A fuzzy robustness measure for the scheduling of commissioned product development projects

摘要

Due to a considerable degree of uncertainty, the generation of robust schedules for the execution of product development projects is a crucial planning task. In the area of robust project scheduling, one basic option is to apply surrogate robustness measures as estimates of schedule robustness. Although project managers typically possess vague information about activity variations, most surrogate measures neglect this knowledge and are entirely based on deterministic data. In this contribution, we therefore present the "fuzzy overlap", that is, to the best of our knowledge, the first surrogate robustness measure for schedule stability which accounts for fuzzy activity duration. We provide a mathematical formulation and embed the fuzzy overlap in a two-stage planning approach for the scheduling of product development projects, which aims at balancing the minimization of project costs as the basic scheduling objective with the maximization of schedule robustness. In a numerical study, we compare the performance of our proposed approach with comparable deterministic surrogate robustness measures. The results indicate that the consideration of fuzzy information enhances schedule robustness compared to the application of traditional deterministic surrogate robustness measures. (C) 2019 Elsevier B.V. All rights reserved.