Resource-constrained multi-project scheduling with activity and time flexibility
This addresses scheduling challenges in manufacturing environments where flexibility and multiple projects are critical, but it appears incremental as it builds on existing flexible RCPSP frameworks.
The paper tackled the problem of scheduling multiple manufacturing projects with flexible activity selection and durations, introducing a new resource-constrained project scheduling problem that integrates these decisions and proposes new objectives like time and resource balance. It developed mixed integer and constraint programming models, solving benchmark instances to optimality and demonstrating real-world applicability with a large industry case.
Project scheduling in manufacturing environments often requires flexibility in terms of the selection and the exact length of alternative production activities. Moreover, the simultaneous scheduling of multiple lots is mandatory in many production planning applications. To meet these requirements, a new resource-constrained project scheduling problem (RCPSP) is introduced where both decisions (activity flexibility and time flexibility) are integrated. Besides the minimization of makespan, two new alternative objectives are presented: maximization of balanced length of selected activities (time balance) and maximization of balanced resource utilization (resource balance). New mixed integer and constraint programming (CP) models are proposed for the developed integrated flexible project scheduling problem. Benchmark instances on an already existing flexible RCPSP and the newly developed problem are solved to optimality. The real-world applicability of the suggested CP models is shown by additionally solving a large industry case.