DEVS-based Software Process Simulation Modeling : Formally Specified , Modularized , and Extensible SPSM ∗

This paper proposes DEVS (Discrete Event System Specification)-based software process simulation modeling method which is a formally specified, modularized, and extensible simulation modeling approach. The proposed approach adopts DEVS formalism, a general purpose discrete event modeling and simulation framework, to the software process simulation modeling domain. This approach enables us to clearly understand the software process simulation model by formal specification, and provides explici t extension point to extend the simulation model for a specific purpose. This approach also provides naturally hybrid software process simulation modeling environment, which embeds DESS (Differential Equation System Specification) and DTSS (Discrete Time System Specification) into DEVS formalism. This hybrid approach overcomes some limitations of system dynamics simulation models, such as difficulties of controlling process execution, representing explicit process activity, and modeling inhe rent uncertainty.