Synthesizing SoS concepts for use in cost modeling

Today's need for more complex, capable systems in a short timeframe is leading many organizations towards the integration of existing systems into network-centric, knowledge-based system-of-systems (SoS). This presents new acquisition challenges in the area of cost estimation because of the lack of commonly accepted definitions and roles. Software and system cost models to date have focused on the software and system development activities of a single system. When viewing the new SoS architectures, one finds that the cost associated with the design and integration of these SoSs is not handled well, if at all, in current cost models. This paper looks at commonly cited definitions of SoS, then evaluates these definitions to determine if they adequately describe and converge on a set of SoS characteristics in the areas of product, development process, and development personnel that can be used to define boundaries and key parameters for an initial SoS cost model. Sixteen SoS definitions are synthesized to provide reasonable coverage for different properties of SoSs. Two examples are used to illustrate key characteristics relevant to cost modeling.