Trust in Decentralized MAS Openness Management
G. M ULLER and L. V ERCOUTER and O. B OISSIER muller, vercouter, boissier @emse.fr. Ecole Nationale Superieure des Mines Saint-Etienne SIMMO - SMA France
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Outline
Context; Brief State of the Art; Definitions; General framework for trust management; Conclusion;
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Outline
Context
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Context Distributed Openness Management [Vercouter 2000]: A2
x : {A1 , A2 }
A3
A1
x : {A1 , A2 }
Trust in Decentralized MAS Openness Management – p.4/18
Context Distributed Openness Management [Vercouter 2000]: A2
x : {A1 , A2 }
A3
A1 x? x : {A1 , A2 }
x?
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Context Distributed Openness Management [Vercouter 2000]: A2
x : {A1 , A2 }
A3
A1 x : {A1 } x : {A1 , A2 }
x : {A1 }
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Context Trust in Distributed Openness Management: A2
x : {A1 , A2 }
???? Trust? Distrust? A3
A1 x : {A1 } x : {A1 , A2 }
x : {A1 }
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Outline
State of the art
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State of the Art - Common Points Personal attribute based on . . . ; . . . Observation of a “characteristic” of someone (something);
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State of the Art - Common Points Personal attribute based on . . . ; . . . Observation of a “characteristic” of someone (something); Belief (leveled); Time-dependant concept;
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State of the Art - Common Points Personal attribute based on . . . ; . . . Observation of a “characteristic” of someone (something); Belief (leveled); Time-dependant concept; Multi-dimensional concept (M C K NIGHT); Social aspect (C ONTE).
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M C K NIGHT’s (al.) Model Dispositional
Institutional
Trust in general others
Trust in situations/structures
Inter−personal Trust in specific others
Disposition Trusting Beliefs
to trust
Institution based trust
Trusting intention
Trust related Behavior
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C ONTE’s (al.) Model E: non-empty set of agents who share the evaluation; T: non-empty set of evaluation targets; B: non-empty set of beneficiaries; M: non-empty set of agents who share the meta-belief that e’s ( E) share the evaluation; The “Gossip” process.
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Target
Evaluator
C ONTE’s (al.) Model Observed interactions
X
Y
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Target
Evaluator
Beneficiary
C ONTE’s (al.) Model Observed interactions
Beneficiary
Request
X
Y
Trust in Decentralized MAS Openness Management – p.9/18
Target
Evaluator
Gossip
Beneficiary
C ONTE’s (al.) Model Observed interactions
Beneficiary
Trust
value
X
Y
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Outline
Definitions
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Definitions We focus on interpersonal trust Beneficiary’s belief about the Target for ; Trust is a social relation Observers, Evaluators, Gossipers;
Trust as a leveled attribute “ ” ; Trust is a multi-dimensional concept 4 types are used;
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Definitions Agents that knows each others A1
A3 Already integrated agents x : {A1 , A2 }
A2
x : {A1 }
A4
x : {A1 , A2 }
x : {A1 , A2 }
Trust in Decentralized MAS Openness Management – p.12/18
Definitions
A1
A3
x : {A1 , A2 }
x : {A1 }
3
x : {A1 }
2 x?
