We study a stochastic lead-time problem motivated by real world global shipping data. Replenishment quantities are generated by the Order-Up-To policy which aims to achieve a strategic availability target. We show that unlike the constant lead-time case, minimum safety stocks do not always lead to minimum costs under stochastic lead-times.

The paper concentrates on modeling the data that can be described by a homogeneous or non-homogeneous Poisson process. The goal is to decide whether the intensity of the process is constant or not. In technical practice, e.g., it means to decide whether the reliability of the system remains the same or if it is improving or deteriorating. We assume two situations. First, when only the counts of...

There is a growing consensus that a portfolio of customers with different demand lead times can lead to higher, more regular revenues and better capacity utilization. Customers with positive demand lead times place orders in advance of their needs, resulting in advance demand information. This gives rise to the problem of finding effective inventory control policies under advance demand informa...

In this first part of a two-part article, the principal characteristics of the TIMES model and of its global incarnation as ETSAP-TIAM are presented and discussed. TIMES was conceived as a descendent of the MARKAL and EFOM paradigms, to which several new features were added to extend its functionalities and its applicability to the exploration of energy systems and the analysis of energy and en...

We study single and multistage inventory systems with stochastic lead times. We study a class of stochastic lead time processes, which we refer to as exogenous lead times. This class of lead time processes includes as special cases all lead time models from existing literature (such as Kaplan’s lead times with no order crossing or independent and identically distributed lead times with order cr...

This paper discusses the issue of order crossover and its effects in order point, lot size (s, Q) inventory systems. Orders are likely to cross when their lead times are stochastic. Two inventory systems are considered to examine the consequences of order crossover. The first inventory system considers a fast moving item having deterministic demand and stochastic lead time. It is assumed lead t...

We consider a stochastic process driven by a diffusion and jumps. We devise a technique, which is based on a discrete record of observations, for identifying the times when jumps larger than a suitably defined threshold occurred. The technique allows also jump size estimation. We prove the consistency of a nonparametric estimator of the integrated infinitesimal variance of the process continuou...