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In this thesis the effect of dc voltage bias on the equivalent series resistance (ESR) of capacitors and especially ferroelectric dielectric ceramic capacitors (FDCC) is analysed. Further the influence of the dc biased ESR on the losses of capacitors is investigated. Also piezoelectric resonances (PR) occurring in FDCCs with applied dc bias and their influence on the losses are analysed.
Therefore a measurement circuit to measure the impedance and thus the ESR of capacitors in combination with a vector network analyser (VNA) is developed. Using the developed circuit the ESR of capacitors of different technologies is measured and their behaviour with dc bias is evaluated. The losses of an FDCC are measured in a power electronic (PE) circuit with a developed calorimetric measurement system (CMS). The influence of the PR is investigated by tuning the switching frequency of the PE system and thus the frequency of the capacitor current exactly into the PR. The measured losses are then compared to a calculation based on the capacitor current harmonics and the respective ESR.
The measurements show an increase of the ESR with dc bias for all measured FDCCs. The loss measurements show a significant increase of the losses in an FDCC if the current frequency matches the PR frequency. Consequently a decrease of the PE system's efficiency is measured. The loss calculations do not exactly match the measurements but there is a systematic deviation of the same order for all measurements.
The implementation of direct-to-consumer (D2C) business models has become more important for companies trying to develop a competitive edge and improve consumer engagement in today's rapidly expanding e-commerce market. This master's thesis investigates the important success elements and problems of deploying D2C models in the e-commerce business. The research question focuses on identifying the factors that contribute to the successful transition to D2C models and the obstacles businesses encounter along the way. Through qualitative research using the Eisenhardt method and in-depth case studies with industry experts, this study provides valuable insights into key success factors for direct-to-consumer (D2C) business models in e-commerce.The findings highlight that businesses that effectively implement D2C models utilize key success factors such as a clear value proposition, customer engagement and relationship build- ing, seamless online experiences, targeted marketing and digital advertising, brand identity and storytelling, and flexibility and adaptability. However, they also face challenges related to operational adjustments, marketing and branding investments, competition, and market saturation. Based on these research outcomes, this thesis provides recommendations for businesses seeking to switch to or implement D2C models in e-commerce. These recommendations emphasize embracing a customer-centric mindset, developing digital capabilities, foster- ing strong leadership commitment, leveraging data and analytics, establishing direct customer relationships, optimizing operational processes, building brand trust and credibility, and allocating resources wisely. This master's thesis provides a comprehensive analysis of the key success factors and challenges associated with the transition to or implementation of D2C business models in the e-commerce industry. It provides advice to help companies successfully transition to D2C models.
The master thesis concentrates on two different cases to generate energy from MSW. In the first case, the MSW is incinerated in an incineration plant. This approach represents the present situation in the waste treatment in large parts of the UK.
In the second case, the OFMSW is separated in a treatment facility and used in a fermentation plant. The remaining waste is again used as a feedstock in an incineration plant. The difference in the net energy yield between these two cases is investigated in this thesis.
To calculate the difference in the energy yield of case 1 and case 2, a research of the existing literature about comparisons of incineration and fermentation plants and their results are reflected and data about the MSW in the UK is collected. With the input of the literature and the researched data, a model is built which compares the two different cases of waste treatment. The results of the comparisons are then examined by varying different parameters. This step is repeated by using different input parameters. Afterwards, the results are compared and analysed.
In the next part of the thesis, an economic analysis of the incineration and fermentation combined technology plant is made. In this analysis, the investment costs, the annual profits and the annual costs of an additional fermentation plant are discussed and calculated. The result of the analysis is displayed as an amortization time calculation. The results are then analysed by varying the parameters in a sensitivity analysis.
Finally, the research question is answered and a forecast for possible plant designs with an incineration and a fermentation plant in combination are discussed.
