Technik für ein langes Leben

Megatrend Ambient Assisted Living - Im Jahr 2035 wird in Deutschland jeder dritte Mensch ?lter sein als 60 Jahre. Die Nachfrage nach Dienstleistungen und unterstützenden Systemen wird steigen. Technische Assistenzsysteme für Pflegende, Pflegebedürftige und deren Angeh?rige sollen das Leben im Alter sicherer und bequemer machen.     

Stock selection using a multi-factor model - empirical evidence from the French stock market

Using a Barra-type factor model, we have attempted to determine whether it is possible to beat the benchmark by taking advantage of anomalies established in the financial empirical literature. More specifically we have built an equity premium model based on three sets of factors (accounting variables, stock market characteristics and sector indicators) using a Bayesian method corrected for heteroscedasticity to estimate risk premiums, a technique that takes agents' learning into account. The results are encouraging: first, the factors that carried most weight on the equity premiums corroborated the results of empirical studies described in the financial literature, secondly, the portfolios constructed from our methodology and simulated outside our sample, returned higher performance than the benchmark and rewarded the supplement of volatility.     

Robust estimation of intraweek periodicity in volatility and jump detection

Opening, lunch and closing of financial markets induce a periodic component in the volatility of high-frequency returns. We show that price jumps cause a large bias in the classical periodicity estimators and propose robust alternatives. We find that accounting for periodicity greatly improves the accuracy of intraday jump detection methods. It increases the power to detect the relatively small jumps occurring at times for which volatility is periodically low and reduces the number of spurious jump detections at times of periodically high volatility. We use the series of detected jumps to estimate robustly the long memory parameter of the squared EUR/USD, GBP/USD and YEN/USD returns.     

Measuring and testing Granger causality over the spectrum: An application to European production expectation surveys

Decomposing Granger causality over the spectrum allows us to disentangle potentially different Granger causality relationships over different frequencies. This may yield new and complementary insights compared to traditional versions of Granger causality. In this paper, we compare two existing approaches in the frequency domain, proposed originally by Pierce [Pierce, D. A. (1979). R-squared measures for time series. Journal of the American Statistical Association, 74, 901–910] and Geweke [Geweke, J. (1982). Measurement of linear dependence and feedback between multiple time series. Journal of the American Statistical Association, 77, 304–324], and introduce a new testing procedure for the Pierce spectral Granger causality measure. To provide insights into the relative performance of this test, we study its power properties by means of Monte Carlo simulations. In addition, we apply the methodology in the context of the predictive value of the European production expectation surveys. This predictive content is found to vary widely with the frequency considered, illustrating the usefulness of not restricting oneself to a single overall test statistic.     

May business mentors act as opportunity brokers and enablers among university students?

Networks are recognized as a central component of the entrepreneurial process, in particular with regard to opportunity identification and exploitation. In this study, we specifically analyze the role of mentors who are in business as opportunity brokers and enablers among university students with entrepreneurial intentions. Our investigation on 1022 students from 13 French-language universities based in Canada, France, Belgium and Algeria indicates that mentors in business, contrary to other mentors, support opportunity identification and exploitation among university students. Although student gender, entrepreneurial experience and education have a more pronounced effect, mentoring is the only element that can be controlled for through the creation of formal support programs. These results call on public authorities, and universities in particular, to implement formal mentoring programs to support students who are interested in starting their own business, and who would not otherwise have access to business mentors in their environment.     

Do banks overstate their Value-at-Risk?

This paper is the first empirical study of banks’ risk management systems based on non-anonymous daily Value-at-Risk (VaR) and profit-and-loss data. Using actual data from the six largest Canadian commercial banks, we uncover evidence that banks exhibit a systematic excess of conservatism in their VaR estimates. The data used in this paper have been extracted from the banks’ annual reports using an innovative Matlab-based data extraction method. Out of the 7354 trading days analyzed in this study, there are only two exceptions, i.e. days when the actual loss exceeds the disclosed VaR, whereas the expected number of exceptions with a 99% VaR is 74. For each sample bank, we extract from historical VaRs a risk-overstatement coefficient, ranging between 19 and 79%. We attribute VaR overstatement to several factors, including extreme cautiousness and underestimation of diversification effects when aggregating VaRs across business lines and/or risk categories. We also discuss the economic and social cost of reporting inflated VaRs.