The fuzzy transform (F-transform), introduced by I. Perfilieva, is a powerful tool for the construction of fuzzy approximation models; it is based on generalized fuzzy partitions and it is obtained by minimizing a quadratic (L₂-norm) functional. In this paper we describe an analogous...

In credit risk modelling, method-of-moment approaches are popular to estimate latent asset return correlations within and between rating buckets. However, the autocorrelation that is often present in time series of default rates leads to systematically too low estimations. We propose a new...

Modern call centers require precise forecasts of call and e-mail arrivals to optimize staffing decisions and to ensure high customer satisfaction through short waiting times and the availability of qualified agents. In the dynamic environment of multi-channel customer contact, organizational...

In Lisbon the European Council proclaimed a European growth strategy. It considers an average economic u0093growth rate of around 3 percent as a realistic prospect for the coming yearsu0094 and assigns public finances an important role in the process of achieving this goal. This paper addresses...

We quantify the degree of persistence in unemployment rates of transition countries using a variety of methods benchmarked against the EU. In part of the paper, we work with the concept of linear u0093Hysteresisu0094 as described by the presence of unit roots in unemployment. Since this is...

In this paper we study the zero frequency spectral properties of fractionally cointegrated long memory processes and introduce a new frequency domain principal components estimator of the cointegration space and the factor loading matrix for the long memory factors. We find that for fractionally...

This paper addresses two important topics in recent economic historiography: globalization and the great divergence. We first present a search for statistical evidence in the Far East of an “Early Globalization” comparable to the one ongoing in the West since the mid-eighteenth century....

An alternative central limit theorem for martingale difference arrays is presented. It can be deduced from the literature but it is not stated as such. It can be very useful for statisticians and econometricians. An illustration is given in the context of ARMA models with time-dependent...

This paper extends our previous work on grain market integration across Europe and the Americas in the eighteenth and nineteenth centuries (Dobado, García-Hiernaux and Guerrero, 2012). By using the same econometric methodology, we now present: 1) a search for statistical evidence in the East of...

This study aims to capture volatility patterns using GARCH (1,1) models. It evaluates these models to obtain one-step-ahead forecastabilities by employing four major forecasting evaluation criteria, and compares two different currencies— the Pakistan rupee and the US dollar—as domestic and...