Requirement Engineering in the Age of System and Product Complexity - A Literature Review

Product, service, and system development can be approached with numerous processes and methodologies. Many of these models begin with the definition of requirements to fulfill. Thus, these requirements outline the purpose of the development and design. Due to the inherent attribute of the requirement definition and the product development process, the aspects to design are usually defined in the beginning, and subsequently implemented or realized. This time difference between the definition and the actual realization of the requirements creates a high potential for uncertainty and risk, which is especially critical when it comes to emergent behaviors and complexity of the product or system. Based on the connection between requirements and complexity, the presented research set out to define and assess the current state of the research in the form of a comprehensive literature review, to serve as a basis for further research. This review includes the topics of general complexity, requirement engineering, and system/product complexity. The literature showed ongoing and active research for both fields with a longer history for complexity. Since it was first mentioned in 1948, complexity has expanded its application and research to various engineering domains which were identified based on cross connections. Requirement engineering showed its origins in computer science/engineering, and successive expansion into other domains, such as mechanical engineering. Both fields, the one for complexity and requirement engineering, also show recent trends, such as the application and inclusion of AI and Machine Learning, Agile, and certain security/resilience foci. All in all, a comprehensive overview for the topics is provided with insights into expansion and evolution.