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First year Business Administration students tend to regard themselves as “non-computer scientists” and often have a lack of motivation about taking IT courses in general, either because they perceive them as too technical, too difficult or somewhat irrelevant. In an attempt to counteract this perception and increase the levels of engagement and willing attendance to class, we decided to flip the traditional lecture model and develop a new teaching and learning approach for the IT Fundamentals course using an open source Enterprise Resource Planning (ERP) system as the platform from which to draw the various underlying IT concepts and through which the relevant competences can be acquired.
This paper describes the implementation process of this new contextualized learning framework “IT via ERP” and the changes in the didactical methods to support it.
IPv6 over resource-constrained devices (6Lo) emerged as a de-facto standard for the Internet of Things (IoT) applications especially in home and building automation systems. We provide results of an investigation of the applicability of 6LoWPAN with RPL mesh networks for home and building automation use cases. The proper selection of Trickle parameters and neighbor reachable time-outs is important in the RPL protocol suite to respond efficiently to any path failure. These parameters were analyzed in the context of energy consumption w.r.t the number of control packets. The measurements were performed in an Automated Physical Testbeds (APTB). The results match the recommendation by RFC 7733 for selecting various parameters of RPL protocol suite. This paper shows the relationship between various RPL parameters and control traffic overhead during network rebuild. Comparative measurement results with Bluetooth Low Energy (BLE) in this work showed that 6Lo with RPL outperformed BLE in this use case with less control traffic overheads.
The Paper presents the design and development of a blended learning concept for an engineering course in the field of color representation and display technologies. A suitable learning environment is crucial for the success of the teaching scenario. A mixture of theoretical lectures and hands-on activities with practical applications and experiments, combined with the advantages of modern digital media is the main topic of the paper. Blended learning describes the didactical change of attendance periods and online periods. The e-learning environment for the online period is designed toward an easy access and interaction. Present digital media extends the established teaching scenarios and enables the presentation of videos, animations and augmented reality (AR). Visualizations are effective tools to impart learning contents with lasting effect. The preparation and evaluation of the theoretical lectures and the hands-on activities are stimulated and affects positively the attendance periods. The tasks and experiments require the students to work independently and to develop individual solution strategies. This engages and motivates the students, deepens the knowledge. The authors will present their experience with the implemented blended learning scenario in this field of optics and photonics. All aspects of the learning environment will be introduced.
Due to a controversial enrollment policy in most engineering programs at German Universities of Applied Sciences (UAS), many freshmen show very low school grades in key subjects like Math and Physics. Nevertheless they expect to be entertained in the lectures and get demotivated easily. Despite initial reservations, a cheer-and-challenge approach was developed for teaching Mechanics to freshmen having very diverse school grades. When tested, it showed astonishing results.
A crack opening stress equation for in-phase and out-of-phase thermomechanical fatigue loading
(2016)
In this paper, a crack opening stress equation for in-phase and out-of-phase thermomechanical fatigue (TMF) loading is proposed. The equation is derived from systematic calculations of the crack opening stress with a temperature dependent strip yield model for both plane stress and plane strain, different load ratios and different ratios of the temperature dependent yield stress in compression and tension. Using a load ratio scaled by the ratio of the yield stress in compression and tension, the equation accounts for the effect of the temperature dependent yield stress and the constraint on the crack opening stress. Based on the scaling relation established in this paper, Newman's crack opening stress equation for isothermal loading is enabled to predict the crack opening stress under TMF loading.
The M-Bus protocol (EN13757) is in widespread use for metering applications within home area and neighborhood area networks, but lacks a strict specification. This may lead to incompatibilities in real-life installations and to problems in the deployment of new M-Bus networks. This paper presents the development of a novel testbed to emulate physical Metering Bus (M-Bus) networks with different topologies and to allow the flexible verification of real M-Bus devices in real-world scenarios. The testbed is designed to support device manufacturers and service technicians in test and analysis of their devices within a specific network before their installation. The testbed is fully programmable, allowing flexible changes of network topologies, cable lengths and types. Itis easy to use, as only the master and the slaves devices have to be physically connected. This allows to autonomously perform multiple tests, including automated regression tests. The testbed is available to other researchers and developers. We invite companies and research institutions to use this M-Bus testbed to increase the common knowledge and real-world experience.
A Survey of Channel Measurements and Models for Current and Future Railway Communication Systems
(2016)
We present a videodensitometric quantification method for methadone in syrup, separated by thin-layer chromatography (TLC). The quantification is based on a derivation reaction with Dragendorf reagent. Measurements were carried out using a 16-bit flatbed scanner. The range of linearity covers two magnitudes of power using the Kubelka-Munk expression for data transformation. The separation method is inexpensive, fast, and reliable.
