@inproceedings{HopfenspergerVanselowHopkinsetal., author = {Hopfensperger, Bernhard and Vanselow, Marcel and Hopkins, Andrew and Hahn, Ingo}, title = {Investigation of the Effect of Magnetic Coupling on the Capacitor Current of Dual Three-Phase Permanent Magnet Synchronous Machine Drives}, series = {2025 Energy Conversion Congress \& Expo Europe (ECCE Europe); Birmingham, United Kingdom ; 9/1/2025 - 9/4/2025}, booktitle = {2025 Energy Conversion Congress \& Expo Europe (ECCE Europe); Birmingham, United Kingdom ; 9/1/2025 - 9/4/2025}, publisher = {IEEE}, isbn = {979-8-3315-6752-1}, doi = {10.1109/ECCE-Europe62795.2025.11238664}, pages = {6}, abstract = {The drive towards electrification of vehicles and transport systems has led to research into multiphase drive topologies beyond the conventional three. Dual three-phase machine drives are attractive due to reduced torque and DC-link harmonic content in addition to fault tolerance. Further DC-link rms-current reductions can be realised by applying appropriate modulation schemes and shifting/interleaving PWM patterns. However, the magnetic cross coupling between the two three-phase systems impacts the output current harmonics and subsequently the torque ripple which is further exacerbated by interleaving of their respective carriers. The impact of magnetic coupling on the DC-link and output current ripples is investigated.}, language = {en} } @inproceedings{NadimpalliMaierStauferetal., author = {Nadimpalli, Vamsi Krishna and Maier, Robert and Staufer, Susanne and R{\"o}hrl, Simon and Ezer, Timur and Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {EXPERT SURVEYS TO REAL TIME ADAPTATION OF LEARNING PATHS}, series = {ICERI2025 Proceedings}, booktitle = {ICERI2025 Proceedings}, editor = {G{\´o}mez Chova, Luis and Gonz{\´a}lez Mart{\´i}nez, Chelo and Lees, Joanna}, publisher = {IATED}, doi = {10.21125/iceri.2025.1571}, pages = {5677 -- 5687}, abstract = {Learning management systems rely on adaptive algorithms that use learner preferences to personalize the instructional content in form of learning paths. However, these preferences are uncertain in nature, and change over time. The present solutions are either static or purely data-driven missing the dynamic adaption to changes in the preferences and infusion of pedagogical nuances respectively. This paper introduces an extended variant of Nestor, our Bayesian network engine that models personality traits, learning styles, and learning strategies. This extension overlays a lightweight rule-based mechanism whose "secret recipe'' lies in the infusion of expert-derived weights adapting learning paths dynamically whenever a learner selects new material in Moodle. To parameterise these rules, we conducted a structured survey with 12 hand-picked professors and researchers in educational science. Each expert responded to 4 demographic items and 12 item that are distributed across algorithm-overview, scenario-based, and example-based categories, thereby supplying the nuanced weightings that result the personalised recommendations. This hybrid system (Nestor plus the expert-infused rule layer) operated during the winter term of 2025. 18 students completed an end-of-term questionnaire. Although their learning gains were not recorded, the majority of respondents reported positive or neutral experiences with the dynamically adapted learning paths. The {Future work} will compare three engines: (i) the present dynamic, expert-infused rule layer on top of the static Bayesian network, (ii) purely data-driven machine-learning models that neglect expert weighting, and (iii) the original static-adaptation Bayesian network without rules. Analyses of log files, intermediate satisfaction surveys, and pre/post term surveys will clarify whether this on-the-fly adaptation and pedagogical nuance lead to measurable learning benefits.}, language = {en} } @article{SchummHaasPeeretal., author = {Schumm, Leon and Haas, Jannik and Peer, Rebecca and Sterner, Michael}, title = {The role of hydrogen offtaker regulation in highly renewable electricity systems}, series = {Energy}, volume = {342}, journal = {Energy}, publisher = {Elsevier}, doi = {10.1016/j.energy.2025.139513}, pages = {13}, abstract = {The growing demand for green hydrogen necessitates a rapid scale-up of production and exports to meet decarbonization targets globally. However, current ramp-up efforts remain insufficient, calling for policies that unlock the potential of hydrogen as a low-carbon energy carrier. A key lever is the offtaker regulation, which impacts the pace and sustainability of export projects. This study investigates minimum renewable share requirements for hydrogen exports in countries with high renewable electricity shares. Using New Zealand as a case study, we develop a fully sector-coupled capacity expansion and dispatch model, integrating hydrogen and electricity network planning based on PyPSA-Earth. The model optimizes New Zealand's energy system under varying export scenarios, renewable electricity shares, and resulting system impacts. We find that domestic electricity demand and renewable expansion rates dominate long-term outcomes, while progressive regulation enables short-term hydrogen and Power-to-X exports. Relaxing the renewable threshold from 80\% to 60\% triples export volumes from 2.5 TWh to 8.2 TWh by 2030. We propose a two-stage requirement: an initially progressive threshold to attract investment with low consequential emissions, followed by stricter regulation to prevent high emissions, rising domestic electricity prices, and declining hydrogen competitiveness. This framework, demonstrated for New Zealand, can guide hydrogen-exporting countries worldwide.}, language = {en} } @misc{Schoen, type = {Master Thesis}, author = {Sch{\"o}n, Matthias}, title = {Implementation and Evaluation of the ESPRIT Algorithm for DoA Estimation on an FPGA-based SDR Platform}, address = {Regensburg}, doi = {10.35096/othr/pub-8688}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-86883}, school = {Ostbayerische Technische Hochschule Regensburg}, pages = {vi, 104}, abstract = {Environmental sensing using smart antennas and antenna arrays is a broad field with many applications in different areas. This thesis is part of the initial stage of a longer research project at the OTH Regensburg, with the goal of enhancing the antenna-array-based sensing capabilities of base stations. Existing technologies that utilize radio waves, such as radar, often require the generation of special signals to scan the environment. This project aims to utilize the existing mobile communication traffic instead, making the benefits of sensing capabilities available to a wider range of applications. Many of the array processing methods require high computational power and are used in environments with real-time constraints. Therefore, the use of field-programmable gate arrays (FPGAs) for hardware acceleration of these methods will be investigated, evaluating which methods are suitable for implementation on FPGAs. The focus in this thesis lies on the Estimation of Signal Parameters Via Rotational Invariance Techniques (ESPRIT) method for direction of arrival (DoA) estimation, as it is a popular and highly accurate method that does not rely on calibration. The accelerator is implemented for the RFSoC4x2 software-defined radio (SDR), using Vitis High-Level Synthesis (HLS) for implementation of the algorithm itself, Vivado for the hardware configuration, and Python Productivity on Zynq (PYNQ) for drivers and application code. Simulations for evaluation and verification, as well as test data generation, are implemented in Julia, using a custom array signal processing package. A measurement setup is used to collect experimental data for simulation and evaluation of the performance of the implemented ESPRIT. It is shown that the underlying assumption of equal subarrays does not hold for the array used for the measurements. This causes the estimates to be erroneous and can only be addressed by employing other algorithms that allow for the required calibration.