Traditional scheduling algorithms (using the techniques of PERT charts, decision analysis or operations research) require well-defined quantitative, complete sets of constraints. They are insufficient for scheduling situations where the problem description is ill-defined, involving incomplete, possibly inconsistent and generally qualitative constraints. The NUDGE program uses an extensive knowledge base to debug scheduling requests by supplying missing details and resolving minor inconsistencies. The result is that an informal request is converted to a complete description suitable for a traditional scheduler.
