Design of a system starts with functional requirements and expected contexts of use. Early design sketches create a topology of components that a designer expects can satisfy the requirements. The methodology described here enables a designer to test an early design qualitatively against qualitative versions of the requirements and environment. Components can be specified with qualitative relations of the output to inputs, and one can create similar qualitative models of requirements, contexts of use and the environment. No numeric parameter values need to be specified to test a design. Our qualitative approach (QRM) simulates the behavior of the design, producing an envisionment (graph of qualitative states) that represents all qualitatively distinct behaviors of the system in the context of use. In this paper, we show how the envisionment can be used to verify the reachability of required states, to identify implicit requirements that should be made explicit, and to provide guidance for detailed design. Furthermore, we illustrate the utility of qualitative simulation in the context of a topological design space exploration tool.
An FPGA Design Space Exploration Tool for Matrix Inversion Architectures