Paper accepted for publication
The paper "Resource-constrained multi-project scheduling with activity and time flexibility" by V.A. Haudera,b, A. Behama, S. Raggla, S.N. Parraghd and M. Affenzellerc,d has been accepted for publication in Computers & Industrial Engineering. The journal is ranked B according to the VHB journal ranking.
a Josef Ressel Center for Adaptive Optimization in Dynamic Environments, University of Applied Sciences Upper Austria, Hagenberg, Austria
b Institute of Production and Logistics Management, Johannes Kepler University, Linz, Austria
c Heuristic and Evolutionary Algorithms Laboratory, University of Applied Sciences Upper Austria, Hagenberg, Austria
d Institute of Formal Models and Verification, Johannes Kepler University, Linz, Austria
Abstract: 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.