Suchergebnisse

AbstractThe problem of choosing an optimal replacement rule is considered for deteriorating equipment where the amount of deterioration is observed periodically. A "near" optimal rule is obtained. The main tool is an optimal stopping lemma related to semimartingales.

AbstractLet , where A (t)/t is nondecreasing in t, {P(k)1/k} is nonincreasing. It is known that H(t) = 1 — H(t) is an increasing failure rate on the average (IFRA) distribution. A proof based on the IFRA closure theorem is given. H(t) is the distribution of life for systems undergoing shocks occurring according to a Poisson process where P(k) is the probability that the system survives k shocks. The proof given herein shows there is an underlying connection between such models and monotone systems of independent components that explains the IFRA life distribution occurring in both models.

AbstractThis paper reconsiders the classical model for selling an asset in which offers come in daily and a decision must then be made as to whether or not to sell. For each day the item remains unsold a continuation (or maintenance cost)cis incurred. The successive offers are assumed to be independent and identically distributed random variables having an unknown distributionF. The model is considered both in the case where once an offer is rejected it may not be recalled at a later time and in the case where such recall of previous offers is allowed.