A2
1 x : {A1 }
0
A4
x : {A1 , A2 }
x : {A1 , A2 } D detects C’s cheat
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Definitions - Trust T : Target B: Beneficiary E : Evaluator O : Observer G : Gossiper
Roles : T A1
A3
x : {A1 , A2 }
x : {A1 }
x : {A1 }
Roles : B, O, E A2
A4
x : {A1 , A2 }
x : {A1 , A2 }
Trust(A 4 ,A 1 ,α )
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Definitions - Witness-Reputation Roles : T Roles : T
T : Target B: Beneficiary E : Evaluator O : Observer G : Gossiper
Roles : B, E
A1
A3
x : {A1 , A2 }
x : {A1 }
Roles : O, G Roles : B, O, E A2
Witness−Reputation(A 3 , A 1 , α
Observation: cheat
A4
x : {A1 , A2 }
x : {A1 , A2 }
Trust(A 4 ,A 1 ,α )
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Definitions - Neighbor-Reputation Roles : T Roles : T Roles : T
T : Target B: Beneficiary E : Evaluator O : Observer G : Gossiper
Roles : B, E
A1
A3
x : {A1 , A2 }
x : {A1 }
Witness−Reputation(A 3 , A 1 , α
Roles : O, G, E Roles : O, G Roles : B, O, E
Roles : B A2
A4
x : {A1 , A2 }
x : {A1 , A2 }
Trust(A 4 ,A 1 ,α )
Evaluation
Neighbor−Reputation( A 2 , A 1 , α )
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Outline
General Framework
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General Framework Information
Update Process
Decision Process Trust
Witness Reputation
Observation Evaluation
Neighbor Reputation
Confidence
Trust Intention
Distrust Intention
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General Framework Information
Neighbor−Reputation Witness−Reputation
Decision Process Trust
< threshold
Trust
1
≥ threshold
1
≥ threshold
2
≥ threshold
3
Mental State
Unknown or not reliable
Witness Reputation < threshold
Witness Reputation
2
Unknown or not reliable
Confidence
< threshold
Neighbor Reputation
3
Neighbor Reputation
Unknown or not reliable
< threshold DI
Trust
Individual Reputation
Observation Evaluation
Trust Related Concepts
Collective Reputation
Update Process
≥ threshold 4
Confidence
4
TI
Confidence
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General Framework Reasoning Process: ≥ threshold 1
≥ threshold 2
≥ threshold 3 Trust intention
≥ threshold
Trust (Mental State)
Witness Reputation
Neighbor Reputation
Confidence
< threshold
< threshold 1
< threshold 2
< threshold 3
4
4
Distrust intention
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General Framework Reasoning Process: ≥ threshold 1
≥ threshold 2
≥ threshold 3 Trust intention
≥ threshold
A 1 : x: { A1 }
Trust (Mental State)
Witness Reputation
Neighbor Reputation
Confidence
< threshold
< threshold 1
< threshold 2
< threshold 3
4
4
Distrust intention
A3
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General Framework Reasoning Process: ≥ threshold 2
≥ threshold 1
≥ threshold 3 Trust intention
≥ threshold
A 1 : x: { A1 }
Trust (Mental State)
Unknown or not reliable
Witness Reputation
Unknown or not reliable
Neighbor Reputation
Unknown or not reliable
Confidence
< threshold
< threshold 1
< threshold 2
< threshold 3
4
4
Distrust intention
A3
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General Framework Update Process:
Trust Related Concepts
G= ∅
G ⊂Ω
Individual Reputation G∩ E = ∅
O=B
Trust
Collective Reputation
Confidence
G∩ E ≠ ∅
Witness−Reputation
Neighbor−Reputation
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General Framework Update Process:
B = beneficiary : Observation
Trust Related Concepts
G= ∅
G ⊂Ω
Individual Reputation G∩ E = ∅
O=B
Trust
Collective Reputation
Confidence
G∩ E ≠ ∅
Witness−Reputation
Neighbor−Reputation
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General Framework Update Process:
Trust Related Concepts
C≠ B : Observation
G= ∅
G ⊂Ω
Individual Reputation G∩ E = ∅
O=B
Trust
Collective Reputation
Confidence
G∩ E ≠ ∅
Witness−Reputation
Neighbor−Reputation
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General Framework Update Process:
C≠ B : Evaluation Trust Related Concepts
G= ∅
G ⊂Ω
Individual Reputation G∩ E = ∅
O=B
Trust
Collective Reputation
Confidence
G∩ E ≠ ∅
Witness−Reputation
Neighbor−Reputation
Trust in Decentralized MAS Openness Management – p.14/18
General Framework Update Process:
default rule
Trust Related Concepts
G= ∅
G ⊂Ω
Individual Reputation G∩ E = ∅
O=B
Trust
Collective Reputation
Confidence
G∩ E ≠ ∅
Witness−Reputation
Neighbor−Reputation
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Outline
Conclusion, Future Work
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Conclusion General framework for trust in Decentralized Openness Management; Representation of 4 kinds of trust: Trust, Witness-Reputation, Neighbor-Reputation, Confidence;
Reasoning on trust: use of the “unknown” state;
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Future Work
Express the framework in a MAS Organisational Model; Develop the Openness Management Solution.
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Questions
Please send your questions to:
[email protected]
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