University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Population & European union. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

What are we talking about?—A taxonomy of computer simulations to support learning

Abstract: In this article a proposal for a taxonomy of computer simulations to support learning processes is presented. To achieve this goal, distinguishing criteria of computer simulations are identified and categorized. The work has been done in order to facilitate research about the evaluation of learning tools. The taxonomy is mainly built to be suitable for this objective, but can be of general help in establishing a common terminology. Sharing of findings and discussions among researchers from different fields can therefore by stimulated. Copyright © 2000 John Wiley & Sons, Ltd.

Systematic Risk in Recovery Rates - An Empirical Analysis of U.S. Corporate Credit Exposures

Abstract: This paper presents an analytical and empirical analysis of a parsimonious model framework that accounts for a dependence of bond and bank loan recoveries on systematic risk. We extend the single risk factor model by assuming that the recovery rates also depend on this risk factor and follow a logit?normal distribution. The results are compared with those of two related models, suggested in Frye (2000) and Pykhtin (2003), which pose the assumption of a normal and a log-normal distribution of recovery rates. We provide estimators of the parameters of the asset value process and their standard errors in closed form. For the parameters of the recovery rate distribution we also provide closed-form solutions of a feasible maximum-likelihood estimator for the three models. The model parameters are estimated from default frequencies and recovery rates that were extracted from a bond and loan database of Standard&Poor's. We estimate the correlation between recovery rates and the systematic risk factor and determine the impact on economic capital. Furthermore, the impact of measuring recovery rates from market prices at default and from prices at emergence from default is analysed. As a robustness check for the empirical results of the maximum-likelihood estimation method we also employ a method-of-moments. Our empirical results indicate that systematic risk is a major factor influencing recovery rates. The calculation of a default?weighted recovery rate without further consideration of this factor may lead to downward-biased estimates of economic capital. Recovery rates measured from market prices at default are generally lower and more sensitive to changes of the systematic risk factor than are recovery rates determined at emergence from default. The choice between these two measurement methods has a stronger impact on the expected recovery rates and the economic capital than introducing a dependency of recovery rates on systematic risk in the single risk factor model.

The Educational and Professional Background of Central Bankers and its Effect on Inflation - An Empirical Analysis

Abstract: We assume that central banks can control inflation so that inflation rates reflect the preferences of the central bank council. The hypothesis to be tested is that these preferences depend on the central bankers' educational and/or professional background. In a panel data analysis for the euro area and eleven countries since 1973, we explain inflation first by the weights which the various educational and professional characteristics occupy in the central bank council and second by the education or profession of the median central bank council member. Our results indicate that, with regard to professional background, former members of the central bank staff as well as former bankers and businessmen have the strongest inflation aversion and that former trade unionists and politicians seem to have the highest inflation preference. As for the education of the council members, our results are less robust. However, if the median member of the central bank council has studied business, the inflation rate is significantly lower than if she has studied economics.

Efficient Multidimensional Blocking for Link Discovery without losing Recall

Abstract: Over the last three years, an increasing number of data providers have started to publish structured data according to the Linked Data principles on the Web. The resulting Web of Data currently consists of over 28 billion RDF triples. As the Web of Data grows, there is an increasing need for link discovery tools which scale to very large datasets. In record linkage, many partitioning methods have been proposed which substantially reduce the number of required entity comparisons. Unfortunately, most of these methods either lead to a decrease in recall or only work on metric spaces. We propose a novel blocking method called MultiBlock which uses a multidimensional index in which similar objects are located near each other. In each dimension the entities are indexed by a dierent property increasing the efciency of the index signicantly. In addition, it guarantees that no false dismissals can occur. Our approach works on complex link specications which aggregate several dierent similarity measures. MultiBlock has been implemented as part of the Silk Link Discovery Framework. The evaluation shows a speedup factor of several 100 for large datasets compared to the full evaluation without losing recall.

Perceived foreign accent in first language attrition and second language acquisition: The impact of age of acquisition and bilingualism

Abstract: This study investigates constraints on ultimate attainment in second language (L2) pronunciation in a direct comparison of perceived foreign accent of 40 late L2 learners and 40 late first language (L1) attriters of German. Both groups were compared with 20 predominantly monolingual controls. Contrasting participants who acquired the target language from birth (monolinguals, L1 attriters) with late L2 learners, on the one hand, and bilinguals (L1 attriters, L2ers) with monolinguals, on the other hand, allowed us to disentangle the impacts of age of onset and bilingualism in speech production. At the group level, the attriters performed indistinguishably from controls, and both differed from the L2 group. However, 80% of all L2ers scored within the native (attriter) range. Correlational analyses with background factors further found some effects of use and language aptitude. These results show that acquiring a language from birth is not sufficient to guarantee nativelike pronunciation, and late acquisition does not necessarily prevent it. The results are discussed in the light of models on the role of age and cross-linguistic influence in L2 acquisition.