}, subject = {Field programmable gate array}, language = {en} } @inproceedings{NadimpalliHauserBittneretal., author = {Nadimpalli, Vamsi Krishna and Hauser, Florian and Bittner, Dominik and Grabinger, Lisa and Staufer, Susanne and Mottok, J{\"u}rgen}, title = {Systematic Literature Review for the Use of AI Based Techniques in Adaptive Learning Management Systems}, series = {Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023}, booktitle = {Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023}, editor = {Mottok, J{\"u}rgen}, publisher = {Association for Computing Machinery}, address = {New York}, isbn = {978-1-4503-9956-2}, doi = {10.1145/3593663.3593681}, pages = {83 -- 92}, abstract = {Nowadays, learning management systems are widely employed in all educational institutions to instruct students as a result of the increasing in online usage. Today's learning management systems provide learning paths without personalizing them to the characteristics of the learner. Therefore, research these days is concentrated on employing AI-based strategies to personalize the systems. However, there are many different AI algorithms, making it challenging to determine which ones are most suited for taking into account the many different features of learner data and learning contents. This paper conducts a systematic literature review in order to discuss the AI-based methods that are frequently used to identify learner characteristics, organize the learning contents, recommend learning paths, and highlight their advantages and disadvantages.}, language = {en} } @misc{Kriegl, author = {Kriegl, Raphael}, title = {Preservation of wetting ridges using field-induced plasticity of magnetoactive elastomers (Version 3) [Data set]}, doi = {10.5281/zenodo.14502155}, abstract = {How to access data: html: Open in browser to view interactive figure pdf/png: Static figure, open with desired program json: Contains data for figures Open using Python pandas: import pandas as pd data = pd.read_json("filename") data then contains a pandas table. The cells in columns describing x,y data might contain entire arrays. Naming: Figure files are named after their respective ordering (i.e. figure1_*). Data and figure files are always named correspondingly. Zip archives (indiv_3D_*.zip) contain multiple additional figures, one for each surface measurement. There is a zip archive with the static renders and one with the interactive plots.}, language = {en} } @misc{GlavanBelyaevaShamoninChamonine, author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail}, title = {On the Piezomagnetism of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields: Height Modulation in the Vicinity of an Operating Point by Time-Harmonic Fields [Data set]}, doi = {10.5281/zenodo.13834054}, language = {en} } @misc{GlavanBelyaevaShamoninChamonine, author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail}, title = {Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform [Data set]}, doi = {10.5281/zenodo.14651784}, language = {en} } @misc{Kriegl, author = {Kriegl, Raphael}, title = {Characterization of Wetting Properties of Magnetoactive Elastomer Surfaces [Data set]}, doi = {10.5281/zenodo.13124610}, language = {en} } @misc{Kriegl, author = {Kriegl, Raphael}, title = {Tunable rebound of millimeter-sized rigid balls by magnetic actuation of elastomer-based surface microstructures [Data set]}, doi = {10.5281/zenodo.10419411}, language = {en} } @article{GlavanBelyaevaShamoninChamonine, author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail}, title = {Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform}, series = {Sensors}, volume = {22}, journal = {Sensors}, number = {10}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/s22103791}, pages = {1 -- 17}, abstract = {In this work, multiferroic cantilevers comprise a layer of a magnetoactive elastomer (MAE) and a commercially available piezoelectric polymer-based vibration sensor. The structures are fixed at one end in the horizontal plane and the magnetic field is applied vertically. First, the magnetoelectric (ME) response to uniform, triangle-wave magnetic fields with five different slew rates is investigated experimentally. Time and field dependences of the generated voltage, electric charge, and observed mechanical deflection are obtained and compared for four different thicknesses of the MAE layer. The ME responses to triangular and sinusoidal wave excitations are examined in contrast. Second, the ME response at low frequencies (≤3 Hz) is studied by the standard method of harmonic magnetic field modulation. The highest ME coupling coefficient is observed in the bias magnetic field strength of ≈73 kA/m and it is estimated to be about 3.3 ns/m (ME voltage coefficient ≈ 25 V/A) at theoretically vanishing modulation frequency (f→0 Hz). Presented results demonstrate that the investigated heterostructures are promising for applications as magnetic-field sensors and energy harvesting devices.}, language = {en} } @misc{Bugert, author = {Bugert, Flemming}, title = {Applying Ariadne: Dataset on Learning Styles and Moodle-Based Learning Paths [Data set]}, doi = {10.5281/zenodo.12594911}, abstract = {This dataset contains information queried from 22 students inside a Moodle based learning management system during the winter term 2023/24 at a German university. Abstract With the use of learning management systems students benefit from being recommended suitable learning elements based on their individual needs. In doing so, recommendation algorithms are applied which first query the student's learning style. To improve the recommendation of learning elements a continuous analysis of the individual's learning style is required. A frequent questionnaire assessment would however be too time consuming. Instead, in a prior study an algorithm has been designed to identify changes in learning styles from the student's selection of learning elements. In this paper, we investigate the functionality of that algorithm by applying it on real student data. In particular, we test if the algorithm correctly indicates changes in learning styles. The utilised data is collected in our learning management system. To be precise, the data is obtained from 22 students enrolled in a software engineering course during the winter term of 2023/24. The data comprises two types of information for each student: 1) learning style collected at the start and end of the term, and 2) the user's actual selection of learning elements inside the learning management system. The uniqueness of this study lies in the data and the evaluation strategy based on it. Having the learning style at the end of the semester period as ground truth allows us to test if the algorithm operates correctly with actual user data from our learning management system. The results validate the behaviour of our algorithm, yet they strongly suggest the need for an adaptation. Further research is required on how to parameterise the underlying models.}, language = {en} } @article{KrieglJezeršekKravanjaetal., author = {Kriegl, Raphael and Jezeršek, Matija and Kravanja, Gaia and Hribar, Luka and Mukhi, Soham and Kokot, Gašper and Drevenšek-Olenik, Irena and Shamonin (Chamonine), Mikhail}, title = {Tunable rebound of millimeter-sized rigid balls by magnetic actuation of elastomer-based surface microstructures}, series = {Smart Materials and Structures}, volume = {33}, journal = {Smart Materials and Structures}, number = {6}, publisher = {IOP Publishing}, doi = {10.1088/1361-665X/ad41a9}, abstract = {A novel method for controlling the rebound behavior of small balls made of Al2O3 with a radius of 2.381 mm is presented. It uses different types of micro-structured surfaces of soft magnetoactive elastomers. These surfaces were fabricated via laser micromachining and include fully ablated surfaces as well as micrometer-sized lamellas with a fixed width of 90 µm, height of 250 µm and three different gap sizes (15, 60 and 105 µm). The lamellas can change their orientation from edge-on to face-on configuration according to the direction of the external magnetic field from a permanent magnet. The orientation of the external magnetic field significantly influences the rebound behavior of the balls, from a coefficient of restitution e of to < 0.1. The highest relative change in the coefficient of restitution between zero field and face-on configuration of is observed for lamellas with a gap of 60 µm. Other characteristics of the ball rebound such as the penetration depth into an Magnetoactive elastomer and the maximum deceleration are investigated as well. The proposed method does not require a constant power supply due to the use of permanent magnets. It may find novel applications in the field of impact engineering.