Refine
Year of publication
Document Type
- Conference Proceeding (308)
- Article (288)
- Master's Thesis (113)
- Part of a Book (53)
- Book (19)
- Doctoral Thesis (9)
- Report (6)
- Preprint (5)
- Working Paper (4)
- Other (3)
- Periodical (3)
- Part of Periodical (3)
- Habilitation (1)
Institute
- Forschungszentrum Mikrotechnik (247)
- Forschungszentrum Business Informatics (149)
- Technik | Engineering & Technology (127)
- Department of Computer Science (Ende 2021 aufgelöst; Integration in die übergeordnete OE Technik) (112)
- Wirtschaft (106)
- Forschungszentrum Energie (79)
- Didaktik (mit 31.03.2021 aufgelöst; Integration ins TELL Center) (37)
- Forschungszentrum Human Centred Technologies (35)
- Soziales & Gesundheit (34)
- Josef Ressel Zentrum für Materialbearbeitung (27)
Language
- English (815) (remove)
Keywords
- Laser ablation (11)
- Y-branch splitter (11)
- arrayed waveguide gratings (11)
- photonics (8)
- Evolution strategy (7)
- Demand side management (6)
- Optimization (6)
- integrated optics (6)
- AWG (5)
- Arrayed waveguide gratings (5)
A step change is needed in the deployment of renewable energy if the triple challenge of ensuring climate change mitigation, energy security, and energy affordability is to be met. Yet, social acceptance of infrastructure projects and policies remains a key concern. While there has been decades of fruitful research on the social acceptance of wind energy and other renewables, much of the extant research is cross-sectional in nature, failing to capture the important dynamic processes that can make or break renewable energy projects. This paper introduces a Special Issue of Energy Policy which focuses on the neglected topic of the dynamics of social acceptance of renewable energy, drawing on contributions made at an international research conference held in St. Gallen (Switzerland) in June 2022. In addition to introducing these papers and drawing out common themes, we also seek to offer some conceptual clarity on the issue of dynamics in social acceptance, taking into account the influence of time, power, and scale in shaping decision-making processes. We conclude by highlighting a number of avenues of potential future research.
X-ray microtomography is a nondestructive, three-dimensional inspection technique applied across a vast range of fields and disciplines, ranging from research to industrial, encompassing engineering, biology, and medical research. Phasecontrast imaging extends the domain of application of x-ray microtomography to classes of samples that exhibit weak attenuation, thus appearing with poor contrast in standard x-ray imaging. Notable examples are low-atomic-number materials, like carbon-fiber composites, soft matter, and biological soft tissues.We report on a compact and cost-effective system for x-ray phase-contrast microtomography. The system features high sensitivity to phase gradients and high resolution, requires a low-power sealed x-ray tube, a single optical element, and fits in a small footprint. It is compatible with standard x-ray detector technologies: in our experiments, we have observed that single-photon counting offered higher angular sensitivity, whereas flat panels provided a larger field of view. The system is benchmarked against knownmaterial phantoms, and its potential for soft-tissue three-dimensional imaging is demonstrated on small-animal organs: a piglet esophagus and a rat heart.We believe that the simplicity of the setupwe are proposing, combined with its robustness and sensitivity, will facilitate accessing quantitative x-ray phase-contrast microtomography as a research tool across disciplines, including tissue engineering, materials science, and nondestructive testing in general.
Parametric anti-resonance is a phenomenon that occurs in systems with at least two degrees of freedom; this can be achieved by periodically exciting some parameters of the system. The effect of this properly tuned periodicity is to increase the dissipation in the system, which leads to a raising in the effective damping of vibrations. This contribution presents the design of an open-loop control to reduce the settling time using the anti-resonance concept. The control signal consists of a quasi-periodic signal capable of transferring the system’s oscillations from one mode to another mode of the system. The general averaging technique is used to characterize the dynamics, particularly the so-called slow dynamics of motion. With this analysis, the control signal is designed for the potential application of a microelectromechanical sensor arrangement; for this specific example, up to 96.8% reduction of settling time is achieved.
In this work, parametric excitation is introduced in a fully balanced flexible rotor mounted on two identical active gas foil bearings. The active gas foil bearings change the top foil shape harmonically with a specific amplitude and frequency. The deformable foil shape is approximated by an analytical function, while the gas pressure distribution is evaluated by the numerical solution of the Reynolds equation for compressible flow. The harmonic variation of the foil shape generates a respective variation in the bearings’ stiffness and damping properties and the system experiences parametric resonances and antiresonances in specific excitation frequencies. The nonlinear gas bearing forces generate bifurcations in the solutions of the system at certain rotating speeds and excitation frequencies; period doubling and Neimark-Sacker bifurcations are noticed in the examined system, and their progress is evaluated as the two bifurcation parameters (rotating speed and parametric excitation frequency) are changed, though a codimension-2 numerical continuation of limit cycles. It is found that at specific range of excitation frequency there are parametric anti-resonances and the bifurcations collide and vanish. Therefore, a bifurcation-free operating range is established and the system can operate stable at a wide speed range.
