Now showing items 1-13 of 13

    • Aggregation languages for moving object and places of interest 

      Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel (2008)
      "We address aggregate queries over GIS data and moving object data, where non-spatial information is stored in a data warehouse. We propose a formal data model and query language to express complex aggregate queries. Next, ...
    • An algebra for OLAP 

      Kuijpers, Bart; Vaisman, Alejandro Ariel (2017)
      "Online Analytical Processing (OLAP) comprises tools and algorithms that allow querying multidimensional databases. It is based on the multidimensional model, where data can be seen as a cube, where each cell contains one ...
    • Analytical queries on semantic trajectories using graph databases 

      Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel (2019-10)
      "This article studies the analysis of moving object data collected by location-aware devices, such as GPS, using graph databases. Such raw trajectories can be transformed into so-called semantic trajectories, which are ...
    • Data quality in a big data context 

      Arolfo, Franco A.; Vaisman, Alejandro Ariel (2018)
      "In each of the phases of a Big Data analysis process, data quality (DQ) plays a key role. Given the particular characteristics of the data at hand, the traditional DQ methods used for relational databases, based on quality ...
    • Efficient analytical queries on semantic web data cubes 

      Etcheverry, Lorena; Vaisman, Alejandro Ariel (2017-12)
      "The amount of multidimensional data published on the semantic web (SW) is constantly increasing, due to initiatives such as Open Data and Open Government Data, among other ones. Models, languages, and tools, that allow ...
    • From conceptual to logical ETL design using BPMN and relational algebra 

      Awiti, Judith; Vaisman, Alejandro Ariel; Zimányi, Esteban (2019)
      "Extraction, transformation, and loading (ETL) processes are used to extract data from internal and external sources of an organization, transform these data, and load them into a data warehouse. The Business Process ...
    • Mapping spatiotemporal data to RDF: A SPARQL endpoint for Brussels 

      Vaisman, Alejandro Ariel; Chentout, Kevin (2019)
      "This paper describes how a platform for publishing and querying linked open data for the Brussels Capital region in Belgium is built. Data are provided as relational tables or XML documents and are mapped into the RDF ...
    • Mobility data warehouses 

      Vaisman, Alejandro Ariel; Zimányi, Esteban (2019-04)
      "The interest in mobility data analysis has grown dramatically with the wide availability of devices that track the position of moving objects. Mobility analysis can be applied, for example, to analyze traffic flows. To ...
    • Modelling and querying star and snowflake warehouses using graph databases 

      Vaisman, Alejandro Ariel; Besteiro, María Florencia; Valverde Melito, Maximiliano Javier (2019)
      "In current “Big Data” scenarios, graph databases are increasingly being used. Online Analytical Processing (OLAP) operations can expand the possibilities of graph analysis beyond the traditional graphbased computation. ...
    • Performing OLAP over graph data: query language, implementation, and a case study 

      Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel (2017-08)
      "In current Big Data scenarios, traditional data warehousing and Online Analytical Processing (OLAP) operations on cubes are clearly not sufficient to address the current data analysis requirements. Nevertheless, OLAP ...
    • Piet: a GIS-OLAP implementation 

      Vaisman, Alejandro Ariel; Gómez, Leticia Irene; Kuijpers, Bart; Escribano, Ariel (2007)
      "Data aggregation in Geographic Information Systems (GIS) is a desirable feature, although only marginally present in commercial systems, which also fail to provide integration between GIS and OLAP (On Line Analytical ...
    • RE-SPaM: Using regular expressions for sequential pattern mining in trajectory databases 

      Gómez, Leticia Irene; Vaisman, Alejandro Ariel (2008)
      "In sequential pattern mining, languages based on regular expressions (RE) were proposed to restrict frequent sequences to the ones that satisfy user-specified constraints. In these languages, REs are applied over items. ...
    • Temporal SOLAP: query language, implementation, and a use case 

      Bisceglia, Pablo; Gómez, Leticia Irene; Vaisman, Alejandro Ariel (2012)
      "The integration of Geographic Information Systems (GIS) and On-Line Analytical Processing (OLAP), denoted SOLAP, is aimed at exploring and analyzing spatial data. In real-world SOLAP applications, spatial and non-spatial ...