Implementing a loading heuristic in a discrete release job shop

The scheduling literature has developed two almost mutually exclusive problems; a static and a dynamic scheduling problem. The result has been that different tools have been developed to solve each problem. In this research, a model is developed such that it contains elements of both the static and the dynamic problems. This model, called here the discrete release model, considers the routing, loading, and release decisions as well as the customary sequencing decision evident in most job shop research. The objective of the research is to implement a method for examining tentative loading assignments prior to their release to the shop floor. The research develops a single pass, sequential routing and loading system. A heuristic is then developed that will enable jobs to be reloaded and rerouted prior to their start of processing. The system is tested in various shop environments to ascertain the effectiveness of this loading heuristic.