}, language = {en} } @misc{Staufer, author = {Staufer, Susanne}, title = {Persistence of Learning Style, Learning Strategy, and Personality Traits [Data set]}, doi = {10.5281/zenodo.12743866}, abstract = {This dataset contains the result of the survey to learning styles, learning strategies, and personality traits. The survey was executed in winter term 2023/24 and summer term 2023 in a German university (OTH Regensburg) during the course "Software Engineering". Examined questionnaires are ILS (learning styles), LIST-K (learning strategies), and BFI-10 (personality traits). The same three questionnaires were asked at two different survey periods three to four months apart while each survey period lasts one to two weeks. Pretest data were examined at the start of the term, while posttest data at the end.}, language = {en} } @inproceedings{BittnerEzerGrabingeretal., author = {Bittner, Dominik and Ezer, Timur and Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Unveiling the secrets of learning styles: decoding eye movements via machine learning}, series = {Proceedings of the 16th annual International Conference of Education, Research and Innovation (ICERI 2023), Seville, Spain, 11/13/2023 - 11/14/2023}, booktitle = {Proceedings of the 16th annual International Conference of Education, Research and Innovation (ICERI 2023), Seville, Spain, 11/13/2023 - 11/14/2023}, editor = {G{\´o}mez Chova, Luis and Gonz{\´a}lez Mart{\´i}nez, Chelo and Lees, Joanna}, publisher = {IATED}, isbn = {978-84-09-55942-8}, doi = {10.21125/iceri.2023.1291}, pages = {5153 -- 5162}, abstract = {Universities are faced with a rising number of dropouts in recent years. This is largely due to students' limited capability of finding individual learning paths through various course materials. However, a possible solution to this problem is the introduction of adaptive learning management systems, which recommend tailored learning paths to students - based on their individual learning styles. For the classification of learning styles, the most commonly used methods are questionnaires and learning analytics. Nevertheless, both methods are prone to errors: questionnaires may give superficial answers due to lack of time or motivation, while learning analytics do not reflect offline learning behavior. This paper proposes an alternative approach to classify students' learning styles by integrating eye tracking in combination with Machine Learning (ML) algorithms. Incorporating eye tracking technology into the classification process eliminates the potential problems arising from questionnaires or learning analytics by providing a more objective and detailed analysis of the subject's behavior. Moreover, this approach allows for a deeper understanding of subconscious processes and provides valuable insights into the individualized learning preferences of students. In order to demonstrate this approach, an eye tracking study is conducted with 117 participants using the Tobii Pro Fusion. Using qualitative and quantitative analyses, certain patterns in the subjects' gaze behavior are assigned to their learning styles given by the validated Index of Learning Styles (ILS) questionnaire. In short, this paper presents an innovative solution to the challenges associated with classifying students' learning styles. By combining eye tracking data with ML algorithms, an accurate and insightful understanding of students' individual learning paths can be achieved, ultimately leading to improved educational outcomes and reduced dropout rates.}, language = {en} } @misc{RahimSchumm, author = {Rahim, Stefan and Schumm, Leon}, title = {Weather Data Cutouts for the Wasserstoffatlas (Hydrogen Map) [Data set]}, doi = {10.5281/zenodo.8135586}, abstract = {The cutouts are required to calculate the solar PV and wind onshore feed-in profiles of the Wasserstoffatlas. The provided cutouts are spatiotemporal subsets of the European weather data from the ECMWF ERA5 reanalysis dataset and the CMSAF SARAH-2 solar surface radiation dataset for the year 2013. They have been prepared by and are for use with the atlite tool (https://atlite.readthedocs.io/). ECMWF ERA5 Source: https://cds.climate.copernicus.eu/cdsapp\#!/dataset/reanalysis-era5-single-levels?tab=overview Terms of Use: https://cds.climate.copernicus.eu/api/v2/terms/static/20180314_Copernicus_License_V1.1.pdf CMSAF SARAH-2 Pfeifroth, Uwe; Kothe, Steffen; M{\"u}ller, Richard; Trentmann, J{\"o}rg; Hollmann, Rainer; Fuchs, Petra; Werscheck, Martin (2017): Surface Radiation Data Set - Heliosat (SARAH) - Edition 2, Satellite Application Facility on Climate Monitoring, DOI:10.5676/EUM_SAF_CM/SARAH/V002, https://doi.org/10.5676/EUM_SAF_CM/SARAH/V002 Terms of Use: https://www.eumetsat.int/cs/idcplg?IdcService=GET_FILE\&dDocName=pdf_leg_data_policy\&allowInterrupt=1\&noSaveAs=1\&RevisionSelectionMethod=LatestReleased}, language = {en} } @misc{BittnerEzerGrabingeretal., author = {Bittner, Dominik and Ezer, Timur and Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Eye Tracking based Learning Style Identification for Learning Management Systems [Data set]}, doi = {10.5281/zenodo.8349468}, abstract = {In recent years, universities have been faced with increasing numbers of students dropping out. This is partly due to the fact that students are limited in their ability to explore individual learning paths through different course materials. However, a promising remedy to this issue is the implementation of adaptive learning management systems. These systems recommend customised learning paths to students - based on their individual learning styles. Learning styles are commonly classified using questionnaires and learning analytics, but both methods are prone to error. Questionnaires may yield superficial responses due to time constraints or lack of motivation, while learning analytics ignore offline learning behaviour. To address these limitations, this study aims to integrating Eye Tracking for a more accurate classification of students' learning styles. Ultimately, this comprehensive approach could not only open up a deeper understanding of subconscious processes, but also provide valuable insights into students' unique learning preferences.}, language = {en} } @misc{BirettSchummHofrichteretal., author = {Birett, Falk and Schumm, Leon and Hofrichter, Andreas and Heusgen, Valentin and Rahim, Stefan}, title = {Wasserstoffatlas Deutschland (Hydrogen Map) [Data set]}, doi = {10.5281/zenodo.13960465}, abstract = {Input files required for Hydrogen Map workflow in the project "Wasserstoffatlas Deutschland", funded by the BMBF.}, language = {en} } @misc{GrabingerHomannHauseretal., author = {Grabinger, Lisa and Homann, Alexander and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Study: MISRA C coding guidelines [Data set]}, doi = {10.5281/zenodo.7898606}, abstract = {This repository contains the material and obtained data of an eye tracking study on the topic "MISRA C coding guidelines".}, language = {en} } @misc{GrabingerHauserMottok, author = {Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Study: Notation of Causal Graphs [Data set]}, doi = {10.5281/zenodo.7241158}, abstract = {This repository contains the material and obtained data of an eye tracking study on the topic "Notation of Causal Graphs".}, language = {en} } @misc{GrabingerHauserMottok, author = {Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Study: Layout of Causal Graphs [Data set]}, doi = {10.5281/zenodo.7241097}, abstract = {This repository contains the material and obtained data of an eye tracking study on the topic "Layout of Causal Graphs".