A formalism for functionality preserving system level transformations

With the rise in complexity of modern systems, designers are spending a significant time on modeling at the system level of abstraction. This paper introduces Model Algebra, a formalism built on top of system level design languages, that can be used for implementing functionality preserving transformations on system level models. Such transformations enable us to implement high level design decisions without having to write new models for each design decision. Moreover, since these transformations preserve functionality, the transformed models do not need to be reverified. We present the definition of Model Algebra and show how system level models can be represented as expressions in this formalism. The laws of Model Algebra are use to define correct model transformations. We show a system level design scenario, where design decisions gradually refine the functional model of the system to an architectural model with components and communication structure. The refinement can be performed using the correct model transformations in our formalism.