A Hybrid Method for the Resource-Constrained Project Scheduling Problem with Hammock Activities and Strip Packing like Resource Constraints

摘要

This paper presents an improved hybrid algorithm for the resource-constrained project scheduling problem with hammock activities and strip packing like resource constraints. The concept of hammock activities plays a central role in project management. They are used to fill the time span between other "normal" activities since their duration cannot be calculated or estimated at the initial stage of project planning. In the proposed approach, a resource-constrained project is characterized by its "best" schedule, where best means a makespan minimal resource-constrained schedule for which the total hammock cost is minimal and the resource profiles approach the ideal rectangular shape as much as possible. In the improved model the activities are assigned to the same resource units over their processing times. The applied resource leveling-smoothing procedure tries to minimize the number of starting-restarting events of resource units on the set of resource-feasible activity movements fixing the makespan and the distance of the hammock hangers. In order to illustrate the essence and viability of the conception, we present detailed computational results for a medium size project instance with randomly generated hammock members.