Simulations of distributed systems are powerful, since they allow us to prove the relations among different systems, compare their capabilities and performance and transfer positive and impossibility results from one to another. This thesis aims at analyzing the equivalence of the message passing model and the mobile agent model via a simulation relation. Furthermore, we will examine the simulations that can be obtained between the message passing model and the mobile agent model, when some components of the systems may fail or be under adversarial attack.
We prove the following: a) a simulation of a mobile agent system with black holes by a message passing system with always dead processes, b) a simulation of a message passing algorithm that sends at most k-1 messages to always dead processes by a mobile agent system with black holes and at least k mobile agents, c) a simulation of mobile agent black+ hole system by a message passing system with crash failures and c) a simulation of a mobile agent gray hole system by a message passing system with omission failures. Furthermore we present some positive and impossibility results as a consequence of the simulations presented.