Trajectory databases: data models, uncertainty and complete query languages

Abstract

Moving ob jects produce tra jectories. We describe a data model for tra jectories and tra jectory samples and an efficient way of mod- eling uncertainty via beads for tra jectory samples. We study transfor- mations for which important physical properties of tra jectories, such as speed, are invariant. We also determine which transformations preserve beads. We give conceptually easy first-order complete query languages and computationally complete query languages for tra jectory databases, which allow to talk directly about speed and beads. The queries express- ible in these languages are invariant under speed- and bead-preserving transformations.