The paper recommends an approach to estimate effectively the probability of buffer overflow in high-speed communication networks, capable of carrying diverse traffic, including self-similar teletraffic, and supporting diverse levels of quality of service. Simulations with stochastic, long-range dependent self-similar traffic source models are conducted. A new efficient algorithm, based on a variant of the RESTART/LRE method, is developed and applied to accelerate the buffer overflow simulation in a finite buffer single server model under long-range dependent self-similar traffic load with different buffer sizes. Numerical examples and simulation results are shown
There is a growing trend for the use of thermo-active building systems (TABS) for the heating and cooling of buildings, because these systems are known to be very economical and efficient. However, their control is complicated due to the large thermal inertia, and their parameterization is time-consuming. With conventional TABS-control strategies, the required thermal comfort in buildings can often not be maintained, particularly if the internal heat sources are suddenly changed. This paper shows measurement results and evaluations of the operation of a novel adaptive and predictive calculation method, based on a multiple linear regression (AMLR) for the control of TABS. The measurement results are compared with the standard TABS strategy. The results show that the electrical pump energy could be reduced by more than 86%. Including the weather adjustment, it could be demonstrated that thermal energy savings of over 41% could be reached. In addition, the thermal comfort could be improved due to the possibility to specify mean room set-point temperatures. With the AMLR, comfort category I of the comfort norms ISO 7730 and DIN EN 15251 are observed in about 95% of occasions. With the standard TABS strategy, only about 24% are within category I.
Adaptive predictive control of thermo-active building systems (TABS) based on a multiple regression algorithm: First practical test. Available from: https://www.researchgate.net/publication/305903009_Adaptive_predictive_control_of_thermo-active_building_systems_TABS_based_on_a_multiple_regression_algorithm_First_practical_test [accessed Jul 7, 2017].
Agile Business Intelligence als Beispiel für ein domänenspezifisch angepasstes Vorgehensmodell
(2016)
Business-Intelligence-Systeme stellen durch ihre Unterstützung bei der Entscheidungsfindung für Unternehmen eine wichtige Rolle dar. Mit einer stetig dynamischeren Unternehmensumwelt geht daher die Anforderung nach der agilen Entwicklung dieser Systeme einher, so dass in der BI-Domäne zunehmend erfolgreich agile Methoden und Vorgehensmodelle eingesetzt werden. Die Weiterentwicklung und Anpassung von BI-Systemen ist dahingehend besonders, dass diese in der Regel langjährig gewachsenen Systemen und Strukturen betreffen, die strengen regulatorischen Rahmenbedingungen unterliegen, was eine Herausforderung für agile Vorgehensweisen darstellt. Wurden die Werte und Prinzipien des agilen Manifests [AM01] und die daraus abgeleiteten Methoden zu Beginn meist eins zu eins auf den Bereich BI übertragen, so hat sich das Verständnis von BI- Agilität als ganzheitliche Eigenschaft der BI im deutschsprachigen Raum etabliert, und agile Me- thoden wurden auf die Besonderheiten der BI-Domäne adaptiert. In diesem Beitrag werden BI-Agilität und Agile BI erläutert, ein Ordnungsrahmen für Maßnahmen zur Steigerung der BI-Agilität eingeführt sowie Herausforderungen bei Agile BI erläutert.
All business is local
(2016)
All you need is sleep
(2016)
In 21st century, the century when the humanity hopes to embark on interplanetary travel, we are yet to fully reach an understanding of our very own idiosyncratic terra incognita – the human sleep. Sleep is a highly conserved evolutionary process that constitutes approximately one third of our life, and the lack or inadequate sleep may lead to impairment across multiple cognitive domains (Tononi and Cirelli, 2014; Lim and Dinges, 2010). Sleep deprivation also leads to aberrant brain functioning, immunological and metabolic collapse, and if it is sufficiently prolonged it will ultimately lead to death (Tononi and Cirelli, 2014).
