Replanning in Predictive-reactive Scheduling

Abstract Achieving optimal results in real-life production scheduling is precluded by a number of problems. One such problem is dynamics of environments with unavailable resources (such as machine breakdowns and ill workers) and new demands (e.g. new orders) coming during the schedule execution. Traditional approach to react to unexpected events occurring on the shop floor is generating a new schedule from scratch. Complete rescheduling, however, may require excessive computation time. Moreover, the recovered schedule may deviate a lot from the ongoing schedule. Some work has focused on tackling these shortcomings, but none of the existing approaches tries to substitute jobs that cannot be executed with a set of alternative jobs. This paper reviews techniques related to predictive-reactive scheduling and suggests the future goal, which is to propose algorithms for dealing with unexpected events using the possibility of alternative processes