Approaches for Integration in System of Systems: A Systematic Review

Software systems have become increasingly complex, and they are often formed by integrating independent systems, resulting in a new class of systems referenced as System of Systems (SoS). The System of Systems Integration (SoSI) emerges as a new challenge and aims to create a new feature by integrating constituent systems that contribute to the overall goal of the SoS. Often the constituent systems tend to be from different sources and behaviors and, as such, tend to employ different terminology and concepts. Also, when SoSI involves the integration of legacy systems, cases where the documentation and the necessary skills for the harmonious integration are readily available are very rare. However, it is observed that there is a lack of studies that are comprehensive and, at the same time, contain a detailed view of how the constituent systems are integrated in order to collectively achieve a common goal. Based on this scenario, the main contribution of this systematic review (SR) is to investigate the state of the art of SoSI and the software engineering methods that assist in the integration between constituent systems of a SoS. The SR has found 1398 studies and, at the end of the selection process, we selected 29 studies for data extraction. Most studies describe individuals and teams who have worked in isolation to develop solutions to certain problems without widespread adoption of a form of integration. Thus, there is a growing concern of researchers in the SoS context. However, it still lacks research and greater dissemination of concepts among researchers in the field.