An implementation approach of the gap navigation tree using the TurtleBot 3 Burger and ROS Kinetic
(2020)
The creation of a spatial model of the environment is an important task to allow the planning of routes through the environment. Depending on the number of sensor inputs different ways of creating a spatial environment model are possible. This thesis introduces an implementation approach of the Gap Navigation Tree which is aimed for usage with robots that have a limited amount of sensors. The Gap Navigation Tree is a tree structure based on depth discontinuities constructed from the data of a laser scanner. Using the simulated TurtleBot 3 Burger and ROS kinetic a framework is created that implements the theory of the Gap Navigation Tree. The framework is structured in a way that allows using different robots with different sensor types by separating the detection of depth discontinuities from the building and updating of the Gap Navigation Tree.
Organic acidurias (OAs), urea-cycle disorders (UCDs), and maple syrup urine disease (MSUD) belong to the category of intoxication-type inborn errors of metabolism (IT-IEM). Liver transplantation (LTx) is increasingly utilized in IT-IEM. However, its impact has been mainly focused on clinical outcome measures and rarely on health-related quality of life (HRQoL). Aim of the study was to investigate the impact of LTx on HrQoL in IT-IEMs. This single center prospective study involved 32 patients (15 OA, 11 UCD, 6 MSUD; median age at LTx 3.0 years, range 0.8–26.0). HRQoL was assessed pre/post transplantation by PedsQL-General Module 4.0 and by MetabQoL 1.0, a specifically designed tool for IT-IEM. PedsQL highlighted significant post-LTx improvements in total and physical functioning in both patients' and parents' scores. According to age at transplantation (≤3 vs. >3 years), younger patients showed higher post-LTx scores on Physical (p = 0.03), Social (p < 0.001), and Total (p =0.007) functioning. MetabQoL confirmed significant post-LTx changes in Total and Physical functioning in both patients and parents scores (p ≤ 0.009). Differently from PedsQL, MetabQoL Mental (patients p = 0.013, parents p = 0.03) and Social scores (patients p = 0.02, parents p = 0.012) were significantly higher post-LTx. Significant improvements (p = 0.001–0.04) were also detected both in self- and proxy-reports for almost all MetabQoL subscales. This study shows the importance of assessing the impact of transplantation on HrQoL, a meaningful outcome reflecting patients' wellbeing. LTx is associated with significant improvements of HrQol in both self- and parentreports. The comparison between PedsQL-GM and MetabQoL highlighted that MetabQoL demonstrated higher sensitivity in the assessment of diseasespecific domains than the generic PedsQL tool.
Recent years have been commanded by a cascade of unpredictable incidents, that have redefined new standards in our private, but also in our professional life. Events like the financial crisis, the COVID-19 pandemic, the energy crisis in Europe, resource scarcity and so forth have caused instability, forcing companies towards flexibility, constantly adapting their operative structures according to the needs of the moment. The effective adaptation to this environment is the key for reacting the dynamism of the market, and for guaranteeing future success. However, the introduction of these crucial changes on a stable company organisation is challenging. Furthermore, due to digitalisation, boundaries between countries have been removed, and the daily cooperation with co-workers and customers all around the globe became the new standard. The establishment of a good corporate culture where diverse people can work in harmony and, is a difficulty that comes ahead.
This master thesis developed from a professional perspective. The topics of change management and corporate culture where combined, and the relationship between these two concepts was studied. This master thesis aims utilising corporate culture as an instrument in managements favour, to implement strategical changes easily and successfully in a more efficient way. The relation between corporate culture and the resistance to change, focusing on the initiation of the change process, was the main area of study. Research questions and hypothesis, formulated with a solid theoretical background, are to be answered based firstly on literature, and secondly on the results of empirical quantitative re-search. To conclude, a set of recommendations for corporates were suggested with the intention of guiding companies how to use corporate culture as an instrument for change management.
We present a new concept of 3D polymer-based 1 × 4 beam splitter for wavelength splitting around 1550 nm. The beam splitter consists of IP-Dip polymer as a core and polydimethylsiloxane (PDMS) Sylgard 184 as a cladding. The splitter was designed and simulated with two different photonics tools and the results show high splitting ratio for single-mode and multi-mode operation with low losses. Based on the simulations, a 3D beam splitter was designed and realized using direct laser writing (DLW) process with adaptation to coupling to standard single-mode fiber. With respect to the technological limits, the multi-mode splitter having core of (4 × 4) μm 2 was designed and fabricated together with supporting stable mechanical construction. Splitting properties were investigated by intensity monitoring of splitter outputs using optical microscopy and near-field scanning optical microscopy. In the development phase, the optical performance of fabricated beam splitter was examined by splitting of short visible wavelengths using red light emitting diode. Finally, the splitting of 1550 nm laser light was studied in detail by near-field measurements and compared with the simulated results. The nearly single-mode operation was observed and the shape of propagating mode and mode field diameter was well recognized.
