Modelado de relaciones espacio-temporales en aplicaciones orientadas por objetos

Abstract

In this paper, we extend a data model to support temporal objects and relationships by including new classes named TemporalObject, TemporalRepresentation, and TemporalGraph. The temporal extension to the model is based on the mixed model, which consider a linear, totally ordered and discrete time line, where intervals are its primitives We define a spatio-temporal object as an object that has at least one spatial and one temporal property. These properties are represented by spatial and temporal data, respectively. It can be represented by a four-tuple (objId, geom, t, att) where objId is the object identifier, geom is the geometry that indicates the spatial location and shape of that object, t is the description of the temporal characteristics of that object, and att is a set of other attributes that describes the object. We consider three groups of relationships, namely: spatio-temporal, spatial, and temporal. In the spatio-temporal, we only consider the topological relationships among d-dimensional rectangles, called here hyper-rectangles, where spatial and temporal dimensions are treated homogeneously. An object instance of the spatio-temporal object (STObject) inherits spatial and temporal representation, but internally it is stored in a uniform manner by applying transformation functions to it. Thus, a STObject has a unique representation, which unifies its representation. Our model provides support for representing networks through the notion of spatio-temporal graphs. A spatio-temporal graph is a graph composed of nodes which are spatio-temporal objects and arcs (edges) that are spatio-temporal relationships other than topological ones.