Date of Award

12-2001

Level of Access

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Spatial Information Science and Engineering

Advisor

Max J. Egenhofer

Second Committee Member

Kathleen Hornsby

Third Committee Member

M. Kate Beard-Tisdale

Abstract

Modeling moving objects involves spatio-temporal reasoning. The continuous movements of objects in space-time captured as discrete samples form geospatial lifelines. Existing lifeline models can represent the movement of objects between samples from most likely location to all possible locations. This thesis builds on a model called lifeline bead and necklace that captures all the possible locations of moving objects. Beads are 3-dimensional representations of an object's movements and a series of beads form a necklace. The extent of finding the possible locations is constrained by the speed of movement of the objects. Intersections of lifelines occur when two or more objects meet in space-time. Lifeline intersections are determined by testing the intersection of lifeline beads and necklaces. This thesis introduces a computational model that calculates the intersection of beads and necklaces. This model reduces the complexity of calculating 3-dimensional intersections to 2-dimensional simple geometric figures. The bead and necklace model is useful to various applications such as tracking of individuals, animals, vehicles, soldiers passing through hazardous spills, or the analysis of criminal activities. Lifeline bead intersections is applicable to interesting situations such as finding out the possibility of two individuals present in a meeting or traveling together, the incidence of an individual with environmental hazards, and determining the spatial and temporal clusters for disease patterns.

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