Virtual environment modeling for requirements validation of high consequence systems

An essential type of "evidence" of the correctness of the requirements formalization process can be provided by human-based calculation. Human calculation can be significantly amplified by shifting from symbolic representations to graphical representations. Having a formally-defined system model, we can visualize formulas that represent the functional behavior of the system and associated safety constraints. This, in turn, provides an environment for the validation of system models. The visual model strengthens the specifier's ability to grasp the system's complexity, build a correct mental model of the system and write the symbolic specification. The visual model can also serve as a bridge between the domain expert and symbolic specification, and provide evidence of the correctness of the formalization process. As a case study, we developed a virtual environment model for the Production Cell robotic system. The model runs in the ImmersaDesk virtual reality environment. We used this model to evaluate the applicability of virtual reality environments for software requirements validation. Although it introduces higher cost in the requirements formalization phase, this approach can be very beneficial in the development of high-consequence systems.