(A) framework of modeling and simulation for mobile agent systems

Abstract

A mobile agent technology is an emerging technology that enables the autonomous, asynchronous execution of a mobile program navigating hosts in a heterogeneous, partially disconnected network. Mobile agent technology has a wide application area such as electronic commerce, distributed information retrieval and network management. Many researchers in this area rely upon simulation to solve their challenging research problems, but the simulation has been done from scratch in most cases due to lack of formal methods. This paper presents the formal modeling and simulation framework for mobile agent systems as well as conventional discrete event systems. A Mobile Discrete Event System Specification(MDEVS) formalism, an extension of Discrete Event System Specification (DEVS) formalism, is able to represent the dynamics of mobile agent systems. The MDEVS formalism provides the formal method of modeling mobile agent systems by supporting the structural changes of the systems which includes the creation, addition, deletion, and migration of models and the dynamic change of couplings between models. We also proposes the abstract simulation algorithm for the MDEVS formalism. AgentSim is a simulator for mobile agent systems modeled by MDEVS formalism. AgentSim is implemented using an actual agent development toolkit - IBM``s Aglets Software Development Kits. Every model becomes an actual mobile agent during simulation and the mobile nature of the agents makes it possible to perform distributed simulation. Also, we can easily obtain the target mobile agent system by just replacing virtual simulation time to real time. Finally, we take a sample electronic commerce system as an example of the modeling and simulation of mobile agent systems with the AgentSim simulation environment.