Lacking payment systems become a bottleneck for the vision of the Information Economy. In many cases payments of fractions of a cent, so-called micropayments, are of particular interest. In this paper we propose a framework to evaluate payment systems. The framework consists of a well structured...

We determine the increase of the maximum risk over the minimax risk in the case that the optimally robust estimator for the false radius is used. This is done by numerical solution of the implicit equations which determine optimal robustness, for location, scale, and linear regression models,...

When people decide about saving and consumption across the various periods of their life time they take into account their life expectancy when comparing present and future needs and resources for satisfying them. The experimental design, applied at two sites (Humboldt-University at Berlin and...

This paper proposes a model in which the removal of barriers to trade and factor mobility is associated with endogenous fragmentation of the value-added chain. Fragmentation is the outcome of cost competition - the profit-maximizing choice of cost structure by monopolistically competitive firms....

The authors develop and test a model to study the influence of inventory-on-hand and price-based reference points on the consumption rate of consumers. The model is motivated by recent theoretical and empirical research which suggests inventory pressure can cause consumers to increase...

In a complete financial market every contingent claim can be hedged perfectly. In an incomplete market it is possible to stay on the safe side by superhedging. But such strategies may require a large amount of initial capital. Here we study the question what an investor can do who is unwilling...

In this note the unobserved component approach underlying the software package SEATS is compared with the Beveridge-Nelson type of decomposition for seasonal time series. The main strength of the SEATS approach lies in the appealing model formulation and the careful specification and adjustment...