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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