Perspectives AAAI Symposium on Agent Mediated Knowledge Management March 26, 2003 Sidney Bailin...
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PerspectivesAAAI Symposium on Agent Mediated Knowledge
Management
March 26, 2003
Sidney BailinKnowledge Evolution, Inc. (www.kevol.com)
Walt TruszkowskiNASA/Goddard Space Flight Center
Problem Scenario
• Agents must cooperate in some task
• They disagree about what must be done
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.
How do the agents know there’s an ontology
mismatch?
Observer
InterpretationKnowledge
Base
Message Stream
Simple Model of an Observer
Update Problem
Update a, b, c,d, e ?
Interpretationp, q, r,
s, t,u, v, w
...
Message
Making Sense of an ObservationIterative KB Update
Examples of Observation
• Remote Sensing• Auditory
– Name that tune– “What does this mean?”
• Verbal – Intelligence analysis
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
Observation Type
Propositional Interpretation KB Contents
Auditory · That’s Beethoven’s opus 110
· The tempo is too slow
· The walls of this house are too thin
· My neighbor is a pianist
· My neighbor is an audio buff
· Knowledge of classical music
· Opinions about music performance
· Opinions about house construction
· Beliefs about a person
Remote Sensing · A signature typical of iron
compounds was recognized over this region
· The asteroid surface is marked by
large craters
· The soil contains a high concentration
of olivine
· Spectral analysis
· Topographic knowledge
· Geo-chemical knowledge
Verbal · The Prime Minister speaks in the
capital today
· Tanks are en route to the northern
border
· Preparations for an attack seem to be
underway
· Political events
· Military maneuvers
· Predictions and risk assessment
Propositional Representation
Observation Type
Propositional Interpretation Possible Event Space
Auditory · That’s Beethoven’s opus 110· The tempo is too slow· The walls of this house are too thin· My neighbor is a pianist· My neighbor is an audio buff
· Musical compositions· Features of a musical performance· Architectural features· People’s skills· People’s hobbies
Remote Sensing
· A signature typical of iron compounds was recognized over this region· The asteroid surface is marked by large craters· The soil contains a high concentration of olivine
· Spectral signatures of the elements · Topographic features · Chemical features
Verbal · The Prime Minister speaks in the capital today· Tanks are en route to the northern border· Preparations for an attack seem to be underway
· Political events · Military events · Military events
Event Set Representation
Observer
Interpretation
Schema: - Type - Source - Capability - Threat ...
Position: 50Velocity: 600 km/hr 70Size: 3mShape: oblong...
Type: Missile
Source: Adversary
Capability: Evasive
Threat level: High
Auto-respond: Yes
...
Attribute Set Representation
Observation Type
Observed Attributes Inferred Attributes
Auditory · Instrument: piano· Key: A-flat major· Tempo: slow· Volume: loud
· Possible composer: Beethoven· Possible composition: opus 110· Performance quality: sub- standard· Sound insulation: inadequate
Remote Sensing
· Spectral features· Visual features
· Probable substance: iron· Topographic type: cratered
Verbal · Activity: speech· Actor: Prime Minister· Location: capital
· Goal: rally public· Risk: low
· Activity: movement· Actor: tanks
· Possible goal: launch attack· Risk: high
Attribute Set Representation
Observation
Type
Propositional Interpretation Classification Performed
Auditory · That’s Beethoven’s opus
110
· My neighbor is a pianist
· My neighbor is an audio
buff
· Identification of a specific
entity by its signature
· Classification of an entity
by inference from its
behavior
Remote
Sensing
· A signature typical of iron
compounds was recognized
over this region
· Recognition of the
presence of a type of
substance by its signature
Verbal · Preparations for an attack
seem to be underway
· Identification of a
probable threat on the
basis of associated signs
OntologicalRepresentation
InitialInterpretation
Type: Missile
Source: Adversary
Capability: Evasive
Threat level: High
Auto-respond: Yes
...
Message
AttributesCategories
Classification
Uncertainty Method
Ontology
“Events” in the classification process are the possible categories to which the observed phenomenon can be assigned.
“Events” in the initial interpretation process are the possible attribute-values that can be inferred about the observed phenomenon.
Integrated Model
What is “Perspective” (1 of 2)
• Something that distinguishes one observation from another
• Must be a difference in input, interpretation process, or knowledge base
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 human’s “perspective on an issue:
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
Summary
• We’ve 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