A Unified View on Planning, Scheduling and Dispatching in Production Systems

Abstract: Planning, scheduling and dispatching play critical roles in the operations of a supply chain. Their definitions are clearly given through a unified view in this paper. The distinction between planning and scheduling is analyzed from the view point of microeconomics and queueing theory. The distinction between scheduling and dispatching is analyzed from the view point of computational complexity and hierarchical decomposition. Based on the elasticity of price and capacity, planning can be separated into demand planning or capacity planning. Scheduling period is the time horizon where price and average production cost are insensitive to the production rate. The critical roles of the master production schedule and move targets in job scheduling have been explained through the concept of hierarchical decomposition. Dispatching is the last layer of job scheduling in the hierarchical decomposition. The advantage of pull and push systems has been compared and analyzed systematically.