System-of-Systems Viewpoint for System Architecture Documentation
This work addresses documentation gaps for SoS architects in integrating independently managed systems, but it is incremental as it builds on existing viewpoints.
The study evaluated an architecture documentation viewpoint for system-of-systems (SoS) to address SoS architect concerns about constituent systems, finding that an expert panel could answer most questions except those related to software deployment on platforms and networks, leading to a revision adding a Deployment Model.
Context: The systems comprising a system of systems (SoS) are inde- pendently acquired, operated, and managed. Frequently, the architecture documentation of these existing systems addresses only a stand-alone perspective, and must be augmented to address concerns that arise in the integrated SoS. Objective: We evaluated an architecture documentation viewpoint to address the concerns of a SoS architect about a constituent system, to support SoS design and analysis involving that constituent system. Method: We performed an expert review of documentation produced by applying the viewpoint to a system, using the active review method. Results: The expert panel was able to used a view constructed using the baseline version of the viewpoint to answer questions related to all SoS architect concerns about a constituent system, except for questions concerning the interaction of the constituent system with the platform and network infrastructure. Conclusions: We found that the expert panel was unable to answer certain questions because the baseline version of the viewpoint had a gap in coverage related to relationship of software units of execution (e.g., processes or services) to computers and networks. The viewpoint was revised to add a Deployment Model to address these concerns, and is included in an appendix.