We study optimality properties in finite samples for time-varying volatility models driven by the score of the predictive likelihood function. Available optimality results for this class of models suffer from two drawbacks. First, they are only asymptotically valid when evaluated at the...

We consider unobserved components time series models where the components are stochastically evolving over time and are subject to stochastic volatility. It enables the disentanglement of dynamic structures in both the mean and the variance of the observed time series. We develop a simulated...

This paper entertains the notion that disturbances on the demand side play a central role in our understanding of the Great Depression. In fact, from Euler equation residuals we are able to identify a series of unusually large negative demand shocks that appeared to have hit the U. S. economy...

We show in this article that fractionally integrated univariate models for GDP may lead to a better replication of business cycle characteristics. We firstly show that the business cycle features are clearly affected by the degree of integration as well as by the other short run components of...

In finance, durations between successive transactions are usually modelled by the autoregressive conditional duration model based on a continuous distribution omitting frequent zero values. Zero durations can be caused by either split transactions or independent transactions. We propose a...

Frequency of services and vehicle size are important policyinstruments of railway companies. Extending Mohring's basic'square root model' for frequencies, we arrive at more generalformulations for frequency, vehicle size and price underalternative regimes of welfare and profit optimisation. It...

The concept of resilience has received a great deal of attention in the past decades. Starting fromthe first fundamental definitions offered by Holling, Pimms and Perrings in an economic-ecologicalmodeling context, the present paper explores the ‘evolution’ of the resilience concept – as...

Environmental sustainability issues have in recent years received much attention from the side ofenvironmental scientists and economists. There is a broad recognition on the relevance of externaleffects in open and interacting spatial systems. It would be helpful if ecological economic...

International and interregional trade and transport are on the rise and hence, there is a clear needfor reliable estimates of transport flows. However, the available databases and estimation methodsare not yet satisfactory for analytical and predictive purposes.In this paper we explore the use...

The linear Gaussian state space model for which the common variance istreated as a stochastic time-varying variable is considered for themodelling of economic time series. The focus of this paper is on thesimultaneous estimation of parameters related to the stochasticprocesses of the mean part...