There is increasing evidence of central hyperexcitability in chronic whiplash-associated disorders (cWAD). However, little is known about how an apparently simple cervical spine injury can induce changes in cerebral processes. The present study was designed (1) to validate previous results showing alterations of regional cerebral blood flow (rCBF) in cWAD, (2) to test if central hyperexcitability reflects changes in rCBF upon non-painful stimulation of the neck, and (3) to verify our hypothesis that the missing link in understanding the underlying pathophysiology could be the close interaction between the neck and midbrain structures. For this purpose, alterations of rCBF were explored in a case-control study using H215O positron emission tomography, where each group was exposed to four different conditions, including rest and different levels of non-painful electrical stimulation of the neck. rCBF was found to be elevated in patients with cWAD in the posterior cingulate and precuneus, and decreased in the superior temporal, parahippocampal, and inferior frontal gyri, the thalamus and the insular cortex when compared with rCBF in healthy controls. No differences in rCBF were observed between different levels of electrical stimulation. The alterations in regions directly involved with pain perception and interoceptive processing indicate that cWAD symptoms might be the consequence of a mismatch during the integration of information in brain regions involved in pain processing.
n this work a mathematical model for describing the performance of lithium-ion battery electrodes consisting of porous active material particles is presented. The model represents an extension of the Newman-type model, accounting for the agglomerate structure of the active material particles, here Li(Ni1/3Co1/3Mn1/3)O2 (NCM) and Li(Ni1/3Co1/3Al1/3)O2 (NCA). To this goal, an additional pore space is introduced on the active material level. The space is filled with electrolyte and a charge-transfer reaction takes place at the liquid-solid interface within the porous active material particles. Volume-averaging techniques are used to derive the model equations. A local Thiele modulus is defined and provides an insight into the potentially limiting factors on the active material level. The introduction of a liquid-phase ion transport within the active material reduces the overall transport losses, while the additional active surface area within the agglomerate lowers the charge-transfer resistance. As a consequence, calculated discharge capacities are higher for particles modeled as agglomerates. This finding is more pronounced in the case of high C-rates
A number of design rules must be adhered to in the development and manufacturing of unmanned aerial vehicles. In this, additive manufacturing, particularly in the implementation of requirements with respect to light-weight construction and sustainability, offers several advantages compared to conventional manufacturing methods. Therefore, this article will primarily introduce and compare current concepts for sustainable design using additive manufacturing. These will, above all, consist of the production of complete fuselages and wings by means of rapid prototyping or also rapid tooling. In addition, a new concept will be introduced in which a UAV using AM can be implemented through the combination of very light components and a preferably resource-saving manufacturing method. In this process, a three-dimensional spaceframe is used in combination with a covering in the construction of the wing. Hereby, the development process for sustainable design using additive manufacturing will be analyzed and the results will be explained by means of concrete case studies. In conclusion, the results of these case studies will be compared to the latest technology regarding wing span load.
In the age data digitalization, important applications of optics and photonics based sensors and technology lie in the field of biometrics and image processing. Protecting user data in a safe and secure way is an essential task in this area. However, traditional cryptographic protocols rely heavily on computer aided computation. Secure protocols which rely only on human interactions are usually simpler to understand. In many scenarios development of such protocols are also important for ease of implementation and deployment. Visual cryptography (VC) is an encryption technique on images (or text) in which decryption is done by human visual system. In this technique, an image is encrypted into number of pieces (known as shares). When the printed shares are physically superimposed together, the image can be decrypted with human vision. Modern digital watermarking technologies can be combined with VC for image copyright protection where the shares can be watermarks (small identification) embedded in the image. Similarly, VC can be used for improving security of biometric authentication. This paper presents about design and implementation of a practical laboratory experiment based on the concept of VC for a course in media engineering. Specifically, our contribution deals with integration of VC in different schemes for applications like digital watermarking and biometric authentication in the field of optics and photonics. We describe theoretical concepts and propose our infrastructure for the experiment. Finally, we will evaluate the learning outcome of the experiment, performed by the students. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
To successfully support private sector development in Africa by the use of trade and export promotion instruments, a comprehensive policy framework is crucial. Different institutional setups for development support show different levels of resilience and effectiveness in coping with the economic conditions they are exposed to. However, there is strong evidence that managing the interplay of three fundamental building blocks – public policy, focus areas, strategic objectives and critical success factors as well as institutions, is the key to crafting sustainable and responsive economies. Export plays a significant role in the national economy, and innovative and integrated government financing instruments have to successfully support the competitiveness of national companies in the global economy. Financing and supporting foreign trade with private businesses in Africa occupies a pivotal role, impacting from new product development and job creation in developed countries through economic growth and human development in African countries.
