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Rumours and Reputation: Evaluating Multi-Dimensional Trust within a Decentralised Reputation System

Rumours and Reputation: Evaluating Multi-Dimensional Trust within a Decentralised Reputation System
Rumours and Reputation: Evaluating Multi-Dimensional Trust within a Decentralised Reputation System
In this paper we develop a novel probabilistic model of computational trust that explicitly deals with correlated multi-dimensional contracts. Our starting point is to consider an agent attempting to estimate the utility of a contract, and we show that this leads to a model of computational trust whereby an agent must determine a vector of estimates that represent the probability that any dimension of the contract will be successfully fulfilled, and a covariance matrix that describes the uncertainty and correlations in these probabilities. We present a formalism based on the Dirichlet distribution that allows an agent to calculate these probabilities and correlations from their direct experience of contract outcomes, and we show that this leads to superior estimates compared to an alternative approach using multiple independent beta distributions. We then show how agents may use the sufficient statistics of this Dirichlet distribution to communicate and fuse reputation within a decentralised reputation system. Finally, we present a novel solution to the problem of rumour propagation within such systems. This solution uses the notion of private and shared information, and provides estimates consistent with a centralised reputation system, whilst maintaining the anonymity of the agents, and avoiding bias and overconfidence.
1063-1070
Reece, Steven
b79cac5b-bbd2-4038-b47d-3d4c845802aa
Rogers, Alex
f9130bc6-da32-474e-9fab-6c6cb8077fdc
Roberts, Stephen
fef5d01c-92bd-44cf-93f0-923ec24f8875
Jennings, N. R.
ab3d94cc-247c-4545-9d1e-65873d6cdb30
Reece, Steven
b79cac5b-bbd2-4038-b47d-3d4c845802aa
Rogers, Alex
f9130bc6-da32-474e-9fab-6c6cb8077fdc
Roberts, Stephen
fef5d01c-92bd-44cf-93f0-923ec24f8875
Jennings, N. R.
ab3d94cc-247c-4545-9d1e-65873d6cdb30

Reece, Steven, Rogers, Alex, Roberts, Stephen and Jennings, N. R. (2007) Rumours and Reputation: Evaluating Multi-Dimensional Trust within a Decentralised Reputation System. Sixth International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS-07), United States. 14 - 18 May 2007. pp. 1063-1070 .

Record type: Conference or Workshop Item (Paper)

Abstract

In this paper we develop a novel probabilistic model of computational trust that explicitly deals with correlated multi-dimensional contracts. Our starting point is to consider an agent attempting to estimate the utility of a contract, and we show that this leads to a model of computational trust whereby an agent must determine a vector of estimates that represent the probability that any dimension of the contract will be successfully fulfilled, and a covariance matrix that describes the uncertainty and correlations in these probabilities. We present a formalism based on the Dirichlet distribution that allows an agent to calculate these probabilities and correlations from their direct experience of contract outcomes, and we show that this leads to superior estimates compared to an alternative approach using multiple independent beta distributions. We then show how agents may use the sufficient statistics of this Dirichlet distribution to communicate and fuse reputation within a decentralised reputation system. Finally, we present a novel solution to the problem of rumour propagation within such systems. This solution uses the notion of private and shared information, and provides estimates consistent with a centralised reputation system, whilst maintaining the anonymity of the agents, and avoiding bias and overconfidence.

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More information

Published date: 2007
Additional Information: Event Dates: May 2007
Venue - Dates: Sixth International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS-07), United States, 2007-05-14 - 2007-05-18
Organisations: Agents, Interactions & Complexity

Identifiers

Local EPrints ID: 263260
URI: https://eprints.soton.ac.uk/id/eprint/263260
PURE UUID: e3511389-5cd6-4b0c-922a-b4ed7a6becb0

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Date deposited: 20 Dec 2006
Last modified: 16 Jul 2019 22:42

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