This discussion paper resulted in a publication in <A href="http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8239378&fulltextType=RA&fileId=S026996481000032X">'Probability in the Engineering and Informational Sciences'</A>, 25(2), 157-69.<p>A version of the classical secretary problem is studied, in which one is interested in selecting one of the <I>b</I> best out of a group of <I>n</I> differently ranked persons who are...</i></i></p></a>

In this paper we study Markov Decision Process (MDP) problems with the restriction that at decision epochs only a finite number of given Markovian decision rules may be applied. The elements of the finite set of allowed decision rules should be mixed to improve the performance. The set of...

The use of various moving average (MA) rules remains popular with financial market practitioners. These rules have recently become the focus of a number empirical studies, but there have been very few studies of financial market models where some agents employ technical trading rules of the type...

This discussion paper led to a publication in 'Social Choice and Welfare', 2005, 24, 439-454.<P> Many economic and social situations can be represented by a digraph. Both axiomatic and iterativemethods to determine the strength or power of all the nodes in a digraph have been proposed inthe...</p>

See also the publication in 'Journal of Mathematical Economics', 2008, 44, 1114-1125. <P> In this paper we describe the extreme points of two closely related polytopes that are assigned to a digraph. The first polytope is the set of all sharing vectors (elements from the unit simplex) such that...</p>

The first three factors resulting from a principal components analysis of term structure data are in the literature typically interpreted as driving the level, slope and curvature of the term structure. Using slight generalisations of theorems from total positivity, we present sufficient...

In this paper, we consider deterministic (both fluid and discrete) polling systems with N queues with infinite buffers and we show how to compute the best polling sequence (minimizing the average total workload). With two queues, the best polling sequence is always periodic when the system is...

This discussion paper resulted in a publication in 'Games and Economic Behavior', 2007, 59, 85-104. <P> We consider cooperative games with transferable utility (TU-games), in which we allow for a social structure on the set of players. The social structure is utilized to refine the core of the...</p>

A ranking method assigns to every weighted directed graph a (weak) orderingof the nodes. In this paper we axiomatize the ranking method that ranksthe nodes according to their outflow using four independent axioms. This outflowranking method generalizes the ranking by outdegree for directed...

Wetlands provide many important goods and services to human societies, and generate nonuse values as well. Wetlands are also very sensitive ecosystems that are subject to much stress from human activities. Reducing the stress on wetlands requires a spatial matching between physical planning,...