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  • Author: Thomas Zwick x
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Abstract

This paper provides evidence of the productivity effects of different continuing vocational training forms in Germany. Using the waves 1997-2001 of the IAB establishment panel, it is found that formal external courses have the largest positive impact on productivity. Formal internal courses and quality circles have a smaller positive impact. Self-induced learning, participation at seminars and talks and job rotation do not enhance productivity while training on the job has a negative productivity impact. Establishments with an inefficient production structure decide to offer training in order to boost productivity. This paper also shows that taking into account selectivity of the training decision, unobserved time-invariant heterogeneity, human resource practices, as well as establishment and employee characteristics has an important impact on the measurement results.

Summary

This paper analyses the skill supply consequences of skill biased technological change. In a simple microeconomic model it is shown that higher skill wage mark-ups as well as higher relative unskilled unemployment - frequently attributed to skill biased technological change - induce overqualification. Therefore over-qualification is an equilibrium mechanism when skill rents increase.

A shift-share analysis on the basis of representative German individual data (the Mikrozensus) shows indeed that the qualification levels for jobs with given characteristics increased between 1991 and 1995 in Germany. The job characteristics analysed are type of activity mainly pursued, place of activity or position in the enterprise. These findings are interpreted as evidence for increasing over-qualification in the wake of skill biased technological change.

Abstract

This paper analyses the effect of the economic crisis in the years 2008 and 2009 on individual training activities of different employee groups within establishments. We use a unique German linked employer–employee panel data set with detailed information on individual training history (WeLL-ADIAB). The so-called Great Recession can be seen as an exogenous, unexpected, and time-limited shock. Although our results cannot be interpreted in a strictly causal manner, our Diff-in-Diff analyses suggest a direct negative effect of the crisis on individual training activities in 2009 and 2010. The negative effect therefore sets in with a time lag and lasts until after the recession. Furthermore, the recession has a stronger effect for employees in unskilled jobs than for employees in skilled jobs.

Summary

This paper analyses the risk of unemployment, unemployment duration, and the risk of longterm unemployment immediately after apprenticeship graduation. Unemployed apprenticeship graduates constitute a large share of unemployed youth in Germany but unemployment incidence within this group is unequally distributed. Our paper extends previous research in three dimensions. It shows that (i) individual productivity assessment of the training firm, (ii) initial selection into high reputation training firms and occupations, and (iii) adverse selection of employer moving graduates are correlated with unemployment after apprenticeship graduation. The empirical evidence is obtained from the second longitudinal version of the linked employer-employee panel data from the IAB (LIAB). This large data set allows us to calculate the exact unemployment spell length of apprenticeship graduates. In addition, we can include individual, employer, occupation as well as industrial relation characteristics before and after apprenticeship graduation into our list of explanatory variables for unemployment risk. We show in several robustness checks that our results are remarkably stable when we vary the employees included in the sample, the definition of unemployment, and the list of explanatory variables.

Abstract

This paper presents a computationally effective approach for including dense multipath components in ray tracing simulations of ultra wideband (UWB) channels. Through a combination of a standard ray tracing model with a simple geometric-stochastic model realistic scenario-specific simulations are possible. The frequency and direction selectivity of the channel are reproduced accurately by the model. The structure and parameters of the stochastic part of the model are derived from measurements in the FCC-UWB frequency range. Compared to conventional ray tracing simulations the proposed model reduces considerably the differences between simulated and measured channel characteristics.

Abstract

This paper reports on the research activities during the first phase of the project Real100G.RF, which is part of the German Research Foundation (DFG) priority programm SPP1655. The project’s main objective is to research silicon-based wireless communication above 200 GHz to enable data rates in excess of 100 gigabit per second (Gbps). To that end, this paper presents a fully packaged 240 GHz RF transmitter front-end with power combining antenna in 0.13 μ m SiGe technology. The design of circuit building blocks, passives, antenna and high-speed packaging is discussed. Communication measurements show data rates of 8 Gbps with an EVM of 12.4% using 16-QAM, 24 Gbps with 26.5% EVM using QPSK and 30 Gbps with 27.9% EVM using 8-PSK.