See also the article 'Mean and bold: on separating merger economies from structural efficiency gains in the drinking water sector' 2010, <I>The Journal of the Operational Research Society</I>, 61, 222-34.<P> The Dutch drinking water sector experienced two drastic changes over the last 10 years. Firstly,...</p></i>

We propose procedures for estimating the time-dependent transition matrices for the general class of finite nonhomogeneous continuous-time semi-Markov processes. We prove the existence and uniqueness of solutions for the system of Volterra integral equations defining the transition matrices,...

An intensive and still growing body of research focuses on estimating a portfolio’s Value-at-Risk.Depending on both the degree of non-linearity of the instruments comprised in the portfolio and thewillingness to make restrictive assumptions on the underlying statistical distributions, a...

A growing number of empirical studies provides evidence that dynamic properties of macroeconomic time series have been changing over time. Model-based procedures for the measurement of business cycles should therefore allow model parameters to adapt over time. In this paper the time dependencies...

This paper proposes a new set of transformed polynomial functions that provide a flexible setting for nonlinear autoregressive modeling of the conditional mean while at the same time ensuring the strict stationarity, ergodicity, fading memory and existence of moments of the implied stochastic...

This discussion paper resulted in an article in the <I>Oxford Bulletin of Economics and Statistics</I> (2008). Vol. 70 issue 1, pages 23-51.<P> This paper investigates business cycle relations among different economies in theEuro area. Cyclical dynamics are explicitly modelled as part of a time series...</p></i>

Most of the available monthly interest data series consist of monthlyaverages of daily observations. It is well-known that this averaging introduces spurious autocorrelation effectsin the first differences of the series. It isexactly this differenced series we are interested in when...

This discussion paper resulted in a publication in the <I>Journal of the Royal Statistical Society Series C</I> (2009). Vol. 58, pages 427-448.<I> Unobserved components time series models decompose a time series into a trend, a season, a cycle, an irregular disturbance, and possibly other components....</i></i>

This discussion paper resulted in an article in the <I>Journal of Financial Econometrics</I> (2012). Vol. 10, pages 354-389.<p> This paper considers spot variance path estimation from datasets of intraday high frequency asset prices in the presence of diurnal variance patterns, jumps, leverage effects and...</p></i>