Optimizing distributed design processes for flexibility and cost

This paper considers three different modes of design work that is distributed over several design parties: independent design (in parallel, no design interactions, sub-system requirements), dependent design (sequential, one-way design interactions, updated sub-system requirements) and interdependent design (in parallel or sequential, two-way design interactions, only system requirements). Each mode requires particular coordination strategies to be successful. One coordination strategy is based on requirement formulation: Both system and sub-system requirements are expressed as so-called solution spaces. Solution spaces represent sets of permissible designs where sub-system (or component) solution spaces can be deduced from the system solution space. The larger the size of a sub-system solution space, the more options for sub-system design decisions satisfying the overall system requirements exist and thus the larger the design flexibility. The three modes are applied to two industrial design problems and evaluated with respect to total flexibility and cost related to iteration steps, interactions between the design parties and requirement formulation. The resulting framework is applicable to general systems design problems.