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6 Conclusions

In order to study the robustness of the optimal orders and expected gain, our paper considers the newsboy model and compares the optimal orders obtained from several distributions of the demand, among them the lognormal, normal and triangular ones. We have shown that using these models embodies extra assumptions that are likely beyond the actual knowledge we can extract from the data usually accessible in inventory problems. For example using a Gaussian assumes a low maths and no skewness, while using a lognormal law assumes a non obvious relation between maths and skewness.

We have also given a closed form of a bound for the cost of uncertainty, which appears to be linear in maths and the unit selling price.

In discussions about robustness, the triangular model appears to be useful, since it allows maths to reach maths and skewness maths to reach maths together with a more realistic appearance than the "two Dirac's" distributions. In any case, it is not clear if the usually used maths is the best measure of the dispersion that can be extracted from actual data and used in max-min discussions. Using the inter-means parameter defined as:

maths

appears to be interesting either.

This constatation has its importance when investigating how prices are fixed by the market for risky products: in the long run, the sellers will reorient their activity if they don't obtain in the average at least the average remuneration for their capital. Thus the final price must contain not only the costs and the usual remuneration, but also (at least) an insurance for the risks[Eeckhoudt 2002].


previous up next
Previous: 5 Practitioner's section Up: Robustness Analysis of Stochastic Next: Acknowledgments


douillet@ensait.fr
2006-03-25