Advanced Process Combinatorics, Inc., proposes an interactive scheduling system which integrates model based optimization with an electronic Gantt chart. This system (SMART++/IGS) will be a new component for the object-oriented model based optimization scheduling system, SMART++ (Scheduling and Material Resource Timing). As such, IGS will be integrated with RCSPec, an existing language for describing scheduling problems, and MILP++, an existing object-oriented mixed integer program optimizer. The main defining feature of IGS will be the coupling of the electronic Gantt chart to the underlying model based optimization algorithms. Users will be able to add a wide variety of constraints to the schedule using the graphical user interface. By clicking the mouse on a task in the Gantt chart the user will be able to fix the execution time, or the place of a task in a sequence. The optimizer will complete the schedule, building an optimized schedule around the pieces already specified by the user. In addition to the obvious advantages of user friendliness, this provides the user with detailed control over the optimization algorithm. The addition of constraints (partial schedule specification) will make the optimization problem smaller and thus, easier to solve. Such user guided problem simplification may be exploited as a method of rendering difficult problems solvable. This and advances in optimization algorithms and faster computers offer hope that interactive scheduling which utilizes rigorous model based optimization will be a deliverable commercial product in the next few years.