Digitalization is changing business models and operational processes. At the same time, improved data availability and powerful analytical methods are influencing controlling and increasingly require the use of statistical and information technology skills and knowledge. Using a case study from marketing controlling, the article shows the use of business analytics methods and addresses the tasks of controlling in the digital age.
By a simple femtosecond laser process, we fabricated metal-oxide/gold composite films for electrical and optical gas sensors. We designed a dripple wavelength AWG-spectrometer, matched to the plasma absorption wavelength region of the composite films. H2/CO absorptions fit well with the AWG design for multi gas detection sensor arrays
Pooled data from published reports on infants with clinically diagnosed vitamin B12 (B12) deficiency were analyzed with the purpose of describing the presentation, diagnostic approaches, and risk factors for the condition to inform prevention strategies. An electronic (PubMed database) and manual literature search following the PRISMA approach was conducted (preregistration with the Open Science Framework, accessed on 15 February 2023). Data were described and analyzed using correlation analyses, Chi-square tests, ANOVAs, and regression analyses, and 102 publications (292 cases) were analyzed. The mean age at first symptoms (anemia, various neurological symptoms) was four months; the mean time to diagnosis was 2.6 months. Maternal B12 at diagnosis, exclusive breastfeeding, and a maternal diet low in B12 predicted infant B12, methylmalonic acid, and total homocysteine. Infant B12 deficiency is still not easily diagnosed. Methylmalonic acid and total homocysteine are useful diagnostic parameters in addition to B12 levels. Since maternal B12 status predicts infant B12 status, it would probably be advantageous to target women in early pregnancy or even preconceptionally to prevent infant B12 deficiency, rather than to rely on newborn screening that often does not reliably identify high-risk children.
Grey Box models provide an important approach for control analysis in the Heating, Ventilation and Air Conditioning (HVAC) sector. Grey Box models consist of physical models where parameters are estimated from data. Due to the vast amount of component models that can be found in literature, the question arises, which component models perform best on a given system or dataset? This question is investigated systematically using a test case system with real operational data. The test case system consists of a HVAC system containing an energy recovery unit (ER), a heating coil (HC) and a cooling coil (CC). For each component, several suitable model variants from the literature are adapted appropriately and implemented. Four model variants are implemented for the ER and five model variants each for the HC and CC. Further, three global optimization algorithms and four local optimization algorithms to solve the nonlinear least squares system identification are implemented, leading to a total of 700 combinations. The comparison of all variants shows that the global optimization algorithms do not provide significantly better solutions. Their runtimes are significantly higher. Analysis of the models shows a dependency of the model accuracy on the number of total parameters.
Purpose – The purpose of this study is to explore the exogenous and endogenous drivers of the high-growth of Unicorn start-ups along their life cycle, with a particular focus on Unicorns in the fintech industry.
Design/methodology/approach – The study employs an explorative longitudinal analysis with a matched pair of two cases of Unicorns start-ups with similar antecedent features to understand holistically drivers over the longer term.
Findings – High-growth patterns over the longer term are the result of a combined industry- and company-life cycle perspective. Drivers and growth patterns vary significantly according to the time of entry in the industry and
its development status. The findings are systematised within a set of propositions to be tested in future research.
Research limitations/implications – The limitations lie in empirical evidence, as the analysis is limited to one matched-pair. The revealed Unicorns’ drivers for long-term growth might encourage future research to further investigate these drivers on a larger scale.
Practical implications – The study offers practical recommendations for start-ups with high-growth ambitions and advice to policy makers regarding the development of tailor-made support programs.
Originality/value – The study significantly extends extant work on growth and high-growth by examining endogenous and exogenous triggers over time and by linking the Unicorn-life cycle to the industry life cycle, an approach which has, to the best of the authors’ knowledge, not yet been applied.
International Entrepreneurship explains the opportunities and challenges facing internationalizing entrepreneurial ventures. The book inlcudes a thorough discussion of fundamentals as well as contemporary research findings. Numerous cases, featuring diverse contexts, illustrate theory and help classroom use.
The main aims of this work are the validation of the developed process of gluing a single-mode optical fiber array with a photonic chip and the selection of a more suitable adhesive from the two adhesives being compared. An active alignment system was used for adjusting the two optical fiber arrays to a photonics chip. The gluing was done by two compared UV curable adhesives applied in the optical path. The insertion losses of glued coupling were measured and investigated at two discrete wavelengths 1310 nm and 1550 nm during temperature testing in the climatic chamber according to Telcordia GR_1209_Corei04 [3]. The measurement, investigation, and comparison of insertion losses of the glued coupling at the spectral band from 1530 nm to 1570 nm were done immediately after gluing process and after three temperature cycles in the climatic chamber with one month delay.
