Intrinsic Meta-Modeling of Systems of Systems: A Study in Bridge Infrastructure Management

This dissertation builds on the premise that a system of systems must be modeled through multiple models to account for the multifarious perspectives and its sub-systems. The stakeholders associated with the various sub-systems can be managerially and operationally independent, resulting in a distributed and decentralized decision-making environment. The outcomes of the decentralized and interdependent decisions made in a single sub-system affect the states and objectives of the other interdependent sub-systems. To address this challenge, this dissertation presents a modeling framework that builds on the theory of Phantom System Models (PSM) intrinsic meta-modeling to enable the modeling and management of systems of systems through a multi-phase, multi-level, iterative and collaborative coordination process.

The contributions of this dissertation are threefold. First, it introduces an iterative, learn-as-you-go methodological process for the construction of cross-disciplinary models that represent different perspectives of a system of systems, and for their integration into a single meta-model through the use of shared states. Second, it provides theoretical discussion on the use of the intrinsic meta-model as an instrument for collaborative coordination of distributed and decentralized sub-systems’ decisions. Intrinsic meta-modeling coordination is defined as the iterative process for adjusting individual sub-system’s decisions and constraints in response to measurable and/or observable changes in shared states. Ideally, acceptable levels of shared states can be achievable by all stakeholders over the planning time horizon, while satisficing sub-systems’ local level objectives. Third, it demonstrates the viability of the developed theory and methodology in its application to the bridge infrastructure system of systems to examine the engineering and socio-economic implications of untimely or insufficient bridge maintenance. It is expected that the developed theory and methodology can be applied to other civil infrastructure systems of systems, thus addressing the recognized need for such approaches.

Other theoretical and practical implications associated with the developed modeling framework include the following:
(i) The developed process enables and motivates stakeholders who work in a decentralized fashion to identify, quantify, and explicitly model some common and conflicting interests and needs. The ultimate goal of the stakeholders is to adhere to satisficing policies that would be superior to competitive and un-coordinated policies made at the sub-system level without the meta-modeling contribution.
(ii) Given the evolving nature of objectives, interest groups, organizational, political and budgetary baselines, and requirements associated with interdependent sub-systems, the meta-model coordination assumes an even broader role by enabling all stakeholders and decision makers to plan for future emergent changes through collaborative and foresighted efforts. This would yield beneficial outcomes for all concerned parties, and distribute risk ownership among all involved stakeholders.