}, language = {en} } @misc{Kriegl2022, author = {Kriegl, Raphael}, title = {Microstructured Magnetoactive Elastomers for Switchable Wettability [Data set]}, doi = {10.5281/zenodo.13124555}, year = {2022}, language = {en} } @misc{GlavanBelyaevaShamoninChamonineetal., author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail and Ruwisch, Kevin and Wollschl{\"a}ger, Joachim}, title = {Magnetoelectric Response of Laminated Cantilevers Comprising a Magnetoactive Elastomer and a Piezoelectric Polymer, in Pulsed Uniform Magnetic Fields [Data set]}, doi = {10.5281/zenodo.14652152}, language = {en} } @misc{GlavanBelyaevaShamoninChamonine, author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail}, title = {Transient Response of Macroscopic Deformation of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields [Data set]}, doi = {10.5281/zenodo.10679499}, language = {en} } @article{GlavanBelyaevaShamoninChamonine, author = {Glavan, Gašper and Belyaeva, Inna A. and Shamonin (Chamonine), Mikhail}, title = {Transient Response of Macroscopic Deformation of Magnetoactive Elastomeric Cylinders in Uniform Magnetic Fields}, series = {Polymers}, volume = {16}, journal = {Polymers}, number = {5, Special Issue Magnetic Polymer Composites: Design and Application II}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2073-4360}, doi = {10.3390/polym16050586}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-71067}, pages = {17}, abstract = {Significant deformations of bodies made from compliant magnetoactive elastomers (MAE) in magnetic fields make these materials promising for applications in magnetically controlled actuators for soft robotics. Reported experimental research in this context was devoted to the behaviour in the quasi-static magnetic field, but the transient dynamics are of great practical importance. This paper presents an experimental study of the transient response of apparent longitudinal and transverse strains of a family of isotropic and anisotropic MAE cylinders with six different aspect ratios in time-varying uniform magnetic fields. The time dependence of the magnetic field has a trapezoidal form, where the rate of both legs is varied between 52 and 757 kA/(s·m) and the maximum magnetic field takes three values between 153 and 505 kA/m. It is proposed to introduce four characteristic times: two for the delay of the transient response during increasing and decreasing magnetic field, as well as two for rise and fall times. To facilitate the comparison between different magnetic field rates, these characteristic times are further normalized on the rise time of the magnetic field ramp. The dependence of the normalized characteristic times on the aspect ratio, the magnetic field slew rate, maximum magnetic field values, initial internal structure (isotropic versus anisotropic specimens) and weight fraction of the soft-magnetic filler are obtained and discussed in detail. The normalized magnetostrictive hysteresis loop is introduced, and used to explain why the normalized delay times vary with changing experimental parameters.}, language = {en} } @article{GrabingerHauserWolffetal., author = {Grabinger, Lisa and Hauser, Florian and Wolff, Christian and Mottok, J{\"u}rgen}, title = {On Eye Tracking in Software Engineering}, series = {SN Computer Science}, volume = {5}, journal = {SN Computer Science}, number = {6}, publisher = {Springer}, address = {Singapore}, issn = {2661-8907}, doi = {10.1007/s42979-024-03045-3}, abstract = {Eye tracking is becoming more and more important as a research method within the field of software engineering (SE). Existing meta-analyses focus on the design or conduct of SE eye tracking studies rather than the analysis phase. This article attempts to fill this gap; it presents a systematic literature review of eye tracking studies in the field of SE—focusing mainly on the data analysis methods used. From the IEEE Xplore and ACM digital libraries we gather 125 papers up to the first quarter of 2024. Detailed evaluation provides information on the number of papers that use specific methods of analysis (i.e., descriptive or inferential statistics, and gaze visualization) or settings (e.g., sample size, technical setup, and selected aspects of research design). With the data obtained we can infer the popularity of specific analysis methods in the field. Those results enable efficient work on data analysis tools or education of aspiring researchers and can serve as basis for standardization or guidelines within the community—providing for methods to include as well as current inconsistencies.}, language = {en} } @inproceedings{HammerMottokKrauseetal., author = {Hammer, Pascal and Mottok, J{\"u}rgen and Krause, Veronika and Probst, Tobias}, title = {Approach for High-Performance Random Number Generators for Critical Systems}, series = {Proceeding of the 12th European Congress on Embedded Real Time Software and Systems (ERTS2024) , Toulouse, 11-12 June 2024}, booktitle = {Proceeding of the 12th European Congress on Embedded Real Time Software and Systems (ERTS2024) , Toulouse, 11-12 June 2024}, doi = {10.5281/zenodo.14848832}, pages = {9}, abstract = {In times of digitalization, the encryption and signing of sensitive data is becoming increasingly important. These cryptographic processes require large quantities of high-quality random numbers. Which is why a high-performance random number generator (RNG) is to be developed. For this purpose, existing concepts of RNGs and application standards are first analyzed. The proposed approach is to design a physical true random number generator (PTRNG) with a high output of random numbers. Based on this, the development begins with the analog part of the RNG, the noise signal source and a suitable amplifier for the analog noise signal. Therefore, a special noise diode from Noisecom and an amplifier from NXP were chosen and analyzed in different measurements. From the results of the measurements, it can be concluded that both components are suitable for use in the RNG.}, language = {en} } @misc{Grabinger, author = {Grabinger, Lisa}, title = {Data of a systematic literature research on eye tracking in software engineering [Data set]}, doi = {10.5281/zenodo.11279180}, abstract = {How did the data collection work? By systematic research in the IEEE Xplore and ACM digital libraries we extracted 125 papers. Further details on the procedure can be found in the journal paper. What data is provided? In this repository you can find the extracted data, i.e., file data.xlsx.}, language = {en} } @inproceedings{UhlSchamelAchhammeretal., author = {Uhl, Julius and Schamel, Marco and Achhammer, Anton and Sterner, Michael}, title = {Sustainable Steel Production in the Desert: Economic and Technical Assessment of a Hydrogen-Powered Steel Plant in Mauritania}, series = {2025 IEEE PES/IAS PowerAfrica, 28 September - 02 October 2025, Cairo}, booktitle = {2025 IEEE PES/IAS PowerAfrica, 28 September - 02 October 2025, Cairo}, publisher = {IEEE}, doi = {10.1109/PowerAfrica65840.2025.11289120}, pages = {6}, abstract = {The global steel industry is a major contributor to climate change and faces challenges in achieving a carbon-neutral production, hinging on the availability of cost-effective hydrogen produced by renewable energy. Mauritania, with its exceptional solar and wind resources, offers some of the most competitive conditions globally for hydrogen production. Instead of focusing on hydrogen exports, this study explores the technical feasibility and economic viability of establishing a renewable-powered steel plant in Mauritania, utilizing the country's abundant iron ore reserves. The findings suggest that sustainably produced steel in Mauritania could be cost-competitive with current European prices. With ongoing declines in investment costs for emerging renewable technologies, Mauritania has the potential to become one of the world's most cost-effective steel producers.