Research Activity Overview

• On the theoretical side, it was concentrated on the development of Methodologies for Solving Conflicting Beliefs in multiagent systems with reason maintenance. The conflicts addressed are of two types:
• Belief/Disbelief Conflicts, which occur when the agents are confronted with opposite belief status regarding shared propositions;
• Disbelief Conflicts which occur when incompatible sets of beliefs are detected and, as a result, previously held conclusions have to be abandoned (reason maintenance).
The proposed scenario, unlike in typical multiagent systems, where the resolution of a conflict resolution is performed once and for all, regards conflict solving as a non-monotonic activity where the same conflict may have to be solve more than once. The non-monotonic conflict is a conflict of beliefs regarding a shared information that evolves whenever any alteration regarding the set of beliefs or the number of agents involved in the conflict is detected. These events are called conflict episodes, and, every time a new conflict episode is identified the conflict has to be re-evaluated and solved again.
Two methodologies were designed for the resolution of the identified types of negative conflicts:
• A methodology for solving Belief/Disbelief conflicts - a selection process based on the assessment of the credibility values of the opposing belief status, and
• A methodology for solving Disbelief conflicts - a search process for an unique consensual alternative based on a "next best candidate" strategy.
The conflict solving methodologies conceived make extensive use of the reason maintenance capabilities since the outcome of non-monotonic conflicts are revisable.
Although the conflicts addressed may be considered specific of the investigated framework, the methodologies developed are general and can be applied to more general kinds of conflicts. On one hand, the Belief/Disbelief conflicts represent the negative type of conflicts where a fundamented choice between two opposite results has to be made, while on the other hand, the Disbelief conflict is a negative type of conflict (resulted from the detection of a set of invalid beliefs) where the solution lays on the search for an alternative consensus. The search for a consensus is a well suited methodology for the general type of negative conflicts, especially when more than two irreconcilable perspectives are in conflict - the involved agents try to find alternative support for believing in an unique perspective.
• On the practical side, it was focussed on the actual implementation of the conceived conflict solving methodologies on the Distributed Belief Revision Test bed and on the Project Location Application.