Open Access

Mit dem vorliegenden Band verabschiedet die Fachhochschule Bonn-Rhein-Sieg sich von ihrem langjährigen Gründungsrektor Prof. Dr. Wulf Fischer. Dank seiner nachhaltigen Arbeit hat sich diese Hochschule weit über die Region hinaus einen Namen gemacht. Neben der Lehre kommt der Forschung inzwischen ein großer Stellenwert zu. Die Forschungsthemen spiegeln die Fachbereiche wider: Wirtschaftswissenschaften, Informatik sowie Elektrotechnik, Maschinenbau und Technikjournalismus am Campus Sankt Augustin; am Campus Rheinbach die Fachbereiche Wirtschaft und Angewandte Naturwissenschaften, am Campus Hennef der Fachbereich Sozialversicherung sowie das zentrale Institut für Existenzgründung und Mittelstandsförderung in Sankt Augustin. Die Fachhochschule unterstützt ihre Professorinnen und Professoren bei ihren Forschungsprojekten von Beginn an und setzt auf die Gleichrangigkeit von Forschung und Lehre als strategisches Ziel. Erfolge bei der Einwerbung von Drittmitteln und anwendungsbezogene Projekte mit Unternehmen belegen dies. Einen Überblick über die in jüngster Zeit erbrachten Forschungen und Innovationen bietet diese Publikation. Sie zeigt die Breite der Forschung, aber auch, in welchen Profilbereichen die Fachhochschule Bonn-Rhein-Sieg Forschungsspitzen hervorgebracht hat.

Einer Moderne in der Tradition der Aufklärung, zweckrational gestimmt und zum Pragmatischen geneigt, muß Repräsentatives verdächtig vorkommen. Die Verpflichtung zu einer Wahrheit, die um so lauterer erscheint, je schmuck- und glanzloser sie daherkommt, beargwöhnt das Repräsentative bestenfalls als Schnickschnack, in weniger günstigen Stunden als Einschüchterung oder Manipulation.

Wann und warum bezeichnen wir die Erzeugnisse von Journalisten, PR-Beratern und Werbefachleuten als »professionell«? Was sind die Kriterien für »Professionalität« in den Kommunikationsberufen? Und wie haben sich die Vorstellungen davon in den vergangenen Jahrzehnten geändert? Die aktuellen Umbrüche unseres Mediensystems sind Anlass, dem Begriff und den Bedeutungen professioneller Kommunikation in historischer und systematischer, in theoretischer und pragmatischer Perspektive nachzugehen.

High peak to average power ratio (PAPR) of a transmitted signal is one of the major drawbacks of the complex wavelet packet modulation (CWPM) as usual in any multicarrier communication system. Utilizing the advantage of concentrating the energy to certain subspaces of the discrete wavelet transform, many PAPR reduction techniques are proposed to solve this problem like threshold and clipping methods. In this paper a novel hybrid PAPR reduction method for CWPM called Threshold-Clipping (TC) method has been proposed. The simulation results in Rayleigh multipath fading channel show that the proposed scheme has achieved 4.5 dB and 3 dB reduction in PAPR over the traditional threshold and clipping methods respectively with less than 0.5 dB degradation in bit error probability.

The requirements of an efficient communication scheme for wireless sensing applications have been investigated. The noncoherent direct chaotic communication scheme called chaos on-off keying (COOK) has presented itself as a promising candidate. This paper proposes a modified version of the COOK scheme to improve its performance in noisy and fading environments. The proposed scheme is designed to increase the signal space of the decision variable by using the concept of differential correlation keeping implementation requirements simple. The results show that the proposed modified version of the COOK scheme achieves less bit-error probability in noisy and fading channels at moderate signal-to-noise ratio values and almost constant detection threshold as compared with the original version.

The main requirements of efficient steganographic systems are transparency, robustness and security. In this work, the proposed system is designed to achieve these requirements, as follows: to increase the transparency and robustness, the proposed system uses the transform domain technique, in this case the wavelet domain technique to embed the color secret image into the color cover image. To achieve high security, chaotic systems are used to accomplish the following two purposes: firstly to scramble the secret color image before hiding it into the color cover image, secondly to randomly select the embedding positions in the cover image. Three chaotic systems with many combinations are used for the scrambling and the embedding process. Experimental results including Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), Correlation, Signal to Noise Ratio (SNR) and embedding capacity demonstrate that the proposed system has good performance as compared with other existing methods without attack and under different types of attacks such as filtering and noise attacks. Simulation results show that the combination of chaotic systems providing the best performance include the use of Logistic and Hénon maps for the embedding process and Arnold's cat map for the encryption process. The MSE, PSNR, correlation, SNR and embedding capacity obtained in this case reach up to 0.0010, 78.1dB, 0.9999, 67.2dB and 0.39% respectively when the secret image is Airplane with 32×32 pixels and the cover image is Girl with 512×512 pixels. For the extracted secret image, the chaotic system set that provides the best performance includes the use of Arnold's cat map for the encryption process. The MSE, PSNR, correlation and SNR obtained in this case reach up to 0.0846, 58.9dB, 1 and 56.1dB respectively. As compared with other methods, the proposed method achieves gains without any attack of 8.2dB for the stego image and 32.4dB for the extracted secret image in PSNR when the secret image is Airplane with 256×256 pixels and the cover image is Girl with 512×512 pixels.

