Since edge cloud computing is based on the heterogeneous collaboration network model in a federated environment, ...
    • Succinct Encoding of Binary Strings Representing Triangulations 

      Fuentes Sepúlveda, José; Seco, Diego; Viaña, Raquel (Springer, 2021-11)
      [Abstract]: We consider the problem of designing a succinct data structure for representing the connectivity of planar triangulations. The main result is a new succinct encoding achieving the information-theory optimal ...
    • Compact and indexed representation for LiDAR point clouds 

      Ladra, Susana; Rodríguez Luaces, Miguel; Paramá, José R.; Silva-Coira, Fernando (Taylor & Francis, 2022)
      [Abstract]: LiDAR devices are capable of acquiring clouds of 3D points reflecting any object around them, and adding additional attributes to each point such as color, position, time, etc. LiDAR datasets are usually large, ...
    • Combining Multiple Granularity Variability in a Software Product Line Approach for Web Engineering 

      Horcas Aguilera, José Miguel; Cortiñas, Alejandro; Fuentes, Lidia; Rodríguez Luaces, Miguel (Elsevier, 2022)
      [Abstract] Context: Web engineering involves managing a high diversity of artifacts implemented in different languages and with different levels of granularity. Technological companies usually implement variable artifacts ...
    • Modeling the Number of People Infected With SARS-COV-2 From Wastewater Viral Load in Northwest Spain 

      Vallejo, J. A.; Trigo Tasende, Noelia; Rumbo-Feal, Soraya; Conde-Pérez, Kelly; López-Oriona, Ángel; Barbeito, Inés; Vaamonde, Manuel; Tarrío-Saavedra, Javier; Reif López, Rubén; Ladra, Susana; Rodiño-Janeiro, Bruno Kotska; Nasser-Ali, Mohammed; Cid, Ángeles; Veiga, María Carmen; Acevedo, Antón; Lamora, Carlos; Bou, Germán; Cao, Ricardo; Poza, Margarita (Elsevier, 2022)
      [Abstract] The quantification of the SARS-CoV-2 RNA load in wastewater has emerged as a useful tool to monitor COVID–19 outbreaks in the community. This approach was implemented in the metropolitan area of A Coruña (NW ...
    • Graph Compression for Adjacency-Matrix Multiplication 

      Francisco, Alexandre P.; Gagie, Travis; Köppl, Dominik; Ladra, Susana; Navarro, Gonzalo (Springer, 2022)
      [Abstract] Computing the product of the (binary) adjacency matrix of a large graph with a real-valued vector is an important operation that lies at the heart of various graph analysis tasks, such as computing PageRank. In ...
    • Proyecto COVIDBENS. Seguimiento de la pandemia de COVID-19 en aguas residuales del área metropolitana de A Coruña 

      Trigo-Tasende, Noelia; Vaamonde, Manuel; Paramá, José R.; Tarrío-Saavedra, Javier; López-de-Ulibarri, Ignacio; Vallejo, J.A.; Ladra, Susana; Cao, Ricardo; Poza, Margarita (Sociedad Española de Sanidad Ambiental, 2022-05-18)
      [Resumen]: El virus SARS-CoV-2 está compuesto por una nucleocápside que engloba su material genético y la proteína N, rodeada por una membrana bilipídica, que contiene las proteínas M y E, y una corona de espinas, que ...
    • New machine learning approaches for real-life human activity recognition using smartphone sensor-based data 

      García-González, Daniel; Rivero, Daniel; Fernández-Blanco, Enrique; Rodríguez Luaces, Miguel (Elsevier B.V., 2023)
      [Abstract]: In recent years, mainly due to the application of smartphones in this area, research in human activity recognition (HAR) has shown a continuous and steady growth. Thanks to its wide range of sensors, its size, ...
    • Navigating planar topologies in near-optimal space and time 

      Fuentes Sepúlveda, José; Navarro, Gonzalo; Seco, Diego (Elsevier B.V., 2023-02)
      [Abstract]: We show that any embedding of a planar graph can be encoded succinctly while efficiently answering a number of topological queries near-optimally. More precisely, we build on a succinct representation that ...
    • 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/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 ...
    • Map algebra on raster datasets represented by compact data structures 

      Silva-Coira, Fernando; Paramá, José R.; Ladra, Susana (John Wiley and Sons, 2023-06)
      [Abstract]: The increase in the size of data repositories has forced the design of new computing paradigms to be able to process large volumes of data in a reasonable amount of time. One of them is in-memory computing, ...
    • 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 ...
    • 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 ...
    • 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 ...