Comparative Study of Impedance Eduction Methods

The absorption efficiency of acoustic liners used in aircraft engines is characterized by the acoustic impedance. World wide, many grazing ow test rigs and eduction methods are available that provide values for that impedance. However, a direct comparison and assessment of the data of the di erent rigs and methods is often not possible because test objects and test conditions are quite di erent. Only a few papers provide a direct comparison. Therefore, this paper together with a companion paper, present data measured with a reference test object under similar conditions in the DLR and NASA grazing ow test rigs. Additionally, by applying the in-house methods Liner Impedance Non-Uniform ow Solving algorithm (LINUS, DLR) and Convected Helmhholtz Equation approach (CHE, NASA) on the data sets, similarities and differences due to underlying theory are identi ed and discussed

Kulturen des Kopierschutzes II

Seit den 1990er Jahren war viel die Rede von Kopie und Simulation, Re­produzier­barkeit und Serialität. Doch dass schon das eigene Portemon­naie Dinge wie Geld und Personalpapiere enthält, die nicht kopiert wer­den sollen und von Normal­bürgern auch nicht kopiert werden können, wird oft vergessen. Wir leben (auch) in einer "Kultur des Kopierschutzes", in der verschiedene technische, diskursive und juristische Verfahren zu­sammenwirken, um die gesteigerte "technische Repro­duzierbarkeit", um Benjamins berühmten Ausdruck zu bemühen, im Zaum zu halten. Besonders deutlich wird das auch in den manchmal aufgeregten Diskus­sionen um den Status des Urheberrechts im Feld der digitalen Medien. Die beiden Hefte der Navigationen des Jahres 2010 sind das Ergebnis einer von Prof. Dr. Jens Schröter (Medienwissenschaft,Theorie und Praxis multi­medialer Systeme) geleiteten Projektgruppe im Masterstudiengang "Medienkul­tur". Die Studierenden haben im Rahmen des gesetzten Themas selbstständig Problemstellungen formuliert und diskutiert, dieErgebnisse dieser Arbeit sind in den beiden Heften publiziert - zusammen miteiner Reihe eingeladener Beiträge, die Aspekte abdecken, die in der Projektgruppe nicht bearbeitet werden konn­te

A new validation scheme for the evaluation of multiparameter fields

On the basis of an extended cluster analysis algorithm, we present a new validation method for the evaluation of simulation experiments characterized by more than one parameter. This method allows the assessment of any parameter combination in space and time. As an example for the effectiveness of the algorithm, the results of two regional climate model runs and observational data have been tested and interpreted

Paula Hertwig – Genetikerin im 20. Jahrhundert: eine Spurensuche

Die Wissenschaftlerin Paula Hertwig (1889–1983) gehört neben der Physikerin Lise Meitner und der Botanikerin Elisabeth Schiemann zu den herausragenden weiblichen deutschen Gelehrten im 20. Jahrhundert. Sie ist Angehörige jener Generation, in der für Frauen nach der Durchsetzung des Frauenstudiums erstmals auch eine Karriere in Forschung und Lehre an den Universitäten möglich wurde. Paula Hertwig entstammte einer Gelehrtenfamilie und lebte jahrzehntelang mit ihrem Bruder, dem Anatomen Günther Hertwig (1888–1970), zusammen. Als Genetikerin am Berliner Institut für Vererbungsforschung erlebte sie zunächst den internationalen Aufbruch der Genetik, später die Verwicklung der Vererbungswissenschaft in die nationalsozialistische Rassenideologie und den Niedergang der Forschungsmöglichkeiten während der Kriegsjahre. Nach dem Ende des Zweiten Weltkrieges wurde sie an die Universität in Halle (Saale) berufen und hatte hier in verantwortlicher Position (als Dekanin bzw. Prodekanin einer Medizinischen Fakultät aus überwiegend bürgerlichen Professoren) die Auseinandersetzungen der Genetiker mit dem Lyssenkoismus, einer ideologiebasierten, sowjetischen Pseudotheorie, zu bestehen und sah sich mit politischen Verfolgungen von Studenten und Mitarbeitern der Martin-Luther-Universität in der sowjetischen Besatzungszone bzw. der frühen DDR konfrontiert. Ihre Forschungen trugen zur Erkenntnis des schädlichen Einflusses von Strahlen auf das Erbgut (speziell des Menschen) bei. Obwohl es keinen geschlossenen Nachlass von Paula Hertwig gibt, versucht die Biographie mit Hilfe vieler bisher noch unberücksichtigter Dokumente den besonderen Lebensweg von Paula Hertwig im spannungsvollen politischen Umfeld des 20. Jahrhunderts zu rekonstruieren

