Simplicity, totality and change: a logistic viewpoint in inventory management
Abstract This paper demonstrates that even a simplified model works well when the model is revised from time to time. A new type of management problem results: easy-to-create models which cannot be validated.
The basic concepts of system dynamics optimization
This paper presents the fundamental concepts behind the use of heuristic optimization as a means of improving the behavior of systems as represented by system dynamics models. The philosophy of the approach is highlighted and the underlying software explained, as a prerequisite to developing some simple demonstration examples.
System dynamics and heuristic optimisation in defence analysis
The aim of this paper is to demonstrate the merits of using optimisation for policy design in system dynamics models. The approach has been applied to an existing defence model to design formation change strategies for an attacking force (Red) in response to indirect fire strategies applied by a defending force (Blue). The rationale behind the use of optimisation in system dynamics is presented, followed by a description of the optimisation software used. The model and its basic results are summarised, prior to describing the design and results of optimisation experiments applied to it. It is concluded that the optimisation approach can significantly contribute to the analysis by highlighting new interactions between the Red and Blue strategies. Originally Red's desire to stay in a fast-moving, highdensity formation was seen primarily as being based on facilitating recovery of lost speed and hence momentum, when Blue's fire ceased. Additionally, however, it is shown here that this strategy is preferable because it also minimises the time over which Red is exposed to Blue's fire.