Complex technological artefacts are often decomposed into smaller components to keep their design manageable. The resulting challenge is to coordinate decisions that involve multiple components and to design components such that high-level targets are met. Analytical Target Cascading (ATC) is an analytical coordination method for the optimization of decomposed systems, which we aim to incorporate in systems engineering design process. To this extent, we relate the domain of engineering optimization to the domain of requirements engineering, and propose a method that constructs an ATC problem from functional specifications and requirements written in the newly developed Elephant Specification Language. The proposed method is demonstrated in the two-level design of an automotive powertrain. This contribution is a step towards design automation and is expected to increase the usability of decomposed optimization techniques.

The design of ITER, a large-scale nuclear fusion reactor, is intertwined with profound research and development efforts. Tough problems call for novel solutions, but the low maturity of those solutions can lead to unexpected problems. If designers keep solving such emergent problems in iterative design cycles, the complexity of the resulting design is bound to increase. Instead, we want to show designers the sources of emergent design problems, so they may be dealt with more effectively. We propose to model the interplay between multiple problems and solutions in a problem network. Each problem and solution is then connected to a dynamically changing engineering model, a graph of physical components. By analysing the problem network and the engineering model, we can (1) derive which problem has emerged from which solution and (2) compute the contribution of each design effort to the complexity of the evolving engineering model. The method is demonstrated for a sequence of problems and solutions that characterized the early design stage of an optical subsystem of ITER.

Tomorrow's big science systems are in development today. Success depends on global collaboration in which multiple international parties produce unique assemblies. Inter-organizational barriers, interests and technical conflicts often complicate the design and realization process. It is especially difficult to manage a system's interfaces over such boundaries. We propose a model-based approach to support integrators in such situations. Combining a system architecture model, Integration Readiness Levels (IRLs) and a network of actors, we can derive a newly introduced Collaborative Interface Risk Index (CIRI) that highlights risky interfaces, the organizational patterns that are required for successful integration and a progress indicator that tracks how many interfaces have been defined sufficiently. We demonstrate the method for one of ITER's diagnostic subsystems, which is being developed by six distributed organizations. The result is a Multi-Domain Matrix (MDM) that gives a complete overview on the complexity and risks of the collaborative engineering project.