Directionality and stability in system behaviors

A description is given of a formal method for requirement analysis. The method can detect errors in system specifications by exploring formalized alternative views of systems. At the heart of the method is the observation that the roles played by different system constituents are associated with different general behavior patterns, e.g. directionality and stability. Moreover, these intuitions about systems can be formalized so that reasoning tools can be applied. Specifically, the author investigates systems where a stable service is provided. An ideal system model, called a temporally decomposable structurally stable (TDSS) system, is presented in which the intuitions are characterized as formal properties such as conservation of objects, nondeterminism, and logical implication. A program, DAO, embodying these ideas, has been implemented