Now showing items 1-20 of 56

  • A cost-based storage format selector for materialized results in big data frameworks 

    Munir, Rana Faisal; Abelló Gamazo, Alberto; Romero Moral, Óscar; Thiele, Maik; Lehner, Wolfgang (2019-05-08)
    Article
    Restricted access - publisher's policy
    Modern big data frameworks (such as Hadoop and Spark) allow multiple users to do large-scale analysis simultaneously, by deploying data-intensive workflows (DIWs). These DIWs of different users share many common tasks (i.e, ...
  • A Data-driven approach to improve the process of data-intensive API creation and evolution 

    Abelló Gamazo, Alberto; Ayala Martínez, Claudia Patricia; Farré Tost, Carles; Gómez Seoane, Cristina; Oriol Hilari, Marc; Romero Moral, Óscar (CEUR-WS.org, 2017)
    Conference report
    Open Access
    The market of data-intensive Application Programming Interfaces (APIs) has recently experienced an exponential growth, but the creation and evolution of such APIs is still done ad-hoc, with little automated support and ...
  • A framework for building OLAP cubes on graphs 

    Ghrab, Amine; Romero Moral, Óscar; Skhiri, Sabri; Vaisman, Alejandro; Zimányi, Esteban (Springer, 2015)
    Conference report
    Open Access
    Graphs are widespread structures providing a powerful abstraction for modeling networked data. Large and complex graphs have emerged in various domains such as social networks, bioinformatics, and chemical data. However, ...
  • A framework for multidimensional design of data warehouses from ontologies 

    Romero Moral, Óscar; Abelló Gamazo, Alberto (2009-07)
    External research report
    Open Access
    Some research efforts have proposed the automation of the data warehouse design in order to free this task of being (completely) performed by an expert and facilitate the whole process. Most advanced approaches exclusively ...
  • A machine learning approach for layout inference in spreadsheets 

    Koci, Elvis; Thiele, Maik; Romero Moral, Óscar; Lehner, Wolfgang (SciTePress, 2016)
    Conference report
    Open Access
    Spreadsheet applications are one of the most used tools for content generation and presentation in industry and the Web. In spite of this success, there does not exist a comprehensive approach to automatically extract and ...
  • Analytical metadata modeling for next generation BI systems 

    Varga, Jovan; Romero Moral, Óscar; Bach Pedersen, Torben; Thomsen, Christian (2018-10)
    Article
    Restricted access - publisher's policy
    Business Intelligence (BI) systems are extensively used as in-house solutions to support decision-making in organizations. Next generation BI 2.0 systems claim for expanding the use of BI solutions to external data sources ...
  • An integration-oriented ontology to govern evolution in big data ecosystems 

    Nadal Francesch, Sergi; Romero Moral, Óscar; Abelló Gamazo, Alberto; Vassiliadis, Panos; Vansummeren, Stijn (CEUR-WS.org, 2017)
    Conference lecture
    Open Access
    Big Data architectures allow to flexibly store and process heterogeneous data, from multiple sources, in its original format. The structure of those data, commonly supplied by means of REST APIs, is continuously evolving, ...
  • An integration-oriented ontology to govern evolution in big data ecosystems 

    Nadal Francesch, Sergi; Romero Moral, Óscar; Abelló Gamazo, Alberto; Vassiliadis, Panos; Vansummeren, Stijn (2019-01)
    Article
    Restricted access - publisher's policy
    Big Data architectures allow to flexibly store and process heterogeneous data, from multiple sources, in their original format. The structure of those data, commonly supplied by means of REST APIs, is continuously evolving. ...
  • A requirement-driven approach to the design and evolution of data warehouses 

    Jovanovic, Petar; Romero Moral, Óscar; Simitsis, Alkis; Abelló Gamazo, Alberto; Mayorova, Daria (2014-08-01)
    Article
    Restricted access - publisher's policy
    Designing data warehouse (DW) systems in highly dynamic enterprise environments is not an easy task. At each moment, the multidimensional (MD) schema needs to satisfy the set of information requirements posed by the business ...
  • A software reference architecture for semantic-aware big data systems 

    Nadal Francesch, Sergi; Herrero Otal, Víctor; Romero Moral, Óscar; Abelló Gamazo, Alberto; Franch Gutiérrez, Javier; Vansummeren, Stijn; Valerio, Danilo (2016-06-13)
    Article
    Open Access
    Context: Big Data systems are a class of software systems that ingest, store, process and serve massive amounts of heterogeneous data, from multiple sources. Despite their undisputed impact in current society, their ...
  • A software tool for e-assessment of relational database skills 

