Active Interaction Complexity  in Systems Engineering

Abstract: The master's thesis describes how complexity measurement can enhance product development or design processes in collaboration with Scania CV AB. Scania has a strong track record in vehicle modularization and thus wanted to investigate the possibility of using complexity measures when architecting, developing, and maintaining complex engineering products such as electrified or self-driving trucks and buses to gain various types of benefits. The section YMPI at Scania, where the project is conducted, had, however, little experience in complexity measurements wants to identify and investigate which complexity measure effectively captures the complexity of a complex system. A fairly complicated industrial case of a conceptual Battery Electric Vehicle (BEV) variant was utilized to demonstrate the newly proposed complexity metric methodology and demonstrate its ability to determine the technical complexity of a system. As a result, the thesis author found a specific case study at Scania and used appropriate methodologies to determine the complexity of the chosen subsystem using the newly proposed complexity measure. This was done by adapting the DSM (Design Structure Matrix) before clustering it with the IGTA++ clustering algorithm. The proposed complexity metric yields a higher complexity number when compared to the traditional product complexity metric.  Another purpose of the thesis was to answer the research questions and conduct a literature review in the field of Model Based System Engineering and product architecting to define the state-of-the-art. The thesis concludes that the newly proposed complexity metric, when implemented on the chosen subsystem, yields a higher complexity number when compared to the number obtained from product complexity, implying that including the directions of an interaction between the components and taking into account the active interacting components improves the accuracy of the complexity measure.  Therefore, it is recommended to Scania to use this proposed method to find the complexity of the system and to compare how the system gets complex when incorporating new technologies or modifying the system or product architecture, as well as to utilize this as a safety and a performance factor for a system.