A local approach to automated correction of violated precedence and resource constraints in manually altered schedules

Users of automated scheduling systems frequently require an interactive approach to scheduling where they can manually modify the schedules. Because of complexity and cohesion of scheduling relations, it may happen that manual modification introduces flaws to the schedule, namely the altered schedule violates some constraints such as precedence relations or limited capacity of resources. It is useful to automatically correct these flaws while minimizing other required changes of the schedule. In this paper we suggest a fully automated approach to correcting violated precedence and unary resource constraints. The presented techniques attempt to alter minimally the existing schedule by doing the changes only locally in the area of the flaw.