In 2021, a prominent Austria dairy producer suffered from an IT attack and was completely paralysed. Without clearly defined mitigation measures in place, major disruptions were caused alongside the whole supply chain, including logistics service providers, governmental food safety bodies, as well as retailers (i.e., supermarkets and convenience stores). In this paper, we ask the question how digitisation and digital transformation impact IT security, especially when considering the complex company ecosystems of food production and food supply chains in Austria. The problem statement stems from a gap in knowledge of key differences in approaches towards IT security, resilience, risk management and especially business interfaces between food suppliers, supermarkets, distributors, logistics and other service providers. In order to answer related research questions, firstly, the authors conduct literature research, and highlight common guidelines and standardisation as well as look at state-based recommendations for critical infrastructure. In a second step, the paper describes a quantitative and qualitative survey with Austrian food companies (producers and retailers) which is described in detail in the paper. A description of recommended measures for the industry, further steps, as well as an outlook conclude the paper.
Background: Cardiovascular disease is the major cause of death worldwide. Although knowledge regarding diagnosing and treating cardiovascular disease has increased dramatically, secondary prevention remains insufficiently implemented due to failure among affected individuals to adhere to guideline recommendations. This has continued to lead to high morbidity and mortality rates. Involving patients in their healthcare and facilitating their active roles in their chronic disease management is an opportunity to meet the needs of the increasing number of cardio-vascular patients. However, simple recall of advice regarding a more preventive lifestyle does not affect sustainable behavioral lifestyle changes. We investigate the effect of plaque visualization combined with low-threshold daily lifestyle tasks using the smartphone app PreventiPlaque to evaluate change in cardiovascular risk profile. Methods: and study design: This randomized, controlled clinical trial includes 240 participants with ultrasound evidence of atherosclerotic plaque in one or both carotid arteries, defined as focal thickening of the vessel wall measuring 50% more than the regular vessel wall. A criterion for participation is access to a smartphone suitable for app usage. The participants are randomly assigned to an intervention or a control group. While both groups receive the standard of care, the intervention group has additional access to the PreventiPlaque app during the 12-month follow-up. The app includes daily tasks that promote a healthier lifestyle in the areas of smoking cessation, medication adherence, physical activity, and diet. The impact of plaque visualization and app use on the change in cardiovascular risk profile is assessed by SCORE2. Feasibility and effectiveness of the PreventiPlaque app are evaluated using standardized and validated measures for patient feedback.
The production of liquid-gas mixtures with desired properties still places high demands on process technology and is usually realized in bubble columns. The physical calculation models used have individual dimensionless factors which, depending on the application, are only valid for small ranges consisting of flow velocity, nozzle geometry and test setup. An iterative but time-consuming design of such dispersion processes is used in industry for producing a liquid-gas mixture according to desired requirements. In the present investigation, we accelerate the necessary design loops by setting up a physical model, which consists of several subsystems that are enriched by dedicated experiments to realize liquid-gas dispersions with low volume fraction and small air bubble diameters in oil. Our approach allows the extraction of individual dimensionless factors from maps of the introduced subsystems. These maps allow for targeted corrective measures of a production process for keeping the quality. The calculation-based approach avoids the need for performing iterative design loops. Overall, this approach supports the controlled generation of liquid-gas mixtures.
Creating a schedule to perform certain actions in a realworld environment typically involves multiple types of uncertainties. To create a plan which is robust towards uncertainties, it must stay flexible while attempting to be reliable and as close to optimal as possible. A plan is reliable if an adjustment to accommodate for a new requirement causes only a few disruptions. The system needs to be able to adapt to the schedule if unforeseen circumstances make planned actions impossible, or if an unlikely event would enable the system to follow a better path. To handle uncertainties, the used methods need to be dynamic and adaptive. The planning algorithms must be able to re-schedule planned actions and need to adapt the previously created plan to accommodate new requirements without causing critical disruptions to other required actions.
The usage of data gathered for Industry 4.0 and smart factory scenarios continues to be a problem for companies of all sizes. This is often the case because they aim to start with complicated and time-intensive Machine Learning scenarios. This work evaluates the Process Capability Analysis (PCA) as a pragmatic, easy and quick way of leveraging the gathered machine data from the production process. The area of application considered is injection molding. After describing all the required domain knowledge, the paper presents an approach for a continuous analysis of all parts produced. Applying PCA results in multiple key performance indicators that allow for fast and comprehensible process monitoring. The corresponding visualizations provide the quality department with a tool to efficiently choose where and when quality checks need to be performed. The presented case study indicates the benefit of analyzing whole process data instead of considering only selected production samples. The use of machine data enables additional insights to be drawn about process stability and the associated product quality.