Maintaining systems-of-systems fit-for-purpose: a technique exploiting material, energy and information source, sink and bearer analysis

Across many domains, systems suppliers are challenged by the complexity of their systems and the speed at which their systems must be changed in order to meet the needs of customers or the societies which the systems support. Stakeholder needs are ever more complex: appearing, disappearing, changing and interacting faster than solutions able to address them can be instantiated. Similarly, the systems themselves continually change as a result of both external and internal influences, such as damage, changing environment, upgrades, reconfiguration, replacement, etc. In the event of situations unforeseen at design time, personnel (for example maintainers or operators) close to the point of employment may have to modify systems in response to the evolving situation, and to do this in a timely manner so that the system and/or System-of-Systems (SoS: a set of systems that have to interoperate) can achieve their aims. This research was motivated by the problem of designing-in re-configurability to the constituent systems of a SoS to enable the SoS and its systems to effectively and efficiently counter the effects of unforeseen events that adversely affect fitness-for purpose whilst operational. This research shows that a SoS does not achieve or maintain fitness-for-purpose because it cannot implement the correct, timely and complete transfer of Material, Energy and Information (MEI) between its constituents and with its external environment that is necessary to achieve a desired outcome; i.e. the purpose.