The non-stationary gamma process is a non-decreasing stochastic process with independent increments. By this monotonic behavior this stochastic process serves as a natural candidate for modelling time-dependent phenomena such as degradation. In condition-based maintenance the first time such a...

Steel structures such as bridges, tanks and pylons are exposed to outdoor weathering conditions. In order to prevent them from corrosion they are protected by an organic coating system. Unfortunately, the coating system itself is also subject to deterioration. Imperfect maintenance actions such...

In this paper we introduce robust versions of the classical static and dynamic single leg seat allocation models as analyzed by Wollmer, and Lautenbacher and Stidham, respectively. These robust models take into account the inaccurate estimates of the underlying probability distributions. As...

In this paper we analyse the effect of satisfying in a different way customers with an order larger than a prespecified cutoff transaction size, in a simple newsboy setting. For compound Poisson demand with discrete order sizes, we show how to determine the expected costs and the optimal cutoff...

We discuss a class of risk measures for portfolio optimization with linear loss functions, where the random returns of financial instruments have a multivariate elliptical distribution. Under this setting we pay special attention to two risk measures, Value-at-Risk and Conditional-Value-at-Risk...

Several approaches exist to model decision making under risk, where risk can be broadly defined as the effect of variability of random outcomes. One of the main approaches in the practice of decision making under risk uses mean-risk models; one such well-known is the classical Markowitz model,...

During the last two decades, many heuristic procedures for the joint replenishment problem have appeared in the literature. The only available optimal solution procedure was based on an enumerative approach and was computationally prohibitive. In this paper we present an alternative optimal...

In multi-echelon distribution systems it is usually assumed that demand is only satisfied from the lowest echelon. In this paper we will consider the case where demand can be satisfied from any level in the system. However, then the problem arises of how to allocate orders from customers to the...

A maintenance activity carried out on a technical system often involves a system-dependent set-up cost that is the same for all maintenance activities carried out on that system. Grouping activities thus saves costs since execution of a group of activities requires only one set-up. By now, there...

In this paper we verify the conditions under which the marginal cost approach of Berg (1980, 1995) holds. As observed by Aven and Dekker (1996) the validity of the marginal cost approach gives rise to a useful framework of single component maintenance optimization models which covers almost all...