Validation in Context

In this paper a generic framework inspired by [LX90] is presented for the validation of reactive systems embedded in a test environment, or isolated from their operational environment, thereby inducing a natural classification of validation strategies in different scenarios. We show that verification strategies and falsification strategies are complementary notions (but not necessarily equally strong), and how the choice of strategy for assessing the correctness of systems in different scenarios affects the outcome of the validation process. The significance of this paper lies in the provision of systematic principles to perform validation in context, and it gives a theoretical explanation of validation strategies that have already been applied informally in practice. The theory in this paper provides a guide for performing correctness assessment of systems in context, and shows that the correctness of systems in such cases can be approximated in the sense that the risk of considering an incorrect system correct can be reduced systematically.