A railway system needs a substantial amount of maintenance. To prevent unexpected breakdowns as much as possible, preventive maintenance is required. In this paper we discuss the Preventive Maintenance Scheduling Problem (PMSP), where (short) routine activities and (long) unique projects have to...

In this article we give an overview of the relation between planning of maintenance and production. On the one hand we consider production planning and scheduling models in which failures and maintenance aspects are taken into account. Next we discuss the planning of maintenance activities, for...

Experts possess knowledge and information that are not publicly available. The paper is concerned with the ranking of academic journal quality and research impact using a survey of experts from a national project on ranking academic finance journals. A comparison is made with publicly available...

We analyze the behavior of experts who quote forecasts for monthlySKU-level sales data where we compare data before and after the momentthat experts received different kinds of feedback on their behavior. Wehave data for 21 experts located in as many countries who make SKUlevelforecasts for a...

In this paper we examine two hypotheses concerning emigration. The first hypothesis is that emigration is positively correlated with wage differentials. The second hypothesis concerns a positive correlation between emigration and higher education in the sending country (the so-called brain gain...

Experts can rely on statistical model forecasts when creating their own forecasts.Usually it is not known what experts actually do. In this paper we focus on threequestions, which we try to answer given the availability of expert forecasts andmodel forecasts. First, is the expert forecast...

The median problem is a classical problem in Location Theory: one searches for a location that minimizes the average distance to the sites of the clients. This is for desired facilities as a distribution center for a set of warehouses. More recently, for obnoxious facilities, the antimedian was...

This paper deals with the analysis and evaluation of sales forecasts of managers, given that it is unknown how they constructed their forecasts. Our goal is to find out whether these forecasts are rational. To examine deviations from rationality, we argue that one has to approximate how the...

Delay management models determine which connections should be maintained in case of a delayed feeder train. Recently, delay management models are developed that take into account that passengers will adjust their routes when they miss a connection. However, for large-scale real-world instances,...

In this paper, we develop various calculus rules for general smooth matrix-valued functions and for the class of matrix convex (or concave) functions first introduced by Loewner and Kraus in 1930s. Then we use these calculus rules and the matrix convex function -log X to study a new notion of...