University of Applied Sciences Emden Leer
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509 research outputs found
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Complex Networks in Manufacturing and Logistics: A Retrospect
No full textThe methodology to model systems as graphs or networks already exists for a long time. The availability of information technology and computational power has led to a renaissance of the network modeling approach. Scientists have collected data and started to create huge models of complex networks from various domains. Manufacturing and logistics benefits from this development, because material flow systems are predetermined to be modeled as networks. This chapter revisits selected advances in network modeling and analysis in manufacturing and logistics that have been achieved in the last decade. It presents the basic modeling concept, the transition from static to dynamic and stochastic models, and a collection of examples how network models can be applied to contribute to solving problems in planning and control of logistic systems
Viscous damping exciting friction-induced vibration in pin-on-disk systems
No full textWhen engineers add damping to a vibrating system, they typically expect that this will result in a more stable system. However, a few rather complex examples are known that show the opposite trend: situations in which damping generates friction-induced vibration (damping paradox). In this study, we demonstrate that a simple but new surrogate model suffices to explain this effect, by analyzing a model with only one degree of freedom and a constant coefficient of friction. The instability of this model increases with an increase in the viscous damping coefficient perpendicular to the sliding direction. This shows that an unfavorable combination of geometric mounting of a friction-exposed mass together with ill-positioned damping can generate friction-induced vibration that would not appear without damping. The results are confirmed by finite element analysis and the corresponding complex eigenvalues. The excited mode shapes and frequencies correspond well with laboratory tests. This has consequences for applications such as the development of vehicle brake shims, which provide damping properties perpendicular to the sliding direction
Temperature-dependent damping of the tonewood spruce
No full textThe material wood is sustainable, resource- and energy-efficient and recyclable. Its low density which ranges between 0.5 and 0.8g/cm3 makes from it an important material in the transport sector, in which weight reduction is a key factor against the background of energy savings and the associated reduction in CO2 emissions. Wood can be regarded as a low-damping material, due to its molecular structure and its relatively high modulus of elasticity. This characteristic is well known to musical instrument makers. For musical instruments with a resonance body (e.g. piano, harpsichord, viola, cello, double bass, cymbal, harp, zither and certain organ pipes) spruce is the first choice of wood. Since the parameters time, temperature and moisture content influence the mechanical properties of wood, it is considered to be viscoelastic. Especially, the moisture content of the wood can significantly alter its sound quality and, thus, its damping behaviour. In order to study that moisture influence, the individual drying behaviour of nearly 130 years old spruce and new spruce wood was investigated by damping measurements as a function of the temperature. The material damping of new spruce wood was found to be generally higher than that of old spruce wood. Furthermore, former results showed that the damping of new wood is less sensitive to moisture content changes, which corresponds to a stable tone colour. Activation energies for damping mechanisms were calculated based on data from the Arrhenius plot of both woods. These results suggest that further or stronger damping mechanisms are active in new spruce wood
Comparing Voice Assistant Risks and Potential with Technology-Based Users: A Study from Germany and Spain
No full textCurrently, voice assistants (VAs) are trendy and highly available. The VA adoption rate of internet users differs among European countries and also in the global view. Due to speech intelligibility and privacy concerns, using VAs is challenging. Additionally, user experience (UX) assessment methods and VA improvement possibilities are still missing, but are urgently needed to overcome users' concerns and increase the adoption rate. Therefore, we conducted an intercultural study of technology-based users from Germany and Spain, expecting that higher improvement potential would outweigh concerns about VAs. We investigated VA use in terms of availability versus actual use, usage patterns, concerns, and improvement proposals. Comparing Germany and Spain, our findings show that nearly the same amount of intensive VA use is found in both technology-based user groups. Despite cultural differences, further results show very similar tendencies, e.g., frequency of use, privacy concerns, and demand for VA improvements
Global fintech entrepreneurship and its influencing factors: An evolutionary economic analysis
No full textFintech entrepreneurship has already influenced financial markets and their players worldwide in a disruptive, but also a risky way (Thakor, 2020; Zeranski & Sancak, 2020). In this context, it seems worthwhile to analyze which factors drive the design and development of global fintech entrepreneurship. Thus, the paper takes fintech-related research a step further by exploring the drivers of fintech evolution in different countries and continents that display different levels of fintech activity. For this purpose, first economic, technological, legal, and cultural factors influencing the development of fintech entrepreneurship are examined from an evolutionary point of view, and second, a generalized linear mixed model is used in order to evaluate the statistical relevance of these factors on fintech entrepreneurship more comprehensively. The analyzed data period from 2000 to 2017 also makes it possible to assess the influence of the dot.com bubble and the financial crisis on fintech entrepreneurship. The results of the empirical analysis suggest that the gross domestic product (GDP), regulatory burden, government tech procurement and the degree of individualism are important drivers of fintech startup activity. These findings help gauge the present and future market position of fintechs, leading to implications for entrepreneurs, competitors, and regulators alike
