Handling scenarios complexity in model-based design

Abstract

Given that most large-scale complex engineering systems need to be simplified and layered before being designed, a hierarchical approach is necessary to ensure a global and structured understanding of the whole system, including involved stakeholders, use cases, and associated requirements. Even though use cases in themselves are quite intuitive, the process around them is a much bigger challenge since it usually varies from one situation to another. The key step in the proposed methodology is the identification of the system dimensions as a mean to organize use cases. In this article, we propose a framework to address the system dimensions by defining useful functional spaces and accordingly classify the scenarios. As a case study, we analyze and model a cooperative intersection safety system using a hierarchical method to represent use cases. The key challenge in enhancing intersection safety is to identify vehicles that have a high potential to be involved in a collision as early as possible and take preventive action thereof. Such a system design and implementation needs an analysis phase during which the system to design and its environment are analyzed and decomposed. This approach simplifies the understanding of the intersection crossing problem by applying transformations that reduce its complexity. It begins with a thorough analysis of accidents at intersections and providing the main characteristics of these accidents. From the type and severity of accident scenarios, a classification of relevant scenarios is made. The proposed methodology establishes a strong and intuitive link between use cases on one hand and requirements and functional architecture on the other. Moreover, coherency is increased as the hierarchy of use cases affects the hierarchy in functional architecture.