Perspectives AAAI Symposium on Agent Mediated Knowledge Management March 26, 2003

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PerspectivesAAAI Symposium on Agent Mediated
Knowledge ManagementMarch 26, 2003

• Sidney Bailin
• Knowledge Evolution, Inc. (www.kevol.com)
• Walt Truszkowski
• NASA/Goddard Space Flight Center

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Problem Scenario

• Agents must cooperate in some task
• They disagree about what must be done

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A Possible Diagnosis and Treatment

• Ontology mismatch
• Agents mean different things by the same terms
• Agents view the world differently
• Solution ontology negotiation
• An incremental process for establishing shared
  understanding
• Cf. Bailin Truszkowski, Ontology negotiation
  between intelligent information agents,
  Knowledge Engineering Review, Volume 17, Issue 1,
  March 2002.

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How do the agents know theres an ontology
mismatch?
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Simple Model of an Observer
Observer
Knowledge Base
Message Stream
Interpretation
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Making Sense of an Observation Iterative KB Update
p, q, r, s, t, u, v, w ...
Message
Update
a, b, c, d, e ?
Interpretation
Update Problem
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Examples of Observation

• Remote Sensing
• Auditory
• Name that tune
• What does this mean?
• Verbal
• Intelligence analysis

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Knowledge Representations

• Propositional
• Assertions
• Ontological
• Assertions about types
• Event sets
• E.g., Probabalistic models
• Attribute sets
• E.g., Neural net interpretations
• Lattice
• States of knowledge

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Propositional Representation
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Event Set Representation
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Attribute Set Representation
Observer
Schema - Type - Source - Capability -
Threat ...
Position 50? Velocity 600 km/hr 70? Size
3m Shape oblong ...
Type Missile Source Adversary Capability
Evasive Threat level High Auto-respond Yes ...
Interpretation
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Attribute Set Representation
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OntologicalRepresentation
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Integrated Model
Events in the initial interpretation process
are the possible attribute-values that can be
inferred about the observed phenomenon.
Ontology
Attributes
Categories
Type Missile Source Adversary Capability
Evasive Threat level High Auto-respond Yes ...
Message
Events in the classification process are the
possible categories to which the observed
phenomenon can be assigned.
Classification
Initial Interpretation
Uncertainty Method
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What is Perspective (1 of 2)

• Something that distinguishes one observation from
  another
• Must be a difference in input, interpretation
  process, or knowledge base

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What is Perspective (2 of 2)

• Choice of input signal
• Signal type
• Wavelength
• State of observer, target of observation, and
  environment
• E.g., time, position, angle of observation
• As represented in the KB
• Interpretation function
• Choice of significant info in input signal
• Mapping of selected signal to KB ontology
• This is like humans perspective on an issue

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When Observations Conflict

• Problem with signal?
• Phenomenon noise
• Resolution method calibration
• Difference in state?
• Phenomenon state-dependent events
• Resolution method correlate state with events
• Difference in interpretation?
• Phenomenon ontology conflict
• Resolution method ontology negotiation

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Summary

• Weve developed a model of observation and
  perspective
• Agents can explicitly represent and reason about
  perspective (theirs and others)
• Agents can use perspective reasoning to determine
  how to resolve a conflict
• In particular, to determine if and when an
  ontology conflict is occurring