The phenomenon of the increase of numerous widespread and common diseases, ranging from simple dental problems to obesity, high blood pressure or diabetes, is a concern which can be observed in various aspects of the entire world. Reasons for this is a combination of an unhealthy diet and insufficient physical activity. Consequently, governments across the globe are seeing the need to change consumer behaviour by introducing plain packaging regulations. From an entrepreneurial point of view, this would result in financial losses as well as various limitations in product design, branding and differentiation. Therefore, an empirical study with 232 respondents was conducted, which revealed that the use of images on packaging activates emotions in customers within a few seconds. This master thesis examines possible correlations and differences between the importance of emotionally loaded product packaging and consumer behaviour at the point of sale. The persuasive effect of images on purchase decisions is based on personal consumer experiences and validated processing in the brain which trigger specific emotions. Modern companies are able to communicate company values through emotions by using images correctly. The results of the conducted survey enable Diezano to successfully implement the communication strategy in the event of the introduction of plain packaging regulations. By using mountain graphics, Diezano conveys values such as home, regional, refreshment, tasty, memories of childhood and nostalgia, which the brand aims to convey to the market. Based on the result of this master thesis, it is concluded that the picture superiority effect is mostly underestimated, yet it is an indispensable medium for emotional differentiation and thus a company’s success.
The e-commerce market has been growing for years and this trend seems to be continuing. Online stores for clothing are very successful. It seems that hardly any company can afford not to have a digital presence. This goes hand in hand with the fact that the range of products on offer to customers is getting bigger and bigger. But it's not just the range that's getting bigger, it's also the effort customers have to make to find the right product. For this reason, many successful online stores are already relying on AI. In doing so, companies are creating opportunities for customers that an employee could hardly manage. Implemented on the website, AI can check inventory, update it in real time, predict trends and evaluate customer or user data and make suitable recommendations. This is important for the customer because with the huge choice available, for one thing, personalization is increasingly important and being presented with a relevant selection. A central question is whether the recommendations are trustworthy and whether they can be equated with a real salesperson advising the customer. After all, trust is relevant in longterm customer relationships in that it leads to loyalty and satisfaction, which in turn increases the intention to repurchase. The recommendation tools mentioned are also of particular interest for another reason. On the one hand, they help customers to get a relevant selection of the offer and thus to get faster to the desired one. On the other hand, they are relevant for companies not only because of customer satisfaction, but also because of the chance to reduce returns. The large online stores for clothing offer their customers very generous opportunities to return the goods free of charge. In doing so, the companies have responded to customer wishes, because hardly anything is more important to them when it comes to online shopping: free returns. In this way, customers have minimized the risk of having to keep goods that do not fit or please them. This thesis examines whether recommendation tools can help customers to better assess the sizes and properties of clothing, so that they receive more suitable clothing and do not even feel the need to order several sizes of the same item of clothing. It can therefore be assumed that trust in the recommendations of the AI tools reduces uncertainty, which in turn should reduce the intention to return goods. Another assumption to be tested is that of the perceived usefulness of the recommendation tools. As a prerequisite to get an assessment of these assumptions is the usage of the tools. Therefore, a survey was initiated in the DACH region to assess the extent to which usage influences the factors mentioned. It was found by means of a regression analysis that the frequency of online purchases, mediated by perceived usefulness, explains the influence on trust.
We present design and simulation of 16-channel, 100-GHz silicon nitride based AWG using BeamPROP simulation engine of RSoft photonic tool. The AWG was designed for TM-polarized light with central wavelength of 850 nm. The input design parameters were calculated applying AWG-Parameters tool. For this purpose, we created a ridge waveguide structure, used in the design of the AWG layout, and performed FEM simulation. The output of the BPM simulation of AWG structure are the transmission characteristics, which was used to calculate transmission parameters defining optical properties of simulated AWG. The achieved simulation results are in a good agreement with the design.
