Supporting separation of concerns during software architecture performance evaluation

The Systems Engineering Process Activities (SEPA) methodology aims toward enabling concurrent architecture derivation and evaluation as an integral part of the development cycle. The approach involves separating and representing requirements classes using the SEPA 3D Architecture, a formal metamodel consisting of a set of interrelated architecture levels. The SEPA 3D Architecture levels and the requirements classes they capture are (1) the Domain Reference Architecture capturing domain requirements (e.g., business process functionality, data and their relationships, timing between functions), (2) the Application Architecture capturing system-wide non-functional requirements (e.g., application look-and-feel, runtime performance requirements), and (3) the Implementation Architecture capturing installation requirements (e.g., available site hardware platforms, middleware and communications software). This separation of concerns and evolving introduction of requirements from domain-dependent, implementation-independent (e.g. domain requirements) to strictly implementation-related requirements promotes appropriate performance evaluations at appropriate points in the engineering process. These timely and focused evaluations aim to (1) consider performance goals during the derivation of an architecture level, (2) understand the relative performance differences between architectural levels, and (3) appreciate the impact of new information on relative performance between an existing architecture version and an updated architecture version resulting from requirements changes or defect corrections.