A GERTS-Based Interactive Computer System for Analyzing Project Networks Incorporating Improvement Curve Concepts

Critical Path Method/Program Evaluation Review Technique (CPM/PERT) systems have basic shortcomings: 1. activity durations that cannot be modified to reflect improvement curve trends, 2. no way to evaluate the effects of storage limitations, 3. no way to accurately represent the situations which involve costs due to design changes or which necessitate use of alternative operations to get around crowding of bottleneck activities, 4. no allowance for operations which may or may not be performed on different units, and 5. unsuitability for handling important costs caused by material shortages, personnel turnover, and other factors which occur at different positions in a program's unit or time sequence. A system has been developed which furnishes new and more comprehensive modeling techniques not available in most CPM/PERT systems. To illustrate the results, a ship construction process is diagrammed using Graphical Evaluation and Review Technique (GERT) network symbolism. Cost improvement, storage capacity, and many other realistic cost concepts can be incorporated into a network model, which can operate either deterministically or stochastically. Finally, data base capabilities and data management routines have been developed to support the analysis capabilities. Figures.