• A-tree: Distributed indexing of multidimensional data for cloud computing environments 

      Papadopoulos, A.; Katsaros, D. (2011)
      Efficient querying of huge volumes of multidimensional data stored in cloud computing systems has become a necessity, due to the widespread of cloud storage facilities. With clouds getting larger and available data growing ...
    • Database design of a geo-environmental information system 

      Roumelis, G.; Loukopoulos, T.; Vassilakopoulos, M. (2014)
      Environmental protection from productive investments becomes a major task for enterprises and constitutes a critical competitiveness factor. The region of Central Greece presents many serious and particular environmental ...
    • Double chain-star: An RDF indexing scheme for fast processing of SPARQL joins 

      Meimaris M., Papastefanatos G. (2016)
      State of the art RDF stores often rely on exhaustive indexing and sequential (self-)joins for SPARQL query processing. However, query execution is dependent on, and often limited by the underlying storage and indexing ...
    • Extended characteristic sets: Graph indexing for SPARQL Query Optimization 

      Meimaris M., Papastefanatos G., Mamoulis N., Anagnostopoulos I. (2017)
      SPARQL query execution in state of the art RDF engines depends on, and is often limited by the underlying storage and indexing schemes. Typically, these systems exhaustively store permutations of the standard three-column ...
    • Indexing in flash storage devices: a survey on challenges, current approaches, and future trends 

      Fevgas A., Akritidis L., Bozanis P., Manolopoulos Y. (2020)
      Indexes are special purpose data structures, designed to facilitate and speed up the access to the contents of a file. Indexing has been actively and extensively investigated in DBMSes equipped with hard disk drives (HDDs). ...
    • Interpolating the air for optimizing wireless data broadcast 

      Tsakiridis, F.; Bozanis, P.; Katsaros, D. (2007)
      Energy conservation and access efficiency are two fundamental though competing goals in broadcast wireless networks. To tackle the energy penalty from sequential searching, the interleaving of index with data items has ...
    • Join-queries between two spatial datasets indexed by a single R*-tree 

      Vassilakopoulos, M.; Corral, A.; Karanikolas, N. N. (2011)
      A spatial join, a common query in Spatial Databases and Geographical Information Systems (GIS), consists in testing every possible pair of data elements belonging to two spatial datasets against a spatial predicate. This ...
    • LB-Grid: An SSD efficient Grid File 

      Fevgas A., Bozanis P. (2019)
      Recent advances in non-volatile memory technology have led to the introduction of solid state drives (SSD). NVMe SSDs are the latest development in flash based solid state drives and they were designed as a means of low ...
    • Merging R-trees 

      Vasaitis, V.; Nanopoulos, A.; Bozanis, P. (2004)
      R-trees, since their introduction in 1984, have been proven to be one of the most well-behaved practical data structures for accommodating dynamic massive sets of geometric objects and conducting a diverse set of queries ...
    • Nearest Neighbor Algorithms using xBR-Trees 

      Roumelis, G.; Vassilakopoulos, M.; Corral, A. (2011)
      One of the common queries in spatial databases is the (K) Nearest Neighbor Query that discovers the (K) closest objects to a query object. Processing of spatial queries, in most cases, is accomplished by indexing spatial ...
    • Porting disk-based spatial index structures to flash-based solid state drives 

      Carniel A.C., Roumelis G., Ciferri R.R., Vassilakopoulos M., Corral A., Aguiar C.D. (2022)
      Indexing data on flash-based Solid State Drives (SSDs) is an important paradigm recently applied in spatial data management. During last years, the design of new spatial access methods for SSDs, named flash-aware spatial ...
    • Predictive join processing between regions and moving objects 

      Corral, A.; Torres, M.; Vassilakopoulos, M.; Manolopoulos, Y. (2008)
      The family of R-trees is suitable for indexing various kinds of multidimensional objects. TPR*-trees are R-tree based structures that have been proposed for indexing a moving object database, e.g. a data-base of moving ...