Observing the ratios of the rail usage in terms of passenger travelled per km and per capita, we see that there are huge differences between countries, so some railway systems are performing better in catching passengers than others. By analysing the factors that make the railways attractive for users, and setting standard values for these factors, we can analyse how well a system is performing. This paper has investigated those factors and developed an assessment tool that will inform about the required improvements, so in a later stage specific strategies can be developed to increase the performance in order to attract more passengers. Spain will be used as case study, since the country has specially low passenger rail usage compared to other countries even though the large investments in high speed lines the country undertook in the last decades.
Noisy optimization. A theoretical strategy comparison of ES, EGS, SPSA & IF on the noisy sphere
(2011)
Stress testing is part of today’s bank risk management and often required by the governing regulatory authority. Performing such a stress test with stress scenarios derived from a distribution, instead of pre-defined expert scenarios, results in a systematic approach in which new severe scenarios can be discovered. The required scenario distribution is obtained from historical time series via a Vector-Autoregressive time series model. The worst-case search, i.e. finding the scenario yielding the most severe situation for the bank, can be stated as an optimization problem. The problem itself is a constrained optimization problem in a high-dimensional search space. The constraints are the box constraints on the scenario variables and the plausibility of a scenario.
The latter is expressed by an elliptic constraint. As the evaluation of the stress scenarios is performed with a simulation tool, the optimization problem can be seen as black-box optimization problem. Evolution Strategy, a well-known optimizer for black-box problems, is applied here. The necessary adaptations to the algorithm are explained and a set of different algorithm design choices are investigated. It is shown that a simple box constraint handling method, i.e. setting variables which violate a box constraint to the respective boundary of the feasible domain, in combination with a repair of implausible scenarios provides good results.
In this work, the simulation possibilities of transient magnetic fields are investigated. For this purpose, an experimental setup is established to compare the simulation results with actual measurement data.
The experimental set-up consists of two coils, which are placed on two U-shaped iron cores. These cores are then brought together to form two air-gaps. These two gaps are used for measurement and the optional insertion of samples. The simulations are carried out with the finite element method (FEM) program ANSYS Maxwell 19R3.
In the first experiments, static simulations and measurements are compared to verify the validity of the available material data and the simulation techniques, especially the symmetry considerations, excitations of the coils, and boundary conditions. The static simulations show two main sources of uncertainty. The B-H curve of the core material used in the simulations and the air-gap distance uncertainty.
After validating the simulations with the static measurements, transient experiments are performed. In these experiments, the qualitative agreement of the simulation and measurement, as well as the characteristic rise times are compared. The experiments show a decisive influence of the considered loss mechanisms on the agreement of the simulation results with the measurements. Therefore, several simulations with different loss mechanisms are performed.
Finally, also the simulation capability including a material sample in the upper gap is investigated. Therefore, the conformity of the relative change of the measurement and the simulation is compared.
In the experiments a good simulation capability within a 5% error bar is seen. The main difficulty of this work represents the uncertainty due to the available material data. It is assumed, that with more accurate material data the error can be reduced significantly.
Mobility choices - an instrument for precise automatized travel behavior detection & analysis
(2021)
We have demonstrated micromachining of bulk 3C silicon carbide (3C- SiC) wafers by employing 1028nm wavelength femtosecond laser pulses of energy less than 10 nJ directly from a femtosecond laser oscillator, thus eliminating the need for an amplified system and increasing the micromachining speed by more than four orders of magnitude.