Nickel cobalt aluminum oxide (NCA) based lithium-ion battery electrodes exhibit a distinct asymmetry in discharge/charge behavior towards high bulk stoichiometry (low state of charge). We show that basic electrochemical relationships, that is, the Nernst equation and the Butler-Volmer equation, are able to reproduce this behavior when a two-step reaction mechanism is assumed. The two-step mechanism consists of (1) lithium-ion adsorption from the electrolyte onto the active material particle surface under electron transfer, and (2) intercalation of surface-adsorbed lithium atoms into the bulk material. The asymmetry of experimental half-cell data of an NCA electrode cycled at 0.1 C-rate can be quantitatively reproduced with this simple model. The model parameters show two alternative solutions, predicting either a saturated (highly-covered) or a depleted surface for high bulk lithiation.
Institute of Reliable Embedded Systems and Communication Electronics, Offenburg University of Applied Sciences, Germany has developed an automated testing environment, Automated Physical TestBeds (APTB), for analyzing the performance of wireless systems and its supporting protocols. Wireless physical networking nodes can connect to this APTB and the antenna output of this attaches with the RF waveguides. To model the RF environment this RF waveguides then establish wired connection among RF elements like splitters, attenuators and switches. In such kind of set up it’s well possible to vary the path characteristics by altering the attenuators and switches. The major advantage of using APTB is the possibility of isolated, well controlled, repeatable test environment in various conditions to run statistical analysis and even to execute regression tests. This paper provides an overview of the design and implementation of APTB, demonstrates its ability to automate test cases, and its efficiency.
BiCI users’ sensitivity to interaural phase differences for single- and multi-channel stimulation
(2016)
Bildnisverwertungsklauseln
(2016)
Kommentar zu "Intracortical microstimulation of human somatosensory cortex" von Sharlene N. Flesher et al., veröffentlicht in Science Translational Medicine, Vol. 8, No. 361, Seite 361ra141 (DOI: 10.1126/scitranslmed.aaf8083)
Bud type carbon nanohorns (CNHs) are composed of carbon and have a closed conical tip at one end protruding from an aggregate structure. By employing a simple oxidation process in CO2 atmosphere, it is possible to open the CNH tips which increases their specific surface area by four fold. These tip opened CNHs combine the microporous nature of activated carbons and the crystalline mesoporous character of carbon nanotubes. The results for the high pressure CO2 gas adsorption of tip opened CNHs are reported herein for the first time and are found to be superior to traditional CO2 adsorbents like zeolites. The modified CNHs are also found to be promising materials for lithium ion batteries and the performance is found to be on a par with carbon nanotubes and carbon nanofibers.
Aufgrund der zunehmenden Bedeutung von E-Prüfungen an Hochschulen und Universitäten werden Lösungen benötigt, die eine einfache, schnelle und sichere Nutzung von bestehenden Poolräumen für verschiedene Prüfungsszenarien ermöglichen. Das Projekt bwLehrpool hat in der Vergangenheit gezeigt, dass mit Hilfe von Virtualisierung eine große Anzahl an unterschiedlichen, individualisierten Lehrumgebungen flexibel und räumlich unabhängig verteilt werden kann. Im nächsten Schritt sollen nun Erweiterungen entwickelt werden, die diese Flexibilität auch für elektronische Prüfungen nutzbar macht. Dabei gilt es vor allem, die Vorteile, wie z.B. die Nutzung von Softwareunterstützung für realitätsnahe Aufgabenstellungen, mit der Notwendigkeit nach größtmöglicher Sicherheit und schneller Umrüstzeit der Infrastruktur in Einklang zu bringen. Um den aktuellen Entwicklungsstand zu testen, wurde im Wintersemester 2015/2016 an der Hochschule Offenburg eine E-Prüfung unter bwLehrpool durch über 140 Studierende durchgeführt. Die Ergebnisse zeigen, dass die Anforderungen bisher erfolgreich umgesetzt werden konnten, allerdings noch mehr manueller Aufwand nötig ist, als gewünscht. Der Ablauf soll in Zukunft weiter vereinfacht und verstetigt werden.
