Scheduling of design projects with uncertain number of iterations

Design projects are typically broken down into inter-related tasks that are worked on by designers equipped with various resources. In the creative but uncertain design process, certain tasks may have to be iterated a few times to meet the design criteria, and this very often has major impact on designer/resource planning and on project completion. This paper presents a novel integer programming formulation for the scheduling of design projects with uncertain number of iterations. A combined Lagrangian relaxation and backward dynamic programming algorithm is developed to solve the problem with manageable complexity. Testing results demonstrate that good and robust schedules can be generated in computationally efficient manner