}, language = {en} } @inproceedings{HinterreiterBruecklRauch, author = {Hinterreiter, Marion and Br{\"u}ckl, Oliver and Rauch, Johannes}, title = {Methodology for long-term reactive power forecasts of medium-voltage grids}, series = {NEIS 2025 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg, September 15 - 16, 2025}, booktitle = {NEIS 2025 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg, September 15 - 16, 2025}, editor = {Schulz, Detlef}, publisher = {VDE Verlag}, isbn = {978-3-8007-6633-8}, pages = {218 -- 223}, abstract = {Understanding and assessing the long-term behavior of reactive power is crucial for power system planning and invest-ment decisions. This is particularly growing relevant for the lower voltage-grid levels, which are gaining importance due to significant changes in grid behavior, operational strategies, energy generation and consumption patterns. Currently, standardized methodologies for forecasting reactive power in medium-voltage grids are lacking, creating a gap in research and practical applications. To optimize grid investments and expansions, informed decisions based on reliable research and accurate forecasts are essential. This paper presents a methodology for long-term reactive power forecasting in me-dium-voltage grids, introducing a new approach to account for low- and medium-voltage grid interactions while address-ing common challenges like limited available grid data and scenario framework definition. The aim of the forecast is the future reactive power behaviour of a medium-voltage-grid at the high-voltage side of the high-voltage to medium-voltage transformer. The medium-voltage-level is modelled using a grid model approach, while low-voltage grids are being mod-elled using generic distribution grids. A 209-bus medium-voltage-grid model is used as an application example and to provide two exemplary use cases for a reactive power forecast for 2045.}, language = {en} } @inproceedings{StadlerKrausBrueckl, author = {Stadler, Andreas and Kraus, Hermann and Br{\"u}ckl, Oliver}, title = {Proposing an Optimization Model for a techno-economic Evaluation of Energy Storage Systems}, series = {PESS 2025 - IEEE Power and Energy Student Summit, October 08 - 10, 2025 in Munich, Germany}, booktitle = {PESS 2025 - IEEE Power and Energy Student Summit, October 08 - 10, 2025 in Munich, Germany}, editor = {Technische Universit{\"a}t M{\"u}nchen,}, publisher = {VDE}, isbn = {978-3-8007-6656-7}, pages = {97 -- 102}, abstract = {During the global energy crisis in 2022, electricity prices increased drastically. This lead, together with an overall higher price volatility to possibly higher electrical energy storage system (ESS) profitability. To test if the investment in an ESS can now be more profitable, an approach for a techno-economic evaluation of ESS is presented in this paper, using an optimization algorithm to determine the optimal way of covering a load flow profile with electricity trading products on the electricity market with and without the use of an energy storage system. The cost differences between using or not using the storage system are assumed to be the profits of the ESS, which must exceed the (interest-bearing) investment costs over its lifetime. The correct way of operation of the optimization model is validated and several storage sizes and capacities as well as several years of the electricity market data was analyzed, once with a perfect forecast of all prices of the electricity trading products and once with a forecast based on the previous years purchasing strategy. The results show that, using the prognosis and a 2 \% p.a. interest rate, only the storage combinations for 2.5 MWh/ 2.5 MW and 1 MWh/ 1 MW show profitability in 2023, whereas 2017 and 2020 show no profitability.}, language = {en} } @article{SchiekSolntsevNeshev2025, author = {Schiek, Roland and Solntsev, Alexander S. and Neshev, Dragomir N.}, title = {Measurement of the cubic nonlinear susceptibility in lithium niobate}, series = {Optical Materials Express}, volume = {15}, journal = {Optical Materials Express}, number = {5}, publisher = {Optica Publishing Group}, issn = {2159-3930}, doi = {10.1364/OME.557516}, pages = {1100 -- 1117}, year = {2025}, abstract = {We measured the cubic nonlinear susceptibility tensor elements ( χ(3)) for polarization along the primary crystallographic axis in titanium-indiffused lithium niobate waveguides, assessed through self-phase modulation using picosecond-duration pulses at telecommunication wavelengths. A dominant, highly temperature- and wavelength-dependent contribution from a cascaded second-order nonlinearity is observed. Through careful extraction of the cascaded effect, we quantify the intrinsic third-order susceptibility tensor elements as χ(3) zzzz(ω; ω, ω, -ω) = (5.2 ± 1.3) × 10-21 m2 V2 and χ(3) xxxx(ω; ω, ω, -ω) = χ(3) yyyy(ω; ω, ω, -ω) = (3.6 ± 0.8) × 10-21 m2 V2 . These measurements underscore the substantial impact of the cascaded nonlinearity in enhancing the effective cubic nonlinearity in lithium niobate and offer precise values essential for the design of nonlinear photonic devices.}, language = {en} } @inproceedings{HinterreiterBruecklRauch, author = {Hinterreiter, Marion and Br{\"u}ckl, Oliver and Rauch, Johannes}, title = {Challenges and Approaches for Long-Term Reactive Power Forecasting in Power Systems}, series = {PESS 2025 - IEEE Power and Energy Student Summit, October 08 - 10, 2025 in Munich, Germany}, booktitle = {PESS 2025 - IEEE Power and Energy Student Summit, October 08 - 10, 2025 in Munich, Germany}, editor = {Technische Universit{\"a}t M{\"u}nchen,}, publisher = {VDE Verlag}, isbn = {978-3-8007-6656-7}, pages = {109 -- 114}, abstract = {The transition from fossil fuels to renewable energy sources is driving profound changes across all voltage levels of the electrical grid, altering active power (P) as well as reactive power (Q) behavior. This transformation involves a shift from predominantly top-down, unidirectional electricity flows to bidirectional and increasingly complex flow patterns, fundamentally altering the operation and utilization of power systems. Many countries are already reporting notable changes in their transmission grid Q. This can lead to increased costs for grid expansion and compensation equipment, as well as grid losses. To minimize these losses and ensure grid stability and efficiency, understanding and forecasting Q long-term becomes essential. This paper addresses the challenges of long-term (1-20 years) Q forecasting in general by analyzing Q behavior in grids, the main influencing grid parameters, and reviewing existing forecasting approaches. It evaluates the applicability of these approaches and highlights current research gaps and trends. By focusing on this underexplored area, the paper aims to support the development of more advanced and reliable long-term Q forecasting techniques.}, language = {en} } @inproceedings{RauchBruecklEngel, author = {Rauch, Johannes and Br{\"u}ckl, Oliver and Engel, Bernd}, title = {Optimal Reactive Power Planning by covering deficient voltage demands with additional reactive power sources using a sensitivity approach}, series = {NEIS 2023 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg, September 4 - 5, 2023}, booktitle = {NEIS 2023 : Conference on Sustainable Energy Supply and Energy Storage Systems, Hamburg, September 4 - 5, 2023}, editor = {Schulz, Detlef,}, publisher = {VDE Verlag}, address = {Berlin}, isbn = {978-3-8007-6134-0}, pages = {223 -- 230}, abstract = {The determination of the optimal location, types and size of additional required reactive power sources is a main interest of Reactive Power Planning (RPP) investigations and of this paper. The planning problem addresses the maintenance of voltage stability, which is an ancillary service in Germany, and can be formulated as a mixed-integer optimization prob-lem. The aim of this work is a techno-economically efficient coverage of the deficient steady state voltage deviation demands (VDD) by placing new reactive power sources with adequate size or extending the reactive power potential of existing sources. An optimization model is set up to solve the planning problem by using load flow voltage sensitivities, which quantify and evaluate the technical efficiency of new reactive power sources in relation to the present voltage deviation demands. Operating and investment costs are used as economic decision parameters. Within an application example, which is carried out with an exemplary transmission system, the solution of the planning problem is discussed.