Complex networks for climate model evaluation with application to statistical versus dynamical modeling of South American climate

Acknowledgments: This paper was developed within the scope of the IRTG 1740/TRP 2011/50151-0, funded by the DFG/FAPESP. Furthermore, this work has been financially supported by the Leibniz Society (project ECONS), and the Stordalen Foundation (JFD). For certain calculations, the software packages pyunicorn (Donges et al. 2013a) and igraph (Csa´rdi and Nepusz 2006) were used. The authors would like to thank Manoel F. Cardoso, Niklas Boers, and the reviewers for helpful comments on the manuscript. Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Peer reviewedPostprin

Projections of global warming-induced impacts on winter storm losses in the German private household sector

We present projections of winter storm-induced insured losses in the German residential building sector for the 21st century. With this aim, two structurally most independent downscaling methods and one hybrid downscaling method are applied to a 3-member ensemble of ECHAM5/MPI-OM1 A1B scenario simulations. One method uses dynamical downscaling of intense winter storm events in the global model, and a transfer function to relate regional wind speeds to losses. The second method is based on a reshuffling of present day weather situations and sequences taking into account the change of their frequencies according to the linear temperature trends of the global runs. The third method uses statistical-dynamical downscaling, considering frequency changes of the occurrence of storm-prone weather patterns, and translation into loss by using empirical statistical distributions. The A1B scenario ensemble was downscaled by all three methods until 2070, and by the (statistical-) dynamical methods until 2100. Furthermore, all methods assume a constant statistical relationship between meteorology and insured losses and no developments other than climate change, such as in constructions or claims management. The study utilizes data provided by the German Insurance Association encompassing 24 years and with district-scale resolution. Compared to 1971–2000, the downscaling methods indicate an increase of 10-year return values (i.e. loss ratios per return period) of 6–35 % for 2011–2040, of 20–30 % for 2041–2070, and of 40–55 % for 2071–2100, respectively. Convolving various sources of uncertainty in one confidence statement (data-, loss model-, storm realization-, and Pareto fit-uncertainty), the return-level confidence interval for a return period of 15 years expands by more than a factor of two. Finally, we suggest how practitioners can deal with alternative scenarios or possible natural excursions of observed losses

Reliability of regional climate model simulations of extremes and of long-term climate

We present two case studies that demonstrate how a common evaluation methodology can be used to assess the reliability of regional climate model simulations from different fields of research. In Case I, we focused on the agricultural yield loss risk for maize in Northeastern Brazil during a drought linked to an El-Niño event. In Case II, the present-day regional climatic conditions in Europe for a 10-year period are simulated. To comprehensively evaluate the model results for both kinds of investigations, we developed a general methodology. On its basis, we elaborated and implemented modules to assess the quality of model results using both advanced visualization techniques and statistical algorithms. Besides univariate approaches for individual near-surface parameters, we used multivariate statistics to investigate multiple near-surface parameters of interest together. For the latter case, we defined generalized quality measures to quantify the model's accuracy. Furthermore, we elaborated a diagnosis tool applicable for atmospheric variables to assess the model's accuracy in representing the physical processes above the surface under various aspects. By means of this evaluation approach, it could be demonstrated in Case Study I that the accuracy of the applied regional climate model resides at the same level as that we found for another regional model and a global model. Excessive precipitation during the rainy season in coastal regions could be identified as a major contribution leading to this result. In Case Study II, we also identified the accuracy of the investigated mean characteristics for near-surface temperature and precipitation to be comparable to another regional model. In this case, an artificial modulation of the used initial and boundary data during preprocessing could be identified as the major source of error in the simulation. Altogether, the achieved results for the presented investigations indicate the potential of our methodology to be applied as a common test bed to different fields of research in regional climate modeling