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El autor Jose R. Parama ha publicado 4 artículo(s):

1 - Compact and queryable representation of raster datasets

Titulo: Compact and queryable representation of raster datasets Autores: Susana Ladra, José R. Paramá, Fernando Silva-Coira Congreso: INTERNATIONAL CONFERENCE ON SCIENTIFIC AND STATISTICAL DATA BASE MANAGEMENT (SSDBM) 2016 Clasificación Ranking SCIE. Clase 2 (A-) Clasidicación CORE: A Citas: 2 DOI: http://dx.doi.org/10.1145/2949689.2949710

Autores: Susana Ladra / José R. Paramá / Fernando Silva-Coira / 
Palabras Clave: Compresión de datos - Ráster - Sistemas de Informacíon Geográfica

2 - Scalable and queryable compressed storage structure for raster data

Titulo: Scalable and queryable compressed storage structure for raster data Autores: Susana Ladra, José R. Paramá, Fernando Silva-Coira Revista: Information Systems Volume 72, December 2017, Pages 179-204Factor de impacto: 2.777Ranking JCR: Q2Citas: 1 DOI: https://doi.org/10.1016/j.is.2017.10.007

Autores: Susana Ladra / Jose R. Parama / Fernando Silva-Coira / 
Palabras Clave: Compresión de datos - Ráster - Sistemas de Informacíon Geográfica

3 - The largest empty circle in Spatial Databases

Given a set S of points in the two-dimensional space, which are stored in a spatial database, this work presents an efficient algorithm to find the empty circle, in the area delimited by those points, with thelargest area and containing only a query point q.Our algorithm adapts previous work in the field of computational geometry to be used in spatial databases, which require to manage large amounts of data. To achieve this objective, the basic idea is to discard a large part of the points of $S$, in such a way that the problem can be solved providing only the remaining points to a classical computational geometry algorithm that, by processing a smaller collection of points, saves main memory resources and computation time.The correctness of our algorithm is formally proven. In addition, we empirically show its efficiency and scalability by running a set of experiments using both synthetic and real data.

Autores: Gilberto Gutiérrez / Juan R. López / José R. Paramá / Miguel R. Penabad / 
Palabras Clave: geographical information systems - largest empty circle - query processing - Spatial databases

4 - An index for moving objects with constant-time access to their compressed trajectories

As the number of vehicles and devices equipped with GPS technology has grown explosively, an urgent need has arisen for time- and space-efficient data structures to represent their trajectories. The most commonly desired queries are the following: queries about an object’s trajectory, range queries and nearest neighbor queries. In this paper we consider that the objects can move freely and we present a new compressed data structure for storing their trajectories, based on a combination of logs and snapshots, with the logs storing sequences of the objects’ relative movements and the snapshots storing their absolute positions sampled at regular time intervals. We call our data structure ContaCT because it provides Constant-time access to Compressed Trajectories. Its logs are based on a compact partial-sums data structure that returns cumulative displacement in constant time, and allows us to compute in constant time any object’s position at any instant, enabling a speedup when processing several other queries. We have compared ContaCT experimentally with another compact data structure for trajectories, called GraCT, and witha classic spatio-temporal index, the MVR-tree. Our results show that ContaCT outperforms the MVR-tree by orders of magnitude in space and also outperforms the compressed representation in time performance.

Autores: Nieves R. Brisaboa / Travis Gagie / Adrián Gómez-Brandón / Gonzalo Navarro / Jose R. Parama / 
Palabras Clave: Compact data structures - Spatio-temporal query - Trajectories representation