Requirements hierarchy in the responsive and formal design process

Requirements, stakeholders' visions, drive any systems engineering (SE) process. But in design process practices, there is a gap often present between stakeholders' visions and requirements representation. This limits the impact that the stakeholders can provide input to the SE process. Then, the process may end up with errors or provide a product which is unwanted. We proposed a design methodology called the Responsive and Formal Design (RFD) process that directly involves the stakeholders input at each level of the requirement elicitation, shows its effect on the total system performance, and integrates high level requirements with domain specific considerations and verifies formally. It consists of a set of levels of representaion. Each level represents a set of requirements and its associated models, simulations, and the relationship between them. The levels of representation are related with refinement and abstraction relations. The refinement helps to make clear the connection with parametric considerations. As levels of RFD proceed towards refinement, the design process becomes a local or discipline specific activity, though always with a global perspective. Following our framework, this paper presents the implementation of the refinement process. Each level of the RFD process has its own level of granularity. This is true for the model, logical representation, and simulation of the requirements. In this paper, we define the pair of functions, refinement and abstraction, that exist between two models (system and component models in table form called classifications) and their logical representations (called theories) with different levels of granularity. We also show how high level requirements are interpreted in the refined level. We use an example of data from three small satellites, whose goal is to image the auroral ovals around Earth's magnetic poles, to demonstrate our development.