This paper presents an overview of the coding aspects of a GNSS receiver. Coding allows detection and correction of channel-induced errors at the receiver, here the focus is on the mitigation of threats from malicious interferences. Although the effects of interference at different stages of GNSS baseband processing has been deeply analyzed in the literature, little attention was devoted to its impact on the navigation message decoding stage. Theis paper provides an introduction to the various coding schemes employed by current GNSS signals, discussing their performance in the presence of noise in terms of block-error rate. Additionally, the benefits of soft-decoding schemes for navigation message decoding are highlighted when jamming interferences are present. The proposed scheme requires estimating the noise plus interference power, yielding to enhanced decoding performances under severe jamming conditions. Finally, cryptographic schemes as a means of providing anti-spoofing for geosecurity location-based services, and their potential vulnerability are discussed, with particular emphasis on the dependence on the dependence of the scheme on successful navigation message decoding
The ability to detect a signal masked by noise is improved in normal-hearing (NH) listeners when interaural phase differences (IPD) between the ear signals exist either in the masker or the signal. We determined the impact of different coding strategies in bilaterally implanted cochlear implant (BiCI) users with and without fine-structure coding (FSC) on masking level differences. First, binaural intelligibility level differences (BILD) were determined in NH listeners and BiCI users using their clinical speech processors. NH subjects (n=8) showed a significant mean BILD of 7.5 dB. In contrast, BiCI users (n=9) without FSC as well as with FSC revealed a barely significant mean BILD (0.4 dB respectively 0.6 dB). Second, IPD thresholds were measured in BiCI users using either their speech processors with FS4 or direct stimulation with FSC. With the latter approach, synchronized stimulation providing an interaural accuracy of stimulation timing of 1.67 µs was realized on pitch matched electrode pairs. The resulting individual IPD threshold was lower in most of the subjects with direct stimulation than with their speech processors. These outcomes indicate that some BiCI users can benefit from increased temporal precision of interaural FSC and adjusted interaural frequency-place mapping presumably resulting in improved BILD.
A new yield function for lamellar gray cast iron materials is proposed. The new model is able to describe the results of recently performed microstructure-based finite-element computations that resolve the three dimensional yield surface of three different gray cast irons. The yield function requires only the yield stress in tension and compression of the respective material as model parameters. Furthermore, the algorithmic formulation of the new model is assessed for numerical robustness and efficiency.
The number of impaired persons rises -- as a result of both regular degradation with age and psychological problems like burnout. Sheltered work organizations aim to reintegrate impaired persons into work environments and prepare them for the re-entry in the regular job market.
Both for elderly and for impaired persons it is crucial to quickly assess the abilities, to identify limits and potentials and thus find work processes suitable for their skill profile.
This work focuses on the analysis and comparison of software-tools that assess the abilities of persons with impairments. We describe two established generic tools (CANTAB, Cogstate), analyze a yet unknown specialized tool (Hamet) and present a new gamified tool (GATRAS).
Finally, we present a study with 20 participants with impairments, comparing the tools against a ground truth baseline generated by a real-world assembly task.
Der Kaiser ist ja nackt
(2016)
Components of rocket engines as actively cooled combustion chambers must withstand high pressure as well as severe and complex thermal transients. While the thermal transients result in temperature gradients and, thus, in constraint thermal strains, the pressure load induces mean stresses. To assess the mechanical behaviour of such components during design via finite-element calculations, constitutive models are necessary that describe the time- and temperature-dependent plasticity of the material appropriately.
Advanced models account for viscoplastic deformations including isotropic and kinematic hardening, recovery and ratcheting. However, the models contain a relatively large number of temperature-dependent material properties that must be determined on the basis of data of material tests. The determination of the properties is a non-trivial task because it is not clear which loading history must be applied in the tests for a certain material to obtain stable and robust (i.e. objective) material properties. Consequently, the determined properties are depending on the underlying loading history in the tests as well as on the experience and valuation of the person that determined the properties. This results in uncertainties during the assessment of the components that must be faced with conservative designs leading to negative consequences in terms of mass and costs.
It is the aim of this work funded by the European Space Agency ESA to derive a procedure to determine stable and robust material properties of an advanced viscoplastic constitutive model for aerospace materials. To this end, a special loading history is applied in isothermal material tests conducted with copper at different temperatures in the temperature range from 300 to 700 K. To determine the material properties and to assess stability and robustness methods for numerical optimization as well as analytical and statistical methods are used. The determined material properties are validated on the basis of results of thermomechanical material tests also conducted in the temperature range from 300 to 700 K.
The humanoid Sweaty was the finalist in this year’s robocup soccer championship(adult size). For the optimization of the gait and the stability, data concerning forces and torques in the ankle joints would be helpful. In the following paper the development of a six-axis force and torque sensor for the humanoid robot Sweaty is described. Since commercial sensors do not meet the demands for the sensors in Sweatys ankle joints, a new sensor was developed. As a measuring devices we used strain gauges and custom electronics based on an acam PS09. The geometry was analyzed with the FEM program ANSYS to get optimal dimensions for the measuring beams. In addition ANSYS was used to optimize the position for the strain gauges on the beam.