Project scheduling under partially renewable resource constraints

We consider a generalization of the classical resource constrained project scheduling problem. We introduce so-called partially renewable resources by assuming for each resource a capacity on subsets of periods. The concept o f partially renewable resources is a fundamental tool in order to make, e.g ., timetabling and shift scheduling aspects, amenable to project scheduling . In addition, partially renewable resources serve to model complicated lab or regulations. Furthermore, they cover traditional renewable and nonrenewa ble resource constraints as special cases. We consider makespan minimization as objective. For the exact solution of t he problem we employ a basic enumeration scheme. Ln order to speed up conve rgence, we formulate bounds which take into account future resource consump tion of partially renewable resources. Moreover, we generalize the serial s cheduling scheme in order to get fast approximation methods. A rigorous assessment of the procedures is provided by solving ProGen insta nces generated under a full factorial test design. Besides the well-known p roblem parameters we employ additionally three parameters which control the generation of partially renewable resources.