}, language = {en} } @phdthesis{Thema, author = {Thema, Martin Jiř{\´i}}, title = {Process optimization for microbial biosynthesis of methane in a trickle-bed reactor for Power-to-Gas applications: the ORBIT-process}, isbn = {978-3-8440-7656-1}, url = {http://nbn-resolving.de/https://nbn-resolving.org/urn:nbn:de:bvb:29-opus4-150567}, pages = {XVIII, 211}, abstract = {This thesis identifes Power-to-Gas in general and biological CO2-methanation in trickle-bed reactors in particular as promising energy storage and sector coupling technology ready for application but with further optimization potential. It reviews the global status and development of Power-to-Gas technology as to be of exponentially growing importance in energy systems changing towards renewable power supply and analyzes optimization and standardization potential for biological CO2-methanation in tricklebed reactors deriving an improved methanation process. Process development and experiments on hydrodynamical and biological improvement of such a setup were performed, leading to an optimized combination of a packing and microorganisms in pure culture embedded in the new ORBIT-process. First experimental results give evidence of successful application of different optimization approaches implemented in a technical center scale setup.}, language = {en} } @phdthesis{Lalo, author = {Lalo, Erjola}, title = {Deployment designs for multi-core-real time systems}, edition = {1. Auflage}, publisher = {Universit{\"a}tsverlag Regensburg}, address = {Regensburg}, isbn = {978-3-86845-181-8}, doi = {10.21268/20240712-0}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:104-20240712-00000-7}, pages = {iii, 371}, abstract = {In modern embedded automotive systems, multi-core processors are used to provide higher execution performance and more computing capacity. However, they influence the way these systems are designed. Each change of the platform and application software results in an effort required to ensure and validate the functional correctness and timing requirements of these systems in a multi-core platform. For this reason, the use of the Logical Execution Time (LET) paradigm is advantageous for multi-core systems, as it satisfies these requirements by providing time and dataflow determinism, thereby reducing the development cycle and the impact of the platform in the design of such systems. To integrate LET into these systems, special mechanisms are required to satisfy its semantics. Therefore, this work focuses on buffering and scheduling techniques for resource efficient integration of LET in automotive systems. A buffering mechanism and an automatic schedule synthesis are proposed to guarantee functional correctness, timing requirements, and LET semantics and to reduce the increased demands of LET for memory and processor resources. A static and global buffering protocol is proposed, which compared to lock-based protocols has plausible memory needs and zero-communication overheads at the boundaries of LET intervals. The automatic schedule synthesis considers the Operating System (OS) overheads such that scheduling is optimized with respect to context-switching overheads caused by preemption. Buffering implements most of the LET semantics, but it provides no guarantee that tasks execute within their LET intervals. If scheduling is not designed to ensure that all tasks execute within their LET intervals, then functional correctness and LET semantics are violated. The manual design of a feasible schedule that satisfies the semantics and additional requirements of the application is inefficient and requires a significant amount of effort. Therefore, an automatic schedule generation approach for the Fixed-Priority Scheduling (FPS) and Time-Triggered Scheduling (TTS) is proposed. FPS is the widely used mechanism in the automotive domain because of its flexibility to handle dynamic changes of highly event-driven applications. Recently, TTS has attracted considerable attention in this domain to increase deterministic execution of tasks and efficient planning of processor resources. Therefore, schedule synthesis of FPS and TTS is provided to identify the efficiency, practicality, and resource optimization abilities of each approach for LET systems. To show the practicality of LET for industrial automotive systems, its integration into the software architecture of the classic platform of AUTomotive Open System Architecture (AUTOSAR) is described and a case study is conducted using a real world system.}, language = {en} } @phdthesis{Renner, author = {Renner, Sebastian}, title = {Secure Lightweight Authenticated Encryption for Critical Infrastructures in the Internet of Things}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20230922-1703211-1-0}, pages = {xix, 135}, abstract = {The cryptographic protection of transmitted data on resource-constraint IoT devices presents a difficult challenge. In this thesis, a benchmarking framework for the performance evaluation of lightweight encryption algorithms is introduced. It is analyzed, if and when novel encryption algorithms are more suitable for IoT use cases than the current standard. Besides comparing the sole performance, the cost for hardening the algorithms against side-channel analysis is discussed.}, language = {en} } @phdthesis{Grauvogl, author = {Grauvogl, Dominik}, title = {Multiphysikalische Auslegung einer fremderregten Synchronmaschine mit magnetischer Asymmetrie f{\"u}r einen Hochvolt-Achsantrieb}, editor = {Gerling, Dieter}, publisher = {Shaker Verlag}, address = {D{\"u}ren}, isbn = {9783844085532}, pages = {260}, abstract = {In der vorliegenden Arbeit wird eine fremderregte Synchronmaschine als Achsantrieb f{\"u}r ein Elektrofahrzeug entwickelt. Als Grundlage hierf{\"u}r dient ein bereits vorhandener Stator einer permanenterregten Synchronmaschine. Durch die Wiederverwendung des Stators ist eine maschinentypunabh{\"a}ngige Baukastenerweiterung in Form eines magnetfreien Rotors gegeben, wodurch die {\"o}konomischen und {\"o}kologischen Nachteile der Permanentmagnete ausgeschlossen sind. Bei der Auslegung des Rotors wird von Beginn an ein multiphysikalischer Entwicklungsansatz gew{\"a}hlt, mit dem der praxistaugliche Einsatz f{\"u}r den modularen Baukasten sichergestellt ist. Dabei ist die elektromagnetische Auslegung iterativ auf die mechanische Blechpaketfestigkeit, das thermische Verhalten und die magnetischen Ger{\"a}usche abgestimmt. In Kombination mit den gesetzten Restriktionen ergibt sich ein neuartiges asymmetrisches Polschuhdesign mit dem es m{\"o}glich ist, das geforderte Drehmoment mit gen{\"u}gend kleiner Welligkeit ohne eine Rotorschr{\"a}gung zu erreichen. Die Simulationsergebnisse sind durch die Vermessung eines aufgebauten Prototyps validiert und best{\"a}tigt. Ein abschließender Simulationsvergleich mit der baugleichen permanenterregten Synchronmaschine zeigt, dass die fremderregte Synchronmaschine hinsichtlich Performance, Wirkungsgrad und Ger{\"a}uschverhalten eine konkurrenzf{\"a}hige Alternative dazu ist.}, language = {en} } @phdthesis{Weiss, author = {Weiß, Nils}, title = {Security testing in safety-critical networks}, pages = {xiv, 126}, abstract = {The evolution of cars from mechanical systems to rolling computers creates new requirements for safety and security engineering. Nowadays, every vehicle contains a safety-critical real-time communication network to fulfill its function. Especially the increasing connectivity of automotive systems enlarged the attack surface for cyber-attacks. Safety engineering in this area is well understood and studied for decades, though the security engineering of these systems needs further research. This thesis introduces a black-box investigation process to analyze existing auto-motive systems and components and identifies security vulnerabilities in four different ECUs. Combined with a survey of published security research, vehicle-internal networks are identified as an extraordinary threat to the vehicle's safety and security. The outstanding automation capabilities of security tests for these networks are leveraged in the second part of this thesis. In order to create automated tools for automotive networks, a software foundation is necessary. As part of this thesis, a comprehensive open-source software framework for security testing in vehicular networks was developed and published. This aims to support further security research based on open and free software. Novel tools for the automated identification and exploration of attack surfaces in automotive diagnostic protocol implementations are created and evaluated. These tools allow the creation of comparable attack surface metrics through black-box scans of arbitrary ECUs. Automata learning and system state reverse-engineering techniques highly increase the exploration capabilities of the presented tools. The exploration algorithm is tested on thirteen different ECUs from independent OEMs. All gathered results are evaluated and discussed in the final part of this thesis. Finally, open issues and further research based on this contribution are discussed.