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The Simplex Optimization Methods

Evolutionary Operation (EVOP)

Evolutionary operation (EVOP) was introduced already in the 1950s by Box (see Box, 1957 and Box and Draper, 1969). The basic idea is to replace the static operation of a process by a continuous and systematic scheme of slight perturbations in the control variables. The effect of these perturbations is evaluated and the process is shifted in the direction of improvement.

The simplex method was originally developed for evolutionary operation, and is also very suitable for this purpose. It is easy to motivate people to use this approach since only a few starting trials are needed, and the simplex immediately moves away from unsuitable trial conditions.

The simplex method is especially appropriate when: 

• Process performance is changing over time.
• More than three control variables are to be perturbed.
• The process requires a fresh optimization with each new lot of material.

 

Literature

Spendley, W., Hext, G. R., Himsworth, F. R. Sequential application of simplex designs in optimisation and evolutionary operation. Technometrics 4(1962):4 441-461.

Box, G. E. P. Evolutionary operation: A method for increasing industrial productivity. Applied Statistics 6(1957) 81-101.

Box, G. E. P., Draper, N. R. Evolutionary operation. A statistical method for process improvement. John Wiley & Sons, 1969.

1. Simplex Introduction
2. The Basic Simplex Method
3. The Modified Simplex Method
4. Mixture Optimization

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