Context sensitivity for networked ontologies

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Context sensitivity for networked ontologies

• Igor Mozetic, Marko Grobelnik, Damjan Bojadijev
• Jozef Stefan Institute
• Slovenia

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text
text
context
explicit
implicit
global
local
Im here
who, where
context-1

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con-text
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con-text
Linguistics relationship to other parts
(sentence, paragraph, )
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con-text
Arts everything else but contents
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con-text
AI modelling of context and use in automated
reasoning, making explicit what is implicit
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Overview

• Formalizing context
• Cyc
• Semantic Web
• C-OWL
• Probabilistic approaches
• JSI related work

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McCarthy 1993

• AI modelling of context and use in automated
  reasoning
• implicit -gt explicit
• ist( context, proposition )
• context collection of assumptions
  (generalization of, partially known)
• nesting, lifting, transcending,

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Cyc Lenat, Guha

• Cyc KB set of microtheories (Mt)
• Microtheory set of axioms
• shared assumptions, topic
• internally consistent
• localized (more efficient) reasoning
• preconditions context in which Mt is applicable

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Cyc (example)

• ist( NaiveStateChangeMt,
• isa( ?X, Freezing )
• outputsCreated( ?X, ?Obj )
• gt
• stateOfMatter( ?Obj, SolidStateMatter ))
• NaiveStateChangeMt domainAssumptions
• forAll ?U
• isa( ?U, StateOfMatterChangeEvent )
• gt
• isa( ?U, CreationOrDestructionEvent )

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Context for Semantic Web Guha et al

• Aggregation from different sources. Issues
• class differences
• property type differences
• point of view
• implicit time
• approximations

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C-OWL Giunchiglia et alContextualizing
ontologies
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OWL Global semantics for multiple (networked?)
ontologies
shared model
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C-OWL Local model semantics
local models
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C-OWL Mappings
context
context
contextualized ontology
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C-OWL ontology is a pair

• OWL ontology (target)
• concepts
• individuals
• roles
• mappings (bridge rules)
• ? equivalence
• ? onto
• ? into
• ? compatible
• ? incompatible

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Probabilistic ontology mappings

• Marko

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JSI related work

• Parametric temporal ontology
• Simultaneous ontologies
• User profiling
• Implicit document context (links)

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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
day(sun)
day(mon)
meets
meets
duration(week) 7duration(day)
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
starts
finishes
day(sun)
day(mon)
meets
meets
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
day(sun)
day(mon)
meets
meets
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
day(sun)
day(mon)
meets
meets
day(now-1)
day(now1)
meets
day(now)
meets
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
day(sun)
day(mon)
meets
meets
equals
day(now-1)
day(now1)
meets
day(now)
meets
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
starts
day(sun)
day(mon)
meets
meets
day(mon)
equals
day(now-1)
day(now1)
meets
day(now)
meets
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
starts
day(sun)
day(mon)
meets
meets
meets
day(mon)
equals
day(now-1)
day(now1)
meets
day(now)
meets
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Temporal ontology

• Temporal algebra Allen
• event temporal interval
• relations before, meets, starts, finishes,

week(now)
week(now1)
meets
starts
finishes
starts
day(sun)
day(mon)
meets
meets
meets
day(mon)
equals
equals
day(now-1)
day(now1)
meets
day(now)
meets
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Parametric temporal ontology

• Parameters
• now
• order of magnitude
• extend
• Determined by context

now ?
day week month year decade
now-1 now now1 now2
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A temporal model Tsunami

Search Rescue
Rebuilding
Earthquake
days
months
minutes
Tsunami
hours
E
T
SR
25.dec 26.dec 27.dec 28.dec 29.dec
30.dec 31.dec 1.jan 2.jan 3.jan
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News analysis
News stream
the same?
yet another one?
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News analysis Temporal model Context
News stream
provides context for subsequent events
model of tsunami
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Summary

• Context ontology, model ?
• global vs. local semantics
• logic vs. probabilistic mappings
• Context point of view ?
• ontology projections
• simultaneous ontologies