Modeling the Impact of Requirements Change in the Design of Complex Systems

Abstract

Managing changes in requirements more effectively than others can become a source of competitive advantage for companies designing and developing complex systems. In this paper, we report that decision-makers in these firms feel that understanding the effects of requirements change in the design process is a difficult task in practice. Such knowledge is however crucial to organize the design process in ways that mitigate for the impact of requirement change. Considering this need, we propose here a modeling framework to determine the impact of requirements change in the design process of complex systems. We view the design process as a requirements-driven process containing steps performed in a mechanical way, but ultimately controlled and steered by the human agents involved in it. Therefore, we develop a technique which allows the modeler to capture both the mechanical relationships and the decision-making behavior of design agents. We introduce attributes such as requirements availability, stability, difficulty and margin, which act as process variables driving the design process. Task properties and the agents’ behavior are then modeled as functions of these process variables, which are dynamically updated as the design process progresses and decisions are taken. The potential of this modeling technique is illustrated on the design process of a turbine blade cooling system. Discrete-event Monte Carlo simulations are used to assess the impact of requirements change during design.