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Πλοήγηση ανά Θέμα "Spatial database"

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    • Bulk-loading xBR+-trees 

      Roumelis G., Vassilakopoulos M., Corral A., Manolopoulos Y. (2016)
      Spatial indexes are important in spatial databases for efficient execution of queries involving spatial constraints. The xBR+-tree is a balanced disk-resident quadtree-based index structure for point data, which is very ...

    • Distance range queries in spatialhadoop 

      García-García F., Corral A., Iribarne L., Vassilakopoulos M. (2016)
      Efficient processing of Distance Range Queries (DRQs) is of great importance in spatial databases due to the wide area of applications. This type of spatial query is characterized by a distance range over one or two datasets. ...

    • An efficient algorithm for bulk-loading xBR+-trees 

      Roumelis G., Vassilakopoulos M., Corral A., Manolopoulos Y. (2018)
      A major part of the interface to a database is made up of the queries that can be addressed to this database and answered (processed) in an efficient way, contributing to the quality of the developed software. Efficiently ...

    • An efficient flash-aware spatial index for points 

      Carniel A.C., Roumelis G., Ciferri R.R., Vassilakopoulos M., Corral A., Ciferri C.D.deA. (2018)
      Spatial database systems often employ spatial indices to speed up the processing of spatial queries. In addition, modern spatial database applications are interested in exploiting the positive characteristics of flash-based ...

    • Efficient query processing on large spatial databases: A performance study 

      Roumelis G., Vassilakopoulos M., Corral A., Manolopoulos Y. (2017)
      Processing of spatial queries has been studied extensively in the literature. In most cases, it is accomplished by indexing spatial data using spatial access methods. Spatial indexes, such as those based on the Quadtree, ...

    • GIS applications in costal transport: The Co.Tr.I.S case and its contribution towards the islands sustainable smartification 

      Pantazis D.N., Moussas V.C., Stratakis P., Stathakis D., Gkadolou E. (2018)
      Coastal Transport Integrated System (Co.Tr.I.S) is an under development integrated spatial information system for the optimal design of coastal transport lines. This fundamental and applied research project was co-financed ...

    • GPU-Based Algorithms for Processing the k Nearest-Neighbor Query on Disk-Resident Data 

      Velentzas P., Vassilakopoulos M., Corral A. (2021)
      Algorithms for answering the k Nearest-Neighbor (k-NN) query are widely used for queries in spatial databases and for distance classification of a group of query points against a reference dataset to derive the dominating ...

    • 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 ...

    • 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 ...

    • New plane-sweep algorithms for distance-based join queries in spatial databases 

      Roumelis G., Corral A., Vassilakopoulos M., Manolopoulos Y. (2016)
      Efficient and effective processing of the distance-based join query (DJQ) is of great importance in spatial databases due to the wide area of applications that may address such queries (mapping, urban planning, transportation ...

    • Spatial batch-queries processing using xBR+-trees in Solid-State Drives 

      Roumelis G., Vassilakopoulos M., Corral A., Fevgas A., Manolopoulos Y. (2018)
      Efficient query processing in spatial databases is of vital importance for numerous modern applications. In most cases, such processing is accomplished by taking advantage of spatial indexes. The xBR+ -tree is an index for ...

    • The xbr+-tree: An efficient access method for points 

      Roumelis G., Vassilakopoulos M., Loukopoulos T., Corral A., Manolopoulos Y. (2015)
      Spatial indexes, such as those based on Quadtree, are important in spatial databases for efficient execution of queries involving spatial constraints. In this paper, we present improvements of the xBR-tree (a member of the ...