Temporal Constraints Between Cyclic Geographic Events

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Temporal Constraints Between Cyclic Geographic
Events
Jorge Campos1,2 and Kathlenn Hornsby2 jorge,khorn
sby_at_spatial.maine.edu
1 Núcleo de Pesquisa em Rede de Computadores
Universidade Salvador (Unifacs) 2 National Center
for Geographic Information and Analysis and
Department of Spatial Information Science and
Engineering University of Maine
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Outline

• Temporal Characteristics of Events
• Temporal Constraints Between Intervals
• A Temporal Model for Cyclic Events
• Cyclic Temporal Constraints

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Events
Events are abstractions that represent phenomena,
activities, and processes of the real world.
Temporal Characteristics of Events
Convex intervals as the temporal construct
representing the time when event is true or is
happening
Evi(Si,Ei)
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Temporal Constraints
Temporal Constraints specify values (or range of
values) to the intervals endpoints
Unary Temporal Constraints
Evi(Si3 , Ei5) Evi(Si2 ? Si3 , Eigt5 ?
Eilt7)
Binary Temporal Constraints
(Evi, Evj, ?)
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Examples of Binary Temporal Constraints
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Events of an Aircrafts Operation
refuel
take-off
tires pressure
taxiing
t
(tires pressure, refuel, centered) (refuel,
taxiing, before) (taxiing, take-off, meets)
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Temporal Representation of Cyclic Events
CycEvi(...,Sin-1, Sin, Sin1...,...,Ein-1,
Ein, Ein1...)
CycEvi(Si,Ei,D)
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Temporal Constraints Between Cyclic Events
University policy whenever possible there is at
least one bus running on the campus
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Temporal Constraints Between Cyclic Events
University policy whenever possible there is at
least one bus running on the campus
New fact A new construction site will close off
some streets in the route of the blue bus
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Temporal Constraints Between Cyclic Events
University policy whenever possible there is at
least one bus running on the campus
New fact A new construction site will close off
some streets in the route of the blue bus
maximize the occurrence of periods of
non-concurrent activities
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A Model of Temporal Relations for Cyclic Events
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A Model of Temporal Relations for Cyclic Events
period of equivalence
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All Possible Characteristic Sets of Correlations
contains, meets, overlappedBy, overlaps, metBy
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Instances of Cyclic Temporal Constraints
Cyclic Constraint - Select one possible
configuration among all possible representative
sets of temporal relations
MaximizeRelation MinimizeRelation
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An Instance of Cyclic Constraint
University policy whenever possible there is at
least one bus running on the campus
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Selecting the Closest Configuration
maximizeDisconnected
contains meets overlappedBy overlaps metBy
startedBy overlaps overlappedBy overlaps
contains overlaps overlappedBy overlaps
finishedBy overlappedBy overlaps overlappedBy
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Selecting the Closest Configuration
maximizeDisconnected
contains meets overlappedBy overlaps metBy
startedBy overlaps overlappedBy overlaps
contains overlaps overlappedBy overlaps
finishedBy overlappedBy overlaps overlappedBy
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A New Temporal Configuration of the Bus
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Selecting the new Closest Configuration
maximizeDisconnected
overlappedBy contains contains meets
overlappedBy contains contains
overlappedBy contains finishedBy
overlappedBy contains, overlaps
contains contains overlaps
contains contains overlaps metBy
startedBy contains overlaps
overlappedBy contains contains overlaps
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Future Work

• Definition of a weight for each temporal relation
  
• Incoporation of some metric information
• Incorporation of more abstract temporal relations
  in our reasoning