Requirements Engineering für IT-gestützte Product Service Systems

Nowadays the competitive pressure increases, with the consequence that the differentiation from competitors by goods or services alone is no longer sufficient. For that reason, companies offer integrated bundles of tangible goods and services, which aim to solve a customer’s problem holistically. These bundles are known as Hybrid Products or Product Service Systems (PSS). In case of IT-enabled PSS, the software constitutes an important part of the tangible goods, by realizing the link between the hardware and services elements. Due to their goal of solving a customers’ problem, requirements engineering plays an essential role in the development process of PSS. In literature as well as in practice, a methodology for an integrated requirements engineering for hardware and services, fulfilling the needs of PSS, is still missing. Therefore, the question arises, how requirements engineering for PSS should be designed in order to elicit and manage the requirements on PSS in an integrated way and across all domains. For answering this question, design science is used as a basis. In the first step, the problem is examined in depth by means of literature analyses, empirical studies and case studies in practice. Subsequently, an approach for requirements engineering for IT-enabled PSS is developed, solving the problem determined previously. In the third step of the research, the developed approach is evaluated, using analytical methods and case studies. The requirements engineering approach described in this thesis comprises an artifact model and a procedure model. The artifact model describes the contents of a requirements specification and defines structuring principles for the requirements to PSS. Thus, it supports the interdisciplinary elicitation and concretization of the requirements in accordance with the development process. The procedure model specifies all activities, being performed by requirements engineering in order to elicit and manage the requirements to PSS. Additionally, the procedure model suggests suitable techniques for the realization of each activity. This requirements engineering approach provides concretized requirements that can be implemented by the domains involved in the development of PSS. The analytical evaluation of the requirements engineering approach has shown that all requirements imposed on it are satisfied. By means of case studies, it could be demonstrated that the approach is also suitable in practice and contributes to solving existing challenges. The theoretical contribution of the approach can be seen as a reference model, because the artifact model is a universal model that can be adapted to the needs of individual companies. From the practical point of view, this approach supports the early stages of the development process of PSS. A limitation of the approach is that it mainly refers to IT-enabled PSS including hardware components. Therefore, a topic for further research are PSS, consisting of solely software and service elements. Moreover, the variant management for PSS as well as the traceability of requirements’ implementation are topics for future research. This thesis presents a first integrated approach for requirements engineering for IT-enabled PSS. It realizes the concretization of requirements considering the characteristics of the domains participating in the development of PSS. Thereby, the approach contributes to solving the challenges in practice and improving the understanding of PSS. Inhaltsverzeichnis iii