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Uncertainty in Spatial Trajectories

Goce Trajcevski

Chapter outline

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1. Introduction2. Uncertainty Throughout History3. Uncertainty in Spatial and Temporal Database4. Modeling Uncertain Trajectories5. Processing Spatio-Temporal Queries for Uncertain

Trajectories6. Summary

Balance breadth and depth

Uncertainty Throughout History

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1. Philosophy and Logic• Epistemic Logic (BaP)• Modal Logic (,)

• Possible Worlds2. Uncertainty in AI and Databases

• Model-Theoretic issues (Possible Models)• NULLs (open vs. closed world assumption)• Probabilistic databases (and possible worlds)

Time Geography and Inexact Geometries

• Uncertain location over time

• Re-evaluation of Euclidian postulates

Uncertain in Spatial and Temporal Databases

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1. Spatial Databases• Imprecise Locations

• Impact on Queries

2. Temporal Databases• Valid Time• Transaction time

• Constructs (T-SQL)

Modeling Uncertain Trajectories

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Location Uncertainty ModelsVarious Sources’ Imprecision

(GPS; Sensors) Quest for data reduction

Modeling Uncertain Trajectories

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• Cones, Beads, Necklaces

Modeling Uncertain Trajectories

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Sheared Cylinders

Modeling Uncertain Trajectories

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Uncertainty on Road Networks

Processing Spatio-Temporal Queries for Uncertain Trajectories

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• Query Categories• Range• NN

• Few others in “potpourri” • Capturing the impact (of the uncertainty model)

into the syntax of the query

• Discuss a few processing algorithms• “Potpourri”• Other predicates/issues

Processing Spatio-Temporal Queries for Uncertain Trajectories

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Processing Spatio-Temporal Queries for Uncertain Trajectories

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Processing Spatio-Temporal Queries for Uncertain Trajectories

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NN-query for crisp object and uncertain-rest(cone model)

Processing Spatio-Temporal Queries for Uncertain Trajectories

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“Messing” the context

Processing Spatio-Temporal Queries for Uncertain Trajectories

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Potpourri:•Alibi query•Topological Predicates

• Inside-ness;• Along-ness;• Touching;

•Communication savings• V-to-server• WSN