    Abelló Gamazo, Alberto; Burgués Illa, Xavier; Casany Guerrero, María José; Martín Escofet, Carme; Quer, Carme; Rodríguez González, M. Elena; Romero Moral, Óscar; Urpí Tubella, Antoni (Tempus Publications, 2016-01-01)
    Article
    Restricted access - publisher's policy
    The objective of this paper is to present a software tool for the e-assessment of relational database skills. The tool is referred to as LearnSQL (Learning Environment for Automatic Rating of Notions of SQL). LearnSQL is ...
  • ATUN-HL: auto tuning of hybrid layouts using workload and data characteristics 

    Munir, Rana Faisal; Abelló Gamazo, Alberto; Romero Moral, Óscar; Thiele, Maik; Lehner, Wolfgang (2018)
    Conference report
    Restricted access - publisher's policy
    Ad-hoc analysis implies processing data in near real-time. Thus, raw data (i.e., neither normalized nor transformed) is typically dumped into a distributed engine, where it is generally stored into a hybrid layout. Hybrid ...
  • A unified view of data-intensive flows in business intelligence systems : a survey 

    Jovanovic, Petar; Romero Moral, Óscar; Abelló Gamazo, Alberto (2016-12)
    Article
    Open Access
    Data-intensive flows are central processes in today’s business intelligence (BI) systems, deploying different technologies to deliver data, from a multitude of data sources, in user-preferred and analysis-ready formats. ...
  • Automatic multidimensional design of data warehouses from requirements 

    Romero Moral, Óscar; Abelló Gamazo, Alberto (2009-07)
    External research report
    Open Access
    The ideal scenario to derive the multidimensional conceptual schema of a data warehouse would entail a hybrid approach (i.e. a combined data-driven and requirement-driven approach). Thus, the resulting multidimensional ...
  • Automating the multidimensional design of data warehouses 

    Romero Moral, Óscar (Universitat Politècnica de Catalunya, 2010-02-09)
    Doctoral thesis
    Open Access
    Les experiències prèvies en l'àmbit dels magatzems de dades (o data warehouse), mostren que l'esquema multidimensional del data warehouse ha de ser fruit d'un enfocament híbrid; això és, una proposta que consideri tant els ...
  • Big data management challenges in SUPERSEDE 

    Nadal Francesch, Sergi; Abelló Gamazo, Alberto; Romero Moral, Óscar; Varga, Jovan (CEUR-WS.org, 2017)
    Conference report
    Open Access
    The H2020 SUPERSEDE (www.supersede.eu) project aims to support decision-making in the evolution and adaptation of software services and applications by exploiting end-user feedback and runtime data, with the overall goal ...
  • Dimensional enrichment of statistical linked open data 

    Varga, Jovan; Vaisman, Alejandro; Romero Moral, Óscar; Etcheverry, Lorena; Bach Pedersen, Torben; Thomsen, Christian (2016-10-01)
    Article
    Open Access
    On-Line Analytical Processing (OLAP) is a data analysis technique typically used for local and well-prepared data. However, initiatives like Open Data and Open Government bring new and publicly available data on the web ...
  • Discovering functional dependencies from ontologies 

    Romero Moral, Óscar; Calvanese, Diego; Abelló Gamazo, Alberto; Rodríguez Muro, Mariano (Association for Computing Machinery (ACM), 2009)
    Conference report
    Restricted access - publisher's policy
    Nowadays, it is widely accepted that the data warehouse design task should be largely automated. Furthermore, the data warehouse conceptual schema must be structured according to the multidimensional model and as a ...
  • Discovering functional dependencies from ontologies 

    Romero Moral, Óscar; Calvanese, Diego; Abelló Gamazo, Alberto; Rodríguez Muro, Mariano (2009-04)
    External research report
    Open Access
    Discovering functional dependencies is a fundamental step in the design of relational databases and in most system reengineering processes, such as system maintainability and redesign. Typically, this task has been performed ...
  • Discovering meaningful keys from ontologies 

    Romero Moral, Óscar; Abelló Gamazo, Alberto; Montesó, Joan Marc (2009-07)
    External research report
    Open Access
    Object identification is a crucial step in most information systems. Nowadays, we have many different ways to identify entities such as surrogates, keys and object identifiers. However, not all of them guarantee the entity ...