Requirements Engineering and Systems Architecting are often considered the most important phases of the software development lifecycle. Because of their close proximity in the software development lifecycle, there is a high degree of interaction between these two processes. While such interaction has been recognized and researched in terms of new technology (particularly methods and tools), there is a distinct lack of empirical understanding regarding the scientific properties of this interaction. Furthermore, in Requirements Engineering and Systems Architecting, not only technical but human aspects are considered critical for the success of these processes due to these processes lying at the front-end of the development cycle and therefore being more aligned with real-world issues. Thus, the scientific properties of the interactions between Requirements Engineering and Systems Architecting can be broken down into these two key aspects. For instance, the following example research questions relate to such scientific properties: What is the impact of an existing system’s architecture on requirements decision-making? What kinds of requirements-oriented problems are encountered during architecting? What is the impact of an existing systems architecture on new requirements being elicited? What is the impact of requirements engineering knowledge on systems architecting? There is little in the literature addressing such questions.
This thesis explores such issues through a suite of six exploratory empirical studies that were conducted over the last five years. Based on the observations from these studies, an emerging theory is proposed that describes the impact of human and process factors in the interaction between Requirements Engineering and Systems Architecting. The impact of this emerging body of knowledge is deemed to be on the following: technology development for Requirements Engineering and Software Architecting (methods, tools, processes, etc.); hiring and training personnel for Requirements Engineering and Systems Architecture processes in industry; Requirements Engineering and Systems Architecture project planning; curriculum improvement in academia; and future empirical research in Requirements Engineering and Systems Architecting
