The FAS Method

Summary

The functional architecture is often mentioned in publications about systems engineering or in the context of real system projects. This chapter describes Functional Architectures for Systems (FAS) and begins with the terminology and motivation of functional architectures. The FAS method is a practice‐proven method based on common model‐based systems engineering practices. The functional architecture is based on functional elements, functional interfaces, and architecture decisions. The chapter sheds light on different aspects of functional architectures like tool support, nonfunctional requirements, functional architectures for cyber‐physical systems, and the role of technology in a technology‐independent description. It provides heuristics to create groups of use case activities. While the FAS method is independent of any language or tool, the chapter shows its application using SysML because this language is well suited for implementing it. SysML provides a allocate relationship to model allocations from functional to physical blocks. Functional architectures are on different levels according to the SYSMOD zigzag pattern.