C. Dans-le-cas-où, les résultats des expériences 3 et 4 sont obtenus, respectivement, pour une contrainte de disponibilité (98.10%) et une contrainte de budget (5.45). D'après ces résultats, en minimisant le coût total moyen par unité de temps sous la contrainte de disponibilité, ce coût augmente de 5.31 à 5.36. Cette augmentation est due à la contrainte de disponibilité qui consiste à augmenter la disponibilité stationnaire du système de 97

1. De-même, en maximisant la disponibilité stationnaire du système sous la contrainte de budget, cette disponibilité diminue de 98.22% à 98.18%. Cette diminution est imposée par la contrainte de budget qui consiste à réduire le coût total moyen par unité de temps de 5

. Dans-le-cadre-de, montrent respectivement l'influence du coût C s sur le coût total moyen par unité de temps optimal J(? * ), la disponibilité stationnaire du système A s (? * ), et le taux de dégradation ?(? * ) La Figure 4.6 montre que l'augmentation du coût de pénurie C s engendre l'augmentation de la valeur optimale du coût total moyen par unité de temps J(? * ) En variant le coût C s de 0 à 375 la valeur optimale du coût total moyen par unité de temps augmente de 5.31 à 5.37. Ce résultat montre que le coût de pénalité C d a plus d'impact que le coût de pénurie C s sur la variation du coût total moyen par unité de temps optimal, ). La Figure 4.7 montre la disponibilité stationnaire du système A s (? * ) versus le coût de pénurie C s . Cette disponibilité est évaluée aux dates optimales d'inspection qui minimisent le coût total moyen par unité de temps J(?). L'augmentation du coût C s induit la diminution de la disponibilité stationnaire du système comme montré dans la Figure 4.7. La Figure 4

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