A General Stock Control Formulation For Stock Management Problems Involving Delays and Secondary Stocks

摘要

It is well established that if the stock management formulation ignores the supply line delay, the behavior of the system can be quite oscillatory. There are naturally other types of delays in stock management problems such as information delays in decision processing and delays caused in controlling a primary stock indirectly via a secondary stock. But there exist no general decision rules in system dynamics that explicitly consider these different delays in stock management structures. In this research, we first investigate the implications of ignoring such indirect delays in the decision formulation. We show that the behavioral consequence of ignoring information delays or ignoring the delay implicit via secondary stock control is equivalent to ignoring the supply line delay in the standard case: large oscillations. Next we derive a general stock control heuristic that does take into account these more advanced types of delays and show that the result is a stabilized dynamic behavior. Finally, we implement our decision heuristic on an example involving all three types of delays, demonstrating the “generic” nature of the proposed formulation structure. The combined result is a significant improvement in the stability of the system, when compared against the standard policy that considers the supply line delays only.