It is possible for a project to start up again after an apparently successful completion because of the discovery of a number of problems. Such a situation is, however, somewhat uncommon and occurs only after significant problem discoveries.
For the model we are working with here this problem is not serious, since it is the dynamics before the project is completed that are of interest. In multistage projects, where more than one activity is taking place and there is resource sharing between activities, restarting a task can be a significant problem.
The way to represent this is almost the same as the formulation of the thermostat problem discussed in Chapter 8. If the project has been declared complete, we do not restart it unless things get very bad.
project is done = IF THEN ELSE(project was done :AND:
fraction complete > restart fraction,1,
IF THEN ELSE(fraction complete >= 1,1,0))
Units: Dmnl
project was done = DELAY_FIXED(project is done,0,0)
Units: Dmnl
restart fraction = 0.9
Units: Dmnl
