An evaluation of dispatching, due date, labor assignment, and input control policy decisions in a dual resource constrained job shop



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Texas Tech University


This study examines the interaction of dispatching, labor, due date assignment, and input control decision variables in the dual resource constrained (DRC) job shop. The DRC job shop is notably different from the machine-limited job shop in that labor is constrained as well as machinery. The majority of job shop scheduling research has assumed that labor was always available to process any job. This assumption does not portray the actual environment of most job shops. In reality, not all machines can be manned simultaneously, and labor is both a flexible and limiting resource. In addition, few studies have looked at due date assignment, or job releasing decisions within the DRC job shop.

The initial experiments examine the effectiveness of dispatching and due date assignment methods (under "loose" and "tight" due dates) in a DRC job shop. The contingent experiments are used to assess the effect of input control on the best dispatching and due date assignment policies, as determined by the initial experiments, for the DRC job shop. These operating policies are evaluated over five levels of due date tightness in the contingent experiments.

The findings of the initial experiments indicate that labor has a significant interaction with dispatching and due date rules. The results of the contingent experiments aiso indicate a significant interaction between input control strategies and due date assignment methods. The implications of this study suggest that the dependencies between the decision variables--dispatching; due date; labor; and input control--must be considered in order to develop an effective scheduling policy for the DRC job shop.