A hybrid software process simulation model

This paper deals with simulation modeling of software processes and proposes the combination of three traditional modeling methods (analytical, continuous and discrete-event) into a unique hybrid two-level modeling approach. At the higher abstraction level, the process is modeled by a discreteevent queuing network, which represents the component activities (i.e. service stations), their interactions, and the exchanged artifacts. The implementation details of the introduced activities are given at the lower abstraction level, where the analytical and continuous methods are used. The proposed approach is applied to a waterfall-based software process to study the effects of requirements instability on various process quality attributes, as effort, delivery time, productivity, rework percentage, and product quality. Simulation results show that the use of the model can provide both qualitative and quantitative suggestions on how to change the software process to improve its quality or to achieve specific organizational goals. The model is primarily designed to represent the behaviour of hypothetical projects, to allow researchers to view the implications of their assumptions. However, with small improvements, it can be extended to become a tool for analysing and predicting the behaviour of actual projects. A Hybrid Software Process Simulation Model Paolo Donzelli and Giuseppe Iazeolla 2