Distributed defeasible speculative reasoning in ambient environment

Speculative Computation is an effective means for solving problems with incomplete information in an open and distributed environment, such as peer-to-peer environment. It allows such a system to compute tentative (and possibly final) solutions using default knowledge about the current environment, or the agent's perception, even if the communications between peers are delayed or broken. However, previous work in speculative reasoning assumed that agents are hierarchically structured, which may not be the case in reality. We propose a more general multi-agents system with no centralized control. Agents in the framework have equivalent functionalities and can collaborate with each other to achieve their common goals. We characterize the framework using the argumentation semantics of defeasible logic, which provides support of speculative reasoning in the presence of conflicting information. We provide an operational model for the framework and present a prototype implementation of the model.