A Survey on the Interplay between Software Engineering and Systems Engineering during SoS Architecting

Abstract

Background: The Systems Engineering and Software Engineering disciplines are highly intertwined in most modern Systems of Systems (SoS), and particularly so in industries such as defense, transportation, energy and health care. However, the combination of these disciplines during the architecting of SoS seems to be especially challenging; the literature suggests that major integration and operational issues are often linked to ambiguities and gaps between system-level and software-level architectures. Aims: The objective of this paper is to empirically investigate: 1) the state of practice on the interplay between these two disciplines in the architecting process of systems with SoS characteristics; 2) the problems perceived due to this interplay during said architecting process; and 3) the problems arising due to the particular characteristics of SoS systems. Method: We conducted a questionnaire-based online survey among practitioners from industries in the aforementioned domains, having a background on Systems Engineering, Software Engineering or both, and experience in the architecting of systems with SoS characteristics. The survey combined multiple-choice and openended questions, and the data collected from the 60 respondents were analyzed using quantitative and qualitative methods. Results: We found that although in most cases the software architecting process is governed by system-level requirements, the way requirements were specified by systems engineers, and the lack of domain-knowledge of software engineers, often lead to misinterpretations at software level. Furthermore, we found that unclear and/or incomplete specifications could be a common cause of technical debt in SoS projects, which is caused, in part, by insufficient interface definitions. It also appears that while the SoS concept has been adopted by some practitioners in the field, the same is not true

System- and Software-level Architecting Harmonization Practices for Systems-of-Systems : An exploratory case study on a long-running large-scale scientific instrument

“…A previous study by Cadavid et al [10] already found that mutual assumptions at system-and software-level are a major issue during SoS architecting. In this study, we confirmed this insight, discovering that, in large scale systems, assumptions on the dynamic behavioral aspects of software-intensive subsystems such as the ones related to time are, indirectly, a major cause of budget, integration and operation-related problems.…”

“…Overall, the negative impact of insufficient emphasis on the dynamic (behavioral) elements of the sub-systems, and the communication challenges in multidisciplinary engineering teams (cf. [10], [5]) highlight the importance of proper approaches for specifying said dynamic behavior.…”

“…In LOFAR, there were problems of missing or unclear systemlevel requirements as, back then, the system was a unique instrument concept, with unclear features yet to be discovered 8 [40], [41], [42]. Although in LOFAR2.0 the adoption of a more rigorous SE process, with a front-loading approach on requirements was aimed to address this, requirements-related problems persisted, but this time due to the domain knowledge required by software engineers to understand scientific use cases, a common issue also reported in [10]. Previous studies [11] highlighted the importance of interdisciplinary communication as a critical component of the process to avoid these kinds of problems.…”

“…To mitigate research bias in data analysis, three out of the four authors were involved in the data collection process, and came to an agreement through consensus building about the interpretations drawn from the analysis of the collected data. This process can be independently verified and traced back to the original quotes via the available replication package 10 .…”

“…that do not enforce such hierarchical system/subsystem structure, or even prescribe a non-hierarchical one (e.g., Event-Driven). Related work in this field [7], [8], [9], and recent practitioner surveys [10], [11] suggest that the gaps and mismatches between system-level and software-level architectures created by these interdisciplinary differences are linked to major integration and operation problems in many engineered systems, including SoS.…”