A unified formalism for complex systems architecture
Boris Golden · 2013
Complex industrial systems are typically artificial objects designed by men, involving a huge number of heterogeneous components (e.g. hardware, software, or human organizations) working together to perform a mission. In this thesis, we are interested in modeling the functional behavior of such systems, and their integration. We will model real systems as functional black boxes (with an internal state), whose structure and behaviors can be described by the recursive integration of heterogeneous smaller subsystems. Our purpose is to give a unified and minimalist semantics for heterogeneous integrated systems and their integration. By ``unified'', we mean that we propose a unified model of real systems that can describe the functional behavior of heterogeneous systems and that is closed under integration. By ``minimalist'' we mean that our formalization intends to provide a small number of concepts and operators to model the behaviors and the integration of complex industrial systems. Our work thus allows to give a relevant formal semantics to concepts and models typically used in Systems Engineering. In this framework, the integration of real systems can be modeled as a recursive process consisting in alternating composition and abstraction, to build a target overall system from elementary systems recursively composed and abstracted at different levels. Based on these definitions of systems and their integration, a minimalist systems architecture framework allows to deal with requirements, systems structure and underspecification during the design. In this thesis, we first define heterogeneous dataflows, and then systems as step-by-step machines transforming dataflows. Such systems can be integrated using operators, to build more complex systems, so that we can handle the two dimensions of the complexity (heterogeneity and integration). We then introduce a minimalist formalism for systems architecture to model requirements, underspecification \\& structure of systems through the design process. We finally open perspectives around systems optimization when fairness is required.