Presentaciones a Congresos
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Browsing Presentaciones a Congresos by Subject "BASES DE DATOS"
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ponencia en congreso.listelement.badge Aggregation languages for moving object and places of interest(2008) Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel"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, we study the compression of trajectory data, produced by moving objects, using the notions of stops and moves. We show that stops and moves are expressible in our query language and we consider a fragment of this language, consisting of regular expressions to talk about temporally ordered sequences of stops and moves. This fragment can be used not only for querying, but also for expressing data mining and pattern matching tasks over trajectory data."ponencia en congreso.listelement.badge Performing OLAP over graph data: query language, implementation, and a case study(2017-08) Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel"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 operations and models can expand the possibilities of graph analysis beyond the traditional graph-based computation. In spite of this, there is not much work on the problem of taking OLAP analysis to the graph data model. In previous work we proposed a multidimensional (MD) data model for graph analysis, that considers not only the basic graph data, but background information in the form of dimension hierarchies as well. The graphs in our model are node- and edge-labelled directed multi-hypergraphs, called graphoids, defined at several different levels of granularity. In this paper we show how we implemented this proposal over the widely used Neo4J graph database, discuss implementation issues, and present a detailed case study to show how OLAP operations can be used on graphs."ponencia en congreso.listelement.badge Trajectory sequential patterns with regular expression constraints including spatial queries(2010-05) Gardella, Pablo; Gómez, Leticia Irene; Vaisman, Alejandro Ariel"Moving object (MO) data representation and computing have received a fair share of attention over recent years from the database community. Replacing raw trajectory data (i.e., MO positions at different time instants) by sequences of application-dependent stops occurred at so-called places of interest (Pols) leads to the notion of semantic trajectories. Different techniques exist for sequential pattern analysis of trajectories defined in this way. One of them, RE-SPaM, expresses sequential patterns by means of regular expressions built not only over item identifiers, but also over constraints defined on the (temporal and non-temporal) attributes of the items to be analyzed. This analysis could be greatly enriched if spatial and non-spatial data associated with the MO are taken into account. In this paper we show how we can take advantage of the extensibility properties of RE-SPaM to augment its expressive power by allowing to include spatial queries in the constraints. For this, we make use of Piet, a framework allowing to integrate OLAP, GIS and MO data, and its associated query language denoted Piet-QL, providing a link between moving object data and their geographic environment."