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Kato A.,Ruhr West University of Applied Sciences | Burger S.,Zuse Institute Berlin | Burger S.,JCMwave GmbH | Scholze F.,Physikalisch - Technische Bundesanstalt
Applied Optics | Year: 2012

The influence of edge roughness in angle-resolved scatterometry at periodically structured surfaces is investigated. A good description of the radiation interaction with structured surfaces is crucial for the understanding of optical imaging processes such as, e.g., in photolithography. We compared an analytical two-dimensional (2D) model and a numerical three-dimensional simulation with respect to the characterization of 2D diffraction of a line grating involving structure roughness. The results show a remarkably high agreement. The diffraction intensities of a rough structure can therefore be estimated using the numerical simulation result of an undisturbed structure and an analytically derived correction function. This work allows to improve scatterometric results for the case of practically relevant 2D structures. © 2012 Optical Society of America. Source

Bumiller G.,Ruhr West University of Applied Sciences
2012 IEEE International Symposium on Power Line Communications and Its Applications, ISPLC 2012 | Year: 2012

High speed narrow band power line communication (NB-PLC) seems to be the favored candidate for smart metering and smart grid applications on distribution lines. With more than a decade experience in this technology we have now the chance to design a new system from the scratch. This paper focus on a requirement and experience based design for the transmit signals of a NB-PLC system. After a requirement analyses proposals were done and motivated for synchronization, modulation, peak to average reduction and windowing. © 2012 IEEE. Source

Jansen M.,Ruhr West University of Applied Sciences
CLOSER 2012 - Proceedings of the 2nd International Conference on Cloud Computing and Services Science | Year: 2012

In recent years, the number of reasonable powerful mobile devices increased. In 2011, the number of smartphone (e.g.) increased to more than 300 million units. A lot of research has already been conducted with respect of mobile devices acting as Cloud Service consumers, but still not much effort is put on mobile devices in the role of Cloud Service providers. Therefore, this paper presents an approach that allows to utilize mobile devices like smart phones or tablets as Cloud Service providers. In order to make this a reasonable approach, some of the occurring problems are discussed and it is shown how the presented architecture is able to overcome these problems. Last but not least, this paper describes some performance tests of the chosen implementation for mobile Web Services. Source

Schaefer S.,Max Planck Institute for Human Development | Schellenbach M.,Ruhr West University of Applied Sciences | Lindenberger U.,Max Planck Institute for Human Development | Woollacott M.,University of Oregon
Experimental Brain Research | Year: 2014

When a cognitive and a motor task like walking or keeping one’s balance are performed concurrently, performance usually deteriorates. Older adults have often been shown to prioritize their motor performance in such dual-task situations, possibly to protect themselves from falls. The current study investigates whether these prioritization behaviors can still be observed when several challenges are combined. Younger (20–30 years old) and older adults (60–70 years old; n = 24 in each group) were asked to walk through virtual environments with and without a cognitive load (3-back task). Walking difficulty was increased by walking on an elevated surface or on a narrow as opposed to a broad track, or both. Walking instructions emphasized speed and accuracy (avoiding missteps). No instruction was given concerning which performance dimension should be prioritized during dual-task trials. Participants decreased their 3-back performance while walking. Younger adults maintained their walking speed on elevated surfaces and were able to keep the number of missteps low, even when walking on a narrow track while performing the cognitive task. Older adults increased their walking speed on elevated relative to even surfaces and committed more missteps under cognitive load. Results suggest that task prioritization might fail in healthy older adults if several challenges are combined in high-risk settings. © 2014, Springer-Verlag Berlin Heidelberg. Source

Hoffmann S.G.,Ruhr West University of Applied Sciences
2016 International Symposium on Power Line Communications and its Applications, ISPLC 2016 | Year: 2016

This paper describes the layer-2-security functions of two narrow-band power line communication standards, namely ITU-T G.9903 and IEEE 1901.2. We describe how access control, authentication, confidentiality and integrity for network devices are achieved in both standards. We compare the approaches by using two practice-oriented installation scenarios and by evaluating the security methods. © 2016 IEEE. Source

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