Lack of transparency and traceability of products and their raw materials means that most products can only be thrown away or not properly recycled due to a lack of relevant data. This conflicts with the circular economy principles, which are demanded by several initiatives, including the European Union. The aim of this master thesis is to analyze this conflict and to propose a technical solution based on Distributed Ledger Technology that enables transparency and traceability of products and their materials. Therefore, the thesis addresses two central research questions: 1. How can traceability and transparency be enabled by integrating a DLT solution? 2. How would a prototype with the integration of smart contracts and DLT look like? To answer these questions, a blockchain solution is implemented using Hyperledger Fabric. The solution uses the immutability and decentralized nature of DLT to record and track the movement of products and their materials throughout their life cycle in the Circular Economy. Furthermore, with private data collections, confidentiality, and privacy are granted while ensuring transparency. The thesis contributes to the Circular Economy field by exploring the principles, models, and challenges of the Circular Economy and the circularity goals of a Digital Product Passport to develop a suitable technical solution. The chosen blockchain framework, Hyperledger Fabric, is presented, and its key components and features are highlighted. The thesis also delves into the design decisions and considerations behind the Digital Product Passport platform, explaining the architecture and transaction flow together with the prototype implementation and demonstration to showcase the functionality of the solution. Results and analysis provide insights into the challenges of the Circular Economy, sustainable resource management, and the Digital Product Passport, resulting in recommendations for future improvements and enhancements. Overall, this thesis offers a practical solution utilizing DLT to enable transparency and traceability in the Circular Economy, contributing to the realization of sustainable and efficient resource management practices to ultimately contribute to the set Circular Economy initiatives.
Objectives: The MetabQoL 1.0 is the first disease-specific health related quality of life (HrQoL) questionnaire for patients with intoxication-type inherited metabolic disorders. Our aim was to assess the validity and reliability of the MetabQoL 1.0, and to investigate neuropsychiatric burden in our patient population. Methods: Data from 29 patients followed at a single center, aged between 8 and 18 years with the diagnosis of methylmalonic acidemia (MMA), propionic acidemia (PA) or isovaleric acidemia (IVA), and their parents were included. The Pediatric Quality of Life Inventory (PedsQoL) was used to evaluate the validity and reliability of MetabQoL 1.0.
Results: The MetabQoL 1.0 was shown to be valid and reliable (Cronbach's alpha: 0.64–0.9). Fourteen out of the 22 patients (63.6%) formally evaluated had neurological findings. Of note, 17 out of 20 patients (85%) had a psychiatric disorder when evaluated formally by a child and adolescent psychiatrist. The median mental scores of the MetabQoL 1.0 proxy report were significantly higher than those of the self report (p = 0.023). Patients with neonatal-onset disease had higher MetabQoL 1.0 proxy physical (p = 0.008), mental (p = 0.042), total scores (p = 0.022); and self report social (p = 0.007) and total scores (p = 0.043) than those with later onset disease.
Conclusions: This study continues to prove that the MetabQoL 1.0 is an effective tool to measure what matters in intoxication-type inherited metabolic disorders. Our results highlight the importance of clinical assessment complemented by patient reported outcomes which further expands the evaluation toolbox of inherited metabolic diseases.
In engineering design, optimization methods are frequently used to improve the initial design of a product. However, the selection of an appropriate method is challenging since many
methods exist, especially for the case of simulation-based optimization. This paper proposes a systematic procedure to support this selection process. Building upon quality function deployment, end-user and design use case requirements can be systematically taken into account via a decision
matrix. The design and construction of the decision matrix are explained in detail. The proposed
procedure is validated by two engineering optimization problems arising within the design of box-type boom cranes. For each problem, the problem statement and the respectively applied optimization methods are explained in detail. The results obtained by optimization validate the use
of optimization approaches within the design process. The application of the decision matrix shows the successful incorporation of customer requirements to the algorithm selection.
This master thesis investigates leadership traits and how they can drive success within international organizations in the digital era. The basic principles of what defines a leader have undergone significant scrutiny throughout the past one hundred years, however, the digital revolution has created the most upset when considering the requirements for efficient leadership.
This paper utilizes a literature review to first determine how modern leadership theory developed and the implications of current research, followed by an empirical study designed to collect real-world data which represents how current leaders active in various industries understand their role as a leader and what skills they use to promote success within their organization.
Cross-examination of these sources indicates that the most effective leaders employ a combination of Transformational Leadership Theory and Emotional Intelligence-based leadership. The extent to which a leader must individualize their style is strongly contingent on the organizational culture, the individual employees, and the external environment. While traits such as communication, charisma, and trustworthiness are certainly strong indications of an efficient leader, agility and adaptability clearly stand out as the traits which are most required for highly effective leaders in the digital era.
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.