Multi-project scheduling problems are characterized by the way resources are
managed in the problem environment. The general approach in multi-project
scheduling literature is to consider resource capacities as a common pool that
can be shared among all projects without any restrictions or costs. The way
the resources are used in a multi-project environment is called resource management policy and the aforementioned assumption is called Resource Sharing
Policy in this study. The resource sharing policy is not a generalization
for multi-project scheduling environments and different resource management
policies maybe defined to identify characteristics of different problem environments.
In this study, we present a resource management policy which prevents sharing of resources among projects but allows resource transfers when a project starts after the completion of another one. This policy is called the Relaxed Resource Dedication (RRD) Policy in this study. The general resource capacities might or might not be decision variables. We will treat here the case where the general available amounts of resources are decision variables to be determined subject to a limited budget. We call this problem as the Resource Portfolio Problem (RPP). In this study, RPP is investigated under RRD policy and a modified Branch and Cut (B&C)procedure based on CPLEX is proposed. The B&C procedure of CPLEX is modified with different branching strategies, heuristic solution approaches and valid inequalities. The computational studies presented demonstrate the effectiveness of the proposed solution approaches