}, language = {en} } @article{StrausKravanjaKriegletal., author = {Straus, Izidor and Kravanja, Gaia and Kriegl, Raphael and Shamonin (Chamonine), Mikhail and Drevenšek-Olenik, Irena and Jezeršek, Matija and Kokot, Gašper}, title = {Laser Micromachining for Polymer Surface Topography Designt}, series = {JoVE journal : engineering}, journal = {JoVE journal : engineering}, publisher = {JoVE}, doi = {10.3791/68126}, pages = {15}, abstract = {Soft magnetoactive elastomers (MAEs) are smart materials that respond to external magnetic fields by dynamically altering their mechanical properties. They are composed of magnetically responsive microparticles embedded within a soft polymer matrix, exhibiting an effective shear modulus of up to 100 kPa. In recent decades, MAEs' bulk properties have been successfully exploited for applications such as dynamic vibration damping, vibration sensing, and actuation in soft robotics. Recent research has shifted to their surface properties, revealing promising results on tunable surface features such as roughness, adhesion, and wetting. Even the transport of small solid and fluid objects was demonstrated. The associated surface effects can be significantly enhanced through the precise engineering of surface topography. In this article, an efficient laser micromachining technique, with a resolution of 15 µm, is presented, which enables rapid prototyping of MAE surfaces. It allows the creation of various complex shapes and offers functionality beyond the one achievable with traditional molding techniques. Additionally, the approach is versatile and can be applied to any polymer that sufficiently absorbs the laser light. As an example, a lamellar surface micro-pattern fabrication process and its characterization by optical and scanning electron microscopies are shown. Its response to a magnetic field is demonstrated. The technique provides a flexible and fast solution for optimizing polymer surface design across a wide range of applications.}, language = {en} } @incollection{Sterner, author = {Sterner, Michael}, title = {WBGU Gutachten - zukunftsf{\"a}hige Bioenergie und nachhaltige Landnutzung}, series = {Biomasse \& Abfall : Emissionen mindern und R{\"u}ckst{\"a}nde nutzen (Verfahren \& Werkstoffe f{\"u}r die Energietechnik ; 5)}, booktitle = {Biomasse \& Abfall : Emissionen mindern und R{\"u}ckst{\"a}nde nutzen (Verfahren \& Werkstoffe f{\"u}r die Energietechnik ; 5)}, editor = {Faulstich, Martin and Mocker, Mario}, publisher = {Dorner Printconcept}, address = {Sulzbach-Rosenberg}, isbn = {9783981039146}, pages = {23 -- 28}, language = {de} } @inproceedings{PozzobonWeissMottoketal., author = {Pozzobon, Enrico and Weiß, Nils and Mottok, J{\"u}rgen and Matoušek, V{\´a}clav}, title = {Fuzzy fault injection attacks against secure automotive bootloaders}, series = {21th escar Europe : The World's Leading Automotive Cyber Security Conference (Hamburg, 15. - 16.11.2023)}, booktitle = {21th escar Europe : The World's Leading Automotive Cyber Security Conference (Hamburg, 15. - 16.11.2023)}, publisher = {Ruhr-Universit{\"a}t Bochum}, doi = {10.13154/294-10381}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:294-103817}, pages = {20}, abstract = {Secure embedded bootloaders are the trust anchors for modern vehicles' software. The secure software update process of ECUs is well-defined across the entire automotive industry. Every OEM has his own implementation, but follows the general software update process. This paper demonstrates code execution attacks by combining software and hardware weaknesses in secure automotive bootloaders. The attack can be performed entirely automated, no static code analysisis required. Random fault injection parameters were sufficient to obtain code execution in a reasonable time. All experiments were conducted with electromagnetic fault injection and without any hardware modifications of the targets. We successfully performed our attack on two entirely different gateway Electronic Control Units (ECUs) used in current vehicles (at the time of this research) from Volkswagen and BMW. As a result of this attack, consisting of a combination of a hardware and asoftware attack, the general secure software update process used in the automotive industry needs to be revised.}, language = {en} } @inproceedings{BruecklHaslbeckVogl, author = {Br{\"u}ckl, Oliver and Haslbeck, Matthias and Vogl, Bettina}, title = {Interpretation von P-Q-Wolken als Hilfsmittel zur Bewertung von Mittelspannungsnetzen}, series = {4. OTTI Konferenz: Zuk{\"u}nftige Stromnetze 31.01- 01.02.2017, Berlin}, booktitle = {4. OTTI Konferenz: Zuk{\"u}nftige Stromnetze 31.01- 01.02.2017, Berlin}, pages = {6}, abstract = {Zwischen {\"U}bertragungs-/Verteilungsnetzbetreibern bestehen Vereinbarungen in Form von Vertr{\"a}gen und Richtlinien (z.B. DCC), die das zul{\"a}ssige Wirk- und Blindleistungs-Verhalten (P-Q-Verhalten) beschreiben. Beim Blindleistungsverhalten werden i. d. R. zul{\"a}ssige cosφ-Bereiche definiert. Typische Werte sind hierf{\"u}r cosφ ≤ 0,95 f{\"u}r den I. und II. Quadranten sowie cosφ ≤ 0,925 f{\"u}r den III. Quadranten. Der IV. Quadrant ist unzul{\"a}ssig. Netzstruktur, Verbraucher und Erzeuger beeinflussen das P-Q-Verhalten, weshalb die Einhaltung der cosφ-Grenzwerte bei sich {\"a}ndernden Faktoren zu pr{\"u}fen und ggf. Gegenmaßnahmen (z. B. Installation von Kompensationsdrosseln) zu ergreifen sind. Ziel dieser Ver{\"o}ffentlichung ist es, geeignete Parameter zu identifizieren und zu beschreiben, die einen Einfluss auf das P-Q-Verhalten und damit auf die Form der PQ- Wolke einer MS-Netzgruppe (MS-NG) aufweisen. Abbildung 1 zeigt eine beispielhafte P-Q-Wolke. Um die P-Q-Wolken verschiedener MS-Netze vergleichbar zu machen, wurden die P- und Q-Werte auf die jeweilige Bemessungsleistung der versorgenden Umspannwerktransformatoren (UWT) normiert (diese betr{\"a}gt einheitlich 40 MVA). Die P-Q-Wolke besteht dabei aus allen ¼-h-Messwerten der Summenlast am UWT innerhalb eines Jahres. Als Linien angedeutet sind beispielhaft zul{\"a}ssige cosφ-Grenzen je Quadrant.}, language = {de} } @techreport{BruecklEllerHableretal., author = {Br{\"u}ckl, Oliver and Eller, Johannes and Habler, Florian and Sator, Tobias and Sippenauer, Thomas and Strohmayer, Bernhard and Stuber, Johannes}, title = {Zuk{\"u}nftige Bereitstellung von Blindleistung und anderen Maßnahmen f{\"u}r die Netzsicherheit : Endbericht zum Dienstleistungsauftrag}, pages = {210}, abstract = {Der Zweck dieser Studie liegt darin, aufzuzeigen, welche neuen Herausforderungen f{\"u}r den sicheren Netzbetrieb durch den Ausbau der erneuerbaren Energien entstehen und wie diesen zu begegnen ist. Dabei sind praxisnahe Handlungsempfehlungen abzuleiten und Vorschl{\"a}ge f{\"u}r erforderliche Anpassungen zu unterbreiten. Gegenstand der Be-trachtungen sind die - Blindleistung, - Kurzschlussleistung, - Momentanreserve und der - Netzwiederaufbau. Im Fokus dieser Betrachtungen steht allerdings die Bereitstellung der Blindleistung. Konkret soll diese Studie dazu folgende drei Leitfragen beantworten: - Werden die Potenziale der vorhandenen Technologien schon heute kosteneffi-zient genutzt? - L{\"a}sst sich mehr Kosteneffizienz durch eine transparentere und mehr marktge-st{\"u}tzte Beschaffung erzielen? - Welche Anreize w{\"a}ren zu setzen, um die notwendige Mindesterzeugung konven-tioneller Kraftwerke zu reduzieren. Alle drei Leitfragen m{\"u}nden letztlich in der {\"u}bergeordneten Zielsetzung, eine h{\"o}chst-m{\"o}gliche Kosteneffizienz bei der Bereitstellung von SDL zu erlangen.