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Schmitter E.D.,Osnabruck University of Applied Sciences
Advances in Radio Science | Year: 2012

More than 2 yr of continuously recorded signal amplitude data from the MSK transmitters NRK/TFK (37.5 kHz, Iceland) and NSY (45.9 kHz, Sicily) received at (52 N 8 E) in the time range from August 2009 to September 2011 are analyzed with regard to planetary wave activity. Wavelet analysis of the day/night amplitude ratio reveals clear evidence of quasi 16 day periods mainly during winter time as well as traces of 5 and 10 day periods on both paths. The amplitude ratio is well correlated to the typical stratospheric (10 hPa) seasonal temperature profile - more clearly to be seen on the northern path. The results are in line and an extension of manifold research with regard of ionospheric absorption phenomena caused by atmospheric wave activity. Continuous monitoring of transmitters in the 40 kHz frequency range proved as an inexpensive tool for investigating mesospheric response to forcing from below. © 2012 Author(s). Source

Schmitter E.D.,Osnabruck University of Applied Sciences
Natural Hazards and Earth System Science | Year: 2010

Recent observations endorse earlier measurements of time varying electric and magnetic fields generated by tornadoes and dust devils. These signals may provide a means for early warning but together with a proper modeling approach can also provide insight into geometry and dynamics of the vortices. Our model calculations show the existence of pressure resonances characterized as acoustic duct modes with well defined frequencies. These resonances not only generate infrasound but also modulate the charge density and the velocity field and in this way lead to electric and magnetic field oscillations in the 0.5-20-Hz range that can be monitored from a distance of several kilometers. Source

Cardoso J.M.P.,University of Porto | Diniz P.,University of Lisbon | Weinhardt M.,Osnabruck University of Applied Sciences
ACM Computing Surveys | Year: 2010

Reconfigurable computing platforms offer the promise of substantially accelerating computations through the concurrent nature of hardware structures and the ability of these architectures for hardware customization. Effectively programming such reconfigurable architectures, however, is an extremely cumbersome and error-prone process, as it requires programmers to assume the role of hardware designers while mastering hardware description languages, thus limiting the acceptance and dissemination of this promising technology. To address this problem, researchers have developed numerous approaches at both the programming languages as well as the compilation levels, to offer high-level programming abstractions that would allow programmers to easily map applications to reconfigurable architectures. This survey describes the major research efforts on compilation techniques for reconfigurable computing architectures. The survey focuses on efforts that map computations written in imperative programming languages to reconfigurable architectures and identifies the main compilation and synthesis techniques used in this mapping. ©2010 ACM. Source

Karnani F.,Osnabruck University of Applied Sciences | Karnani F.,Luneburg University
Journal of Technology Transfer | Year: 2013

The assumption that research findings provide the basis for spin-off projects at universities has been found up to now in literature and the practice. Supported by the theory of knowledge, the empirical study presented here shows that this idea is too limited. Only 45 % of spin-offs use codified research findings from the university, while 55 % use tacit knowledge that was acquired at the university. These spin-offs use knowledge beyond research findings, starting companies in the shadow of publications by academic institutions and drawing from the realm of tacit knowledge at universities. Tacit start-up knowledge is present in all scientific disciplines of universities; even the exploitation- and patent-oriented engineering sciences account for almost half of the start-ups. Start-ups based on tacit knowledge lead to both technology-oriented and service companies. They also do not differ from codified knowledge-based start-ups in the number of jobs that they create. The discovery of the tacit knowledge spin-offs as a phenomenon has an entire series of implications for the practice and research. The tacit start-up potential was not considered previously in the university promotion instruments and start-up consultancies. Furthermore, we can assume that tacit knowledge-based start-ups are only an initial indication of the innovation potential within the tacit realm of knowledge for universities and research institutes. © 2012 Springer Science+Business Media, LLC. Source

Schmitter E.D.,Osnabruck University of Applied Sciences
Annales Geophysicae | Year: 2011

Very low and low radio frequency (VLF/LF) propagation responds sensitively to the electron density distribution in the lower ionosphere (upper mesosphere). Whereas propagation paths crossing subpolar and polar regions are frequently affected by forcing from above by particle precipitations, mid-and lowlatitude paths let forcing from below be more prominent. Our observations (2009-2011) show, that the low frequency propagation conditions along the midlatitude path from Sicily to Germany (52° N 8° E) using the NSY 45.9 kHz transmitter (37° N 14° E) prove to be a good proxy of mesosphere planetary wave activity along the propagation path. High absorption events with VLF/LF propagation correlate to the well known winter time D-layer anomaly observed with high frequency (HF) radio waves. VLF/LF propagation calculations are presented which show that the radio signal amplitude variations can be modeled by planetary wave modulated collison frequency and electron density profiles. The other way around wave pressure amplitudes can be inferred from the VLF/LF data. © 2006 Author(s). Source

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