Cristina Dutra de Aguiar

• Abstract

  Processing OLAP (on-line analytical processing) queries is very expensive because of the huge volume of data stored in the data warehouse and the fact that they perform star-join. Processing SOLAP queries is even more expensive, since spatial data warehouses are more voluminous and perform the star-join extended with costly topological predicates. The processing of OLAP and SOLAP queries …

  Processing of OLAP and SOLAP Queries on Parallel and Distributed Environments, AP.R

• Abstract

  There is a new set of OLAP (on-line analytical processing) queries that can not currently be answered by conventional data warehousing (DWing) applications, since they require the management of both multimedia data, such as images, audio and videos, and geographic data, such as points, lines and polygons. For instance, suppose that a given medical team is interested in determining how man…

  Processing of OLAP queries extended with image similarity predicates and spatial predicates over non-conventional data warehouses, AP.R

• Abstract

  This research project is aimed at improving the query performance of non-conventional databases. In detail, this project focuses on the development of access methods to improve the query performance of geographical data warehouses (GDW) and biological databases (BDB). Access methods (i.e., indices) may reduce the sequential search computational cost, leading the search to portions of the …

  Access methods for improving query performance of non-conventional databases, AP.R

(Only some records are available in English at this moment)

• Abstract

  Aiming to investigate the challenge of building a Big Data Question Answering), the research group conducted by this project supervisor is developing the BigQA software reference architecture. Among its functionalities, BigQA encompasses a module that supports Question Answering algorithms. These algorithms are composed of two steps. The first step, named document retriever, receives ques…

  Investigation of Question Answering Algorithms in the BigQA Software Reference Architecture, BP.IC

• Abstract

  Processing OLAP (on-line analytical processing) queries is very expensive because of the huge volume of data stored in the data warehouse and the fact that they perform star-join. This processing can be benefited by the use of computational environments with large storage and processing capacities, such as clusters of computers and cloud computing. In these environments, it is common the …

  Analytical query processing on parallel and distributed environments, BP.MS

• Abstract

  Spatial database systems are largely used in the management of spatial objects that represent real-world phenomena by using points, lines, and regions. To improve the query processing involving spatial objects, spatial indices are used, such as the R-tree and its variants. These indices consider the magnetic disk as the main storage system. However, non-volatile memories, such as memories…

  Spatial Indexing in Non-Volatile Memories: Proposal of an Efficient and Robust Spatial Index with Durability, BP.DR

(Only some records are available in English at this moment)

• Abstract

  The use of a spatial index is fundamental in spatial database systems because it reduces the search space in the processing of spatial queries, such as intersection range queries. Despite the increasing use of flash-based Solid State Drives (SSDs) in spatial database applications, there is a lack of an efficient flash-aware spatial index that exploits the positive characteristics of SSDs.…

  Porting disk-based spatial indices to flash-based solid state drives, BE.EP.DR

• Abstract

  Models, and their capacity to adapt, are behind any new major technological advance we have seen in the previous decades. From maps in our cellphones to bionic limbs that bring back life quality to an increasing number of people, creating systems with underlying models that can learn and make predictions seem to be a core technique in the foreseeable future. This is directly reflected on…

  A model-based OLAP approach, BE.EP.DR

• Abstract

  The master project conducted by the candidate deals with algorithms to construct and query suffix arrays in external memory. Suffix arrays have been used in different tasks in bioinformatics. Recently Simpson and Durbin (2012) used suffix arrays to assembly genomes efficiently. However, the internal memory requirements impair their usage in large datasets. The objective of the propose…

  Suffix arrays and genome assembly, BE.EP.MS