Overview of a flexible optimization approach to multi-resource, multi-project planning and scheduling

A complex multi-resource, multi-project management problem involving a wide range of decisions is addressed. Projects are composed of tasks which are further decomposed into sub-tasks. We employ a two-level hierarchical approach consisting of the planning and scheduling stages. The planning stage approaches the problem at a macro-level, enabling computation of schedules for tasks of projects, and incorporates resource leveling and smoothing capabilities. This stage has been formulated as a linear program, under a flexible optimization framework, which gives the user the choice of selecting among multiple objective functions and constraints that reflect today's dynamic and competitive environment. The output of the planning stage constitutes the input to the scheduling stage. This stage performs scheduling in detail at the sub-task level, adhering closely to the time and resource constraints imposed by the planning stage. Built into the model is some flexibility in the constraints for the scheduling stage, in order to meet expedition of projects where necessary, and to arrive at a final feasible schedule. The solution to the scheduling problem is computed by a Simulated Annealing algorithm. A user-friendly software package has also been developed. Flexibility, and soft constraints arising due to human factors and an easy-to-use software package are the major contributions of this work.