| Today's need for more complex, more capable systems in a short timeframe is leading more organizations towards the integration of new and existing systems with commercial-off-the-shelf (COTS) products into network-centric, knowledge-based systems of systems (SoS). With this approach, system development processes to define the new architecture, identify sources to either supply or develop the required components, and eventually integrate and test these high level components are evolving and are being referred to as SoS Engineering (SoSE). In recent years, the systems engineering (SE) community has struggled to decide if SoSE is really different from traditional SE and, if it is different, how does it differ. Recent research and case studies [DoD, 2008] have confirmed that there are indeed key differences and that traditional SE processes are not sufficient for SoSE. However, as with any engineering discipline, how and how much SoSE differs depends on several factors. This research further investigated SoSE through the study of several large-scale SoSE programs and several SE programs that were considered part of one or more SoSs to identify key SoSE strategies and how these strategies differed based on SoS characteristics and constituent-systems. The results of these investigations were then captured in a system dynamics model that allows one to explore SoSE options with respect to engineering effort and return on SoSE investment. Two SoS capability development strategies (with and without an SoSE team to guide capability development) were compared and used to assess the value-added of the SoSE team with respect to total SE effort expended to engineer an SoS capability. It is clear from both the Office of the Secretary of Defense (OSD) pilot studies [DoD, 2008] and the system dynamics model analysis conducted as part of this research that there exist conditions under which investments in SoSE have positive and negative returns on investment. This dissertation provides the first quantitative determination of these conditions, and points out directions for future research that would strengthen the results. |
