Fernando Arango

Extending the map cube operator with multiple spatial aggregate functions and map overlay

The map cube operator for spatial multidimensional databases supports spatial aggregation using geometric union and enables information visualization in maps. In this paper, we propose three extensions to the map cube operator. First, support for spatial aggregate functions other than geometric union. Second, support for several spatial aggregate functions simultaneously. Third, support for overlaying the map cube results with maps. In addition, we fix some grammar inconsistencies of this operator. We illustrate our proposed extensions and improvements in a case study about crimes.

Season queries on a temporal multidimensional model for OLAP

Dimensions are usually considered static in a data warehouse. However, because of changing requirements, dimension data and dimension structure can evolve. In this paper we focus on a type of dimension data change called reclassification, i.e., when a member of a level changes its parent in a higher level of a dimension. This kind of change gives rise to the notion of season, i.e., an interval during which two members of a dimension are associated with each other. In this paper we extend a formal temporal multidimensional model with the notion of season and propose query language constructs to enable season queries. A case study about soccer illustrates the application of the proposed extensions, exemplified with several season queries.