This paper describes a project carried out at the Bonn-Rhein-Sieg University to teach low-power digital design structures in a laboratory. Low-power design has become one of the most essential constraints in digital systems, especially in portable devices. For this purpose, low-power design is a topic addressed in electrical and computer curricula, but it also requires applications in a laboratory. Therefore, this project focuses on preparing students for current trends in low-power design by examining realistic applications of its basic theories and principles, either hands-on or remotely. The laboratory's experiments use a field programmable gate array (FPGA) as a design platform for implementing the students' digital designs. This contribution reports on our first experiences in teaching low-power design in the lab. This paper focuses on the educational impact on students regarding the following: (1) overall objectives in the laboratory, (2) experimental exercises with low-power techniques, and (3) using educational FPGA boards and the EduPow board. The EduPow board is a developed hands-on board at the Bonn-Rhein-Sieg University that is relatively specific on using various signal image-processing applications to directly observe the power dissipation of a student's digital algorithm. Our assessment of the low-power design lab shows that the requirements and objectives of this project are fairly well satisfied. In addition, students' feedback indicates that using the EduPow board is more attractive and motivational in their work.

This paper investigates how learning objectives can be complemented by employing a remote system to improve teaching low-power digital circuits design. The low-power design laboratory system that has been developed at the Bonn-Rhine-Sieg University of Applied Sciences is composed of two laboratory types: the on-site (hands-on) and the remote laboratories to teach low-power techniques with laboratory exercises. This laboratory system enables online experiments that can be performed using physical instruments and obtaining real data. Digital circuit designers can observe the most influential factors in power dissipation during laboratory exercises in the on-site system and then use the remote laboratory to supplement investigating other factors. This contribution describes teaching activities performed during the Summer Semester 2015 using only the on-site system, and during the Summer Semester 2016 using the on-site and the remote systems. The assessment studies the achieved learning objectives, evaluates the laboratory reports with and without the support of the remote system, and analyses the students' use of the remote system. The assessment and the students' opinions provide positive feedback on this approach and verify that the remote laboratory system is a successful and effective complementary learning tool for remotely reusing the on-site laboratory and achieving additional learning objectives that cover most conceptual theories in low-power digital circuits design.

The paper presents the topological reduction method applied to gas transport networks, using contraction of series, parallel and tree-like subgraphs. The contraction operations are implemented for pipe elements, described by quadratic friction law. This allows significant reduction of the graphs and acceleration of solution procedure for stationary network problems. The algorithm has been tested on several realistic network examples. The possible extensions of the method to different friction laws and other elements are discussed.

Very large arrays of Microwave Kinetic Inductance Detectors (MKIDs) have the potential to revolutionize ground and space based astronomy. They can offer in excess of 10.000 pixels with large dynamic range and very high sensitivity in combination with very efficient frequency division multiplexing at GHz frequencies. In this paper we present the development of a 400 pixel MKID demonstration array, including optical coupling, sensitivity measurements, beam pattern measurements and readout. The design presented can be scaled to any frequency between 80 GHz and >5 THz because there is no need for superconducting structures that become lossy at frequencies above the gap frequency of the materials used. The latter would limit the frequency coverage to below 1 THz for relatively high gap materials such as NbTiN. An individual pixels of the array consist of a distributed Aluminium CPW MKID with an integrated twin slot antenna at its end. The antenna is placed in the in the second focus of an elliptical high purity Si lens. The lens-antenna coupling design allows room for the MKID resonator outside of the focal point of the lens. The best dark noise equivalent power of these devices is measured to be NEP = 7×10-19 W/[square root]Hz and the optical coupling efficiency is around 30%, in which no antireflection coating was used on the Si lens. For the readout we use a commercial arbitrary waveform generator and a 1.5 GHz FFTS. We show that using this concept it is possible to read out in excess of 400 pixels with 1 board and 1 pair of coaxial cables.

Salts and proteins comprise two of the basic molecular components of biological materials. Kosmotropic/chaotropic co-solvation and matching ion water affinities explain basic ionic effects on protein aggregation observed in simple solutions. However, it is unclear how these theories apply to proteins in complex biological environments and what the underlying ionic binding patterns are. Using the positive ion Ca2+ and the negatively charged membrane protein SNAP25, we studied ion effects on protein oligomerization in solution, in native membranes and in molecular dynamics (MD) simulations. We find that concentration-dependent ion-induced protein oligomerization is a fundamental chemico-physical principle applying not only to soluble but also to membrane-anchored proteins in their native environment. Oligomerization is driven by the interaction of Ca2+ ions with the carboxylate groups of aspartate and glutamate. From low up to middle concentrations, salt bridges between Ca2+ ions and two or more protein residues lead to increasingly larger oligomers, while at high concentrations oligomers disperse due to overcharging effects. The insights provide a conceptual framework at the interface of physics, chemistry and biology to explain binding of ions to charged protein surfaces on an atomistic scale, as occurring during protein solubilisation, aggregation and oligomerization both in simple solutions and membrane systems.