}, language = {de} } @inproceedings{HinterreiterRauchBrueckl, author = {Hinterreiter, Marion and Rauch, Johannes and Br{\"u}ckl, Oliver}, title = {Long-term reactive power forecasting power grids - Challenges and methodologies}, series = {Applied Research Conference - ARC 04.07.2025, Augsburg}, booktitle = {Applied Research Conference - ARC 04.07.2025, Augsburg}, pages = {6}, abstract = {The transition of power systems from fossil fuels to renewable energy sources is driving profound changes across all voltage levels of the electrical grid, altering active power (P) as well as reactive power (Q) behavior. This transformation involves a shift from predominantly top-down, unidirectional electricity flows to bidirectional and increasingly complex flow patterns, fundamentally altering the operation and utilization of power systems. The growing integration of distributed energy resources (DERs), heat pumps (HPs), and electric vehicles (EVs) is particularly impacting lower voltage levels, which are evolving from traditionally consumer-dominated networks into active participants in energy dynamics. These developments have a significant influence on reactive power behavior, with many countries already reporting notable changes due to increased Q contributions from lower voltage levels. As bidirectional flows and decentralized generation increase, understanding and forecasting reactive power trends at these voltage levels becomes essential for ensuring grid stability and efficiency. This paper addresses the challenges of long-term Q forecasting in general by analyzing reactive power behavior in grids, the main influencing grid parameters and introducing existing approaches and concepts, analyzing their applicability, and discussing the associated challenges and methodologies. By shedding light on this underexplored area, the study aims to contribute to the development of advanced long-term reactive power forecasting methods and highlighting research trends.}, language = {en} } @techreport{BruecklEllerAdeltetal., author = {Br{\"u}ckl, Oliver and Eller, Johannes and Adelt, Christian and Gschossmann, David and Kraus, Hermann and Rauch, Johannes and Sippenauer, Thomas and Susewind, Andreas and Wildfeuer, Matthias}, title = {Zuk{\"u}nftige Beschaffung von Blindleistung II : Endbericht zum Dienstleistungsauftrag}, pages = {143}, abstract = {Die vorliegende Studie befasst sich mit der Ermittlung des Bedarfs an Blindleistung f{\"u}r das gesamte deutsche Stromnetz auf Grundlage des NEP 2030 (2019) bis zum Jahr 2035. Die Verteilungsnetze werden dabei in ihrem Blindleistungsverhalten m{\"o}glichst realit{\"a}tsnah nachgebildet. Neben Maßnahmen zur Senkung des Blindleistungsbedarfs werden M{\"o}glichkeiten zur effizienten Deckung aufgezeigt. Dar{\"u}ber hinaus werden die mit der Blindleistungsbereitstellung verbundenen Kosten sowie die Methodik der Be-darfsermittlung beleuchtet.}, language = {de} } @techreport{EichnerGrabKoeppeetal., author = {Eichner, Stefan and Grab, Robin and K{\"o}ppe, Hartmudt and Rauch, Johannes and Schuster, Merten and Scharz, Stefan and Schweiberer, Philipp}, title = {Q-Integral - aktives Blindleistungsmanagement mit dynamischen Blindleistungsquellen an der Schnittstelle Verteilungsnetz und {\"U}bertragungsnetz : Schlussbericht zum Verbundvorhaben : Berichtsdatum: 01.04.2019-30.09.2022}, address = {Braunschweig}, doi = {10.2314/KXP:1882070593}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-89308}, pages = {268}, abstract = {Im Zuge der Energiewende m{\"u}ssen bestehende Konzepte des Netzbetriebs und der Netzplanung angepasst und neue entwickelt werden. Mit steigender Anzahl dezentraler Erzeugungsanlagen im Verteilungsnetz nimmt dort das Potenzial zur Blindleistungs- Bereitstellung zu. Unterdessen werden durch den Wegfall von Großkraftwerken auf der H{\"o}SEbene Blindleistungsquellen vom Netz genommen, w{\"a}hrend die Blindleistungsbedarfe durch steigende Blindleistungsanforderungen - insbesondere in der H{\"o}S-Ebene - weiter steigen. Unter volkswirtschaftlichen Gesichtspunkten und zur Wahrung der Systemstabilit{\"a}t muss daher k{\"u}nftig mehr Blindleistung aus dem Verteilungsnetz bereitgestellt werden. In Q-Integral wurden diese Herausforderungen angenommen und der Themenkomplex des Blindleistungsmanagements ganzheitlich betrachtet. Im vorliegenden Schlussbericht werden die geleisteten Forschungsarbeiten dargestellt.}, language = {de} } @article{Sippenauer, author = {Sippenauer, Thomas}, title = {Bayerische Regionalkonferenz an der OTH Regensburg}, series = {SPEKTRUM}, journal = {SPEKTRUM}, number = {2}, address = {Regensburg}, pages = {29 -- 29}, abstract = {Kann ein flexibilisierter Einsatz der Stromverbraucher zur Netzentlastung in kritischen Zeitpunkten beitragen und wie ist der aktuell h{\"a}ufig genannte Begriff des „zellul{\"a}ren Ansatzes" in diesem Zusammenhang zu verstehen? Am 21. September 2018 waren zahlreiche Partner des Projektes C/sells sowie Vertreterinnen und Vertreter von Umweltschutzorganisationen und aus der Politik an der OTH Regensburg zu Gast, um diesen Fragen nachzugehen und mit Experten zu diskutieren.}, language = {de} } @article{BruecklMayer, author = {Br{\"u}ckl, Oliver and Mayer, Ulrike}, title = {Neues Forschungsprojekt f{\"u}r Biogasanlagen gestartet}, series = {SPEKTRUM}, journal = {SPEKTRUM}, number = {2}, publisher = {Spektrum}, address = {Regensburg}, pages = {35 -- 35}, abstract = {Wie k{\"o}nnen Biogasanlagen nach dem Auslaufen des EEG noch wirtschaftlich betrieben werden? Mit dieser Frage, der Untersuchung der Potenziale und Entwicklung eines Optimierungsmodells f{\"u}r Biogasanlagen im Kontext des zuk{\"u}nftigen Stromsystems besch{\"a}ftigt sich seit September 2018 ein interdisziplin{\"a}res Forscherteam der OTH Regensburg, der OTH Amberg-Weiden und des Instituts f{\"u}r Energietechnik IfE GmbH im Rahmen des Projekts OPTIBIOSY.}, language = {de} } @techreport{BruecklBreySchaechingeretal., author = {Br{\"u}ckl, Oliver and Brey, Ludwig and Sch{\"a}chinger, Johannes and Henneke, Markus and Eigenstetter, Florian and Vogel, Carolin and Ufkes, Antja}, title = {Netzst{\"u}tzung und Systemdienstleistungserbringung durch eine Industriezelle mit Inselnetzf{\"a}higkeit und Erneuerbaren Energien : Schlussbericht zum Verbundvorhaben: INZELL : Projektlaufzeit: 01.06.2020-31.12.2023}, address = {Regensburg}, doi = {10.2314/KXP:1928854451}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-89261}, pages = {XXII, 316}, abstract = {Infolge der Verdr{\"a}ngung von konventionellen Großkraftwerken im Kontext nationaler Klimaschutzbem{\"u}-hungen entstehen offene Flanken im Bereich der Systemsicherheit. Um weiterhin eine hohe Qualit{\"a}t, Zuverl{\"a}ssigkeit und Sicherheit bei der Strom{\"u}bertragung und -verteilung zu gew{\"a}hrleisten, m{\"u}ssen ins-besondere: • bei der Bereitstellung von Blindleistung im {\"U}bertragungsnetz, wo trotz Zunahme der Vorhaltung steigende Defizite im Blindleistungshaushalt f{\"u}r die Zukunft vorhergesagt werden [1], • der Momentanreserve, die nicht mehr systemimmanent in vielen Erzeugungs- und Bezugsanla-gen vorhanden ist und • dem Netzwiederaufbau (NWA), der bislang mittels Großkraftwerke geplant ist, neue Maßnahmen zum Schließen der L{\"u}cken gefunden werden. Aufgrund zunehmend kostensensitiver Fertigungsprozesse bei deutschen Industriebetrieben besteht die Anforderung an eine hohe Zuverl{\"a}ssigkeit der Stromversorgung. Da sowohl l{\"a}nger andauernde Versor-gungsausf{\"a}lle als auch Spannungseinbr{\"u}che des {\"o}ffentlichen Versorgungsnetzes zu hohen Kosten durch Produktionsstillstand und Sch{\"a}den f{\"u}hren k{\"o}nnen, wird auch der Aspekt der Eigenabsicherung bzw. der h{\"o}heren Versorgungsqualit{\"a}t bedeutender. Des Weiteren sind speziell energieintensive Industrieunter-nehmen gefordert, die zum Teil bisweilen bereits bestehende Eigenerzeugung weiter auszubauen und Flexibilit{\"a}ten zu erschließen, um unabh{\"a}ngiger von hohen Strombezugskosten zu sein.}, language = {de} }