A 70-Year Industrial Electronics Society Evolution Through Industrial Revolutions: The Rise and Flourishing of Information and Communication Technologies
No full textThe Industrial Revolution, which originally involved the change from an agrarian and handicraft economy to a market dominated by factory mechanization during the early 18th century, has profoundly shaped the world. It has progressed through four disruptive phases: Industry 1.0 through Industry 4.0. Industry 1.0 encompassed early automation, while Industry 2.0 began at the end of the 19th century, when enormous technological advances were made, such as mass production, electrification, and new modes of transportation. Industry 3.0 began during the 1970s, a decade that gave rise to the electronics, telecommunications, and computing that enable full automation and robotics. Industry 4.0 kicked off at the dawn of the third millennium, marked by the ubiquitous use of Internet technologies, which have radically transformed how people, society, and industry interact
Perspectives for a Wind Assisted Ship Propulsion
No full textFor three different wind propulsion technologies, the energy saving potential of sea going cargo vessels are discussed: a kite, a Flettner rotor and a Dynarig-sail. The energy saving potential can be increased significantly if the route can be optimized when using a wind assisted ship propulsion. The increase of travelling time due to a route adoption is within the frame of the commonly accepted uncertainty in supply chains and can be limited or adjusted in the route optimization software as a parameter. The calculated saving potential depends on several parameters: the considered wind propulsion system, the route, the kind of ship (bulker, multipurpose carrier, tanker), as well as the ship speed and the weather. The cost-effectiveness of the installation of a wind propulsion system strongly depends on the fuel price, the ship speed and the international policy concerning the ship emissions
Transmitting Surface Plasmon Polaritons across Nanometer-Sized Gaps by Optical near-Field Coupling
No full textMetallic nanostructures can transport electromagnetic fields in the form of surface plasmon polariton (SPP) excitations, focus them into nanometric spots, and transfer them to nearby nanostructures by near-field coupling. This provides a basic functionality for designing new plasmonic devices that can greatly enhance light–matter coupling and facilitate ultrafast and efficient all-optical switching on the nanoscale. Here, we study a prototypical device geometry, a bow-tie antenna equipped with curved line gratings, for the efficient coupling of light into and across the antenna nanogap. We experimentally demonstrate the spectrally broadband launching and propagation of SPP waves over more than 10 μm on one arm of the antenna, their focusing into and transmission across the gap being studied by the plasmon outcoupling on the other arm. A substantial increase in the coupling efficiency for antennas with gap widths below 20 nm proves that the optical near-field coupling between the two antenna arms dominates the gap transmission. We find overall transmission efficiencies for nanofocusing, gap transmission, and plasmon outcoupling of up to 4%. A finite-difference time-domain simulation supports our experimental findings. This makes such bow-tie couplers an interesting platform for sensitively probing near-field coupling to single quantum emitters and for the ultrafast switching of light by light on the nanoscale
Ermittlung relevanter UX-Faktoren je Produktkategorie für den UEQ+
No full textDie User Experience ist ein relevanter Aspekt für eine erfolgreiche Produktentwicklung. Ein geeignetes Instrument für die quantitative Messung der User Experience sind Fragebögen wie der UEQ+. Dieser erlaubt es, mithilfe der zur Verfügung gestellten Skalen produktindividuelle Fragebögen zu erstellen. Es ist jedoch wahrnehmbar, dass manche UX-Faktoren für konkrete Produktkategorien relevanter sind als für andere. Welche Faktoren in welchem konkreten Anwendungsfall wichtig sind, wird in dieser Arbeit gezeigt. Dafür wurden zwei Studien aus 2016 und 2017 ausgewertet. Durch eine Korrelationsanalyse sowie t-Tests konnte nachgewiesen werden, dass die Ergebnisse beider Studien robust genug sind, sodass sie zu einem Gesamtdatensatz zusammengefasst werden konnten. Aus diesem Datensatz konnte eine globale Relevanzgrenze ermittelt werden, bei deren Überschreitung ein Faktor als relevant für ein Produkt angesehen werden kann. Das Ergebnis zeigt, dass die vermuteten Wichtigkeitsunterschiede nachgewiesen werden konnten. Dies sollte in der Produktentwicklung berücksichtigt werden, u. a. um die Stärken und Schwächen des Produkts zu identifizieren
How to create short forms of UEQ+ based questionnaires?
No full textThe UEQ+ is a modular framework that can be used to set up UX questionnaires that fit to a research question. The UEQ+ consists of a set of UX scales that can be combined to form a concrete questionnaire. Thus, the product owner or UX researcher can define which aspects of UX are important for his or her project and should thus be measured in the questionnaire. A UEQ+ scale consists of 4 items that measure the UX aspect represented by the scale and an additional item that measures how important this UX aspect is for the overall UX impression. Some situations require that a UX questionnaire is extremely short and for such situations the standard scale format may be too time consuming. We describe how short forms of the UEQ+ can be built. The impact of shortening the scales on the results is investigated in several studies