by Philip Boxer
While following up on a NECSI and MIT ESD seminar, I came across this paper by Joel Moses on three different organizing ideologies for the design of large scale engineering systems. He summarizes the three as follows:
Such approaches are usually called design methodologies. We discuss the top-down structured methodology, the layered or platform-based methodology, and the network-based methodology. Such design methodologies are associated with organizational structures or architectures, such as tree-structured hierarchies, layered hierarchies and generic networks. We point out how these design methodologies relate to cultural attitudes toward engineering.
While the systems engineering ideology is still rooted in the ‘tree-structures’ of hierarchical decomposition, its more recent recognition of ‘directed’ and ‘acknowledged’ systems of systems (SoS) belong to the ‘platform-based architectures’ that fall comfortably under the canon of Product-Line Practices1. The challenge comes with the ‘network-based architectures’, in which layering becomes an emergent property of the network. The environments in which these architectures are to be found exhibit Ultra-Large-Scale characteristics, the forms of social organization being supported are collaborative and co-producing, and the architecture of the systems of systems supporting these environments themselves need to be collaborative.
The difference between the platform-based and network-based architectures is whether or not layering can be treated as an a priori property of the architecture. Network-based architectures enable the emergence of multiple forms of layering with respect to the multiple concurrent forms of collaboration that they support. There is no longer a direct relationship between design and predictable uses, rendering the design of network-based architectures asymmetric to the architectures of demand.
 Note, however, that the ‘platform-based architectures’ that fall under Product-Line Practices are restricted to supporting a one-sided relation to markets. They are to be further distinguished from the multi-sided platform architectures that are network-based that support multi-sided relations to demand. See what distinguished a platform strategy.