Many seasonal macroeconomic time series are subject to changes in their means and variances over a long time horizon. In this paper we propose a general treatment for the modelling of time-varying features in economic time series. We show that time series models with mean and variance functions...

This discussion paper resulted in an article in the <I>Journal of the Royal Statistical Society Series A</I> (2008). Vol. 171, issue 1, pages 265-277.<P> Risk is at the center of many policy decisions in companies, governments and other institutions. The risk of road fatalities concerns local governments...</p></i>

This discussion paper resulted in an article in the <I>International Journal of Forecasting</I> (2014). Volume 30, pages 572-584.<P> We explore a new approach to the forecasting of macroeconomic variables based on a dynamic factor state space analysis. Key economic variables are modeled jointly with...</p></i>

We consider a model for a serial supply chain in which production, inventory, and transportation decisions are integrated, in the presence of production capacities and for different transportation cost functions. The model we study is a generalization of the traditional single-item economic...

We study strategic negotiation models featuring costless delay, general recognition procedures, endogenous voting orders, and finite sets of alternatives. Two examples show: 1. non-existence of stationary subgame-perfect equilibrium (SSPE). 2. the recursive equations and optimality conditions...

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 describe a Sequential Importance Sampling (SIS) procedure for counting the number of vertex covers in general graphs. The performance of SIS depends heavily on how close the SIS proposal distribution is to a uniform one over a suitably restricted set. The proposed algorithm...

One of the basic assumptions of the classical dynamic lot-sizing model is that theaggregate demand of a given period must be satisfied in that period. Under thisassumption, if backlogging is not allowed then the demand of a given period cannotbe delivered earlier or later than the period. If...