@inproceedings{MichaelValenciaUsmeAbke2025, author = {Michael, M{\"u}nch and Valencia Usme, Yeimy Paola and Abke, J{\"o}rg}, title = {Prototypical Implementation of a Domain Model for an Adaptive Learning System}, series = {Proceedings of the 6th European Conference on Software Engineering Education}, volume = {2025}, booktitle = {Proceedings of the 6th European Conference on Software Engineering Education}, number = {ECSEE '25: Proceedings of the 6th European Conference on Software Engineering Education}, editor = {Mottok, J{\"u}rgen and Hagel, Georg}, doi = {https://dl.acm.org/doi/pdf/10.1145/3723010.3723030}, pages = {190 -- 194}, year = {2025}, abstract = {The goal of this paper is to present the concept and implementation of a Domain Model for an adaptive learning system (ALS) as a defined framework. The ALS is developed in a research setting. In this study, a proposition for a Domain Model based on Experience API (xAPI) protocol within a Learning Record Store (LRS) is outlined. The target is to collect and analyze student data using xAPI statements, such as average working time and learning elements (LEs) interacted with, in order to gain insights into student behavior and learning processes. The aim of this study is to develop and provide a conceptual model using xAPI and LRS in an ALS setting, an architecture that improves the flexibility of developing adaptive learning systems, enabling the creation of personalized learning experiences for a wide range of users and use cases. The combination of xAPI and LRS allows the definition of a precise Domain Model and provides contextualized and structured data. Moreover, xAPI enables the transformation of the inherent complexity of the Domain Model into something understandable and actionable, facilitating deeper analysis of learning experiences. This paper demonstrates how the proposed Domain Model can effectively represent student activities, interactions, and learning outcomes within a defined framework. The expectation is that diverse types of learners, as well as developers and researchers in educational technologies, will benefit from the use of the Domain Model in a learning environment. Here the learner's preferences are diagnosed, and then user interfaces are customized in an adaptive manner to accommodate the preferences. The main task of the Domain Model is to provide data for the adaptive components of the adaptive learning system.}, subject = {Computerunterst{\"u}tztes Lernen}, language = {en} } @inproceedings{NeumaierProbstWoelfeletal.2025, author = {Neumaier, Marcel and Probst, Anne-Catherine and W{\"o}lfel, Maximilian and Bochtler, Ulrich}, title = {Performance Analysis in a Digital TETRA-Simulcast System}, series = {2025 16th German Microwave Conference (GeMiC)}, booktitle = {2025 16th German Microwave Conference (GeMiC)}, year = {2025}, abstract = {In radio communication of mission-critical services, resilient solutions are strongly required to account for public safety. Additionally to the cellular network based on the professional mobile radio European standard TETRA, a digital TETRA-simulcast system is proposed as a redundant network to ensure area coverage in case of base station failure caused e.g. by disasters. This paper presents a preliminary study about network planning of a frequency-efficient digital TETRA-simulcast system to be physically deployed in a hilly region of Germany. Coverage as well as ray tracing analysis and channel modeling were performed by simulations and prove to be helpful tools for the systematic optimization of system performances, especially with regard to the control of intersymbol interference in overlapping zones.}, subject = {TETRA, Telekommunikation}, language = {en} } @inproceedings{MannDoehringStollenwerketal.2022, author = {Mann, Michael and D{\"o}hring, Thorsten and Stollenwerk, Manfred and Wenzler, Sebastian and Pribulla, Theodor and Komž{\´i}k, Richard M. and Sivanic, Peter}, title = {On the importance of the electrical grid power quality for astronomical observatories}, series = {Proceedings of SPIE: Observatory Operations: Strategies, Processes, and Systems IX}, booktitle = {Proceedings of SPIE: Observatory Operations: Strategies, Processes, and Systems IX}, editor = {Benn, Chris R. and Seaman, Robert L. and Adler, David S.}, publisher = {SPIE}, doi = {http://dx.doi.org/10.1117/12.2627227}, year = {2022}, subject = {Elektrizit{\"a}tsversorgung}, language = {en} } @inproceedings{SchoppelHaugManzetal.2025, author = {Schoppel, Paul and Haug, Jim and Manz, Julian and Bigler, Dimitri and Hock, Isabell and Abke, J{\"o}rg and Hagel, Georg}, title = {METHODICAL APPROACH FOR ANALYZING LEARNING PATH FITNESS IN AN AI-BASED ADAPTIVE LEARNING SYSTEM}, series = {EDULEARN Proceedings}, volume = {1}, booktitle = {EDULEARN Proceedings}, publisher = {IATED}, isbn = {978-84-09-74218-9}, issn = {2340-1117}, doi = {https://doi.org/10.21125/edulearn.2025.2430}, pages = {9438 -- 9446}, year = {2025}, abstract = {Learning paths are a cornerstone of many adaptive learning systems, particularly those focusing on adaptive navigational techniques. Evaluating and analyzing these paths is therefore crucial to ensure they effectively support both learners and instructors. For eLearning this process must be highly scalable despite minimal oversight and little to no control over learners' behavior. Consequently, learning path evaluation should be automated, user-friendly, and precise. However, current research on this topic often emphasizes simulations, performance metrics, or mathematical models, without fully considering the broader, learner-centered aspects necessary for meaningful adaptation. The authors prior findings also indicate that approaches to assessing the suitability of learning paths must be optimized. To address these gaps, this paper presents a potential methodological approach for comprehensive learning path evaluation, aiming to enhance both the precision of adaptive learning systems and the overall learning experience. Three different algorithms, derived from learning style tendencies and a lecturer recommendation, were analyzed as an illustrative example, although the method itself is not constrained by the form or data basis of these algorithms. The adaptive learning system utilizes various measures to gauge the suitability of a learning path, all gathered through real-time learner feedback. These measures include the correlation between students' preferred path and each algorithm, referred to as it's fitness, the alignment between students' actual adherence to a generated path and their own perception of their study behavior as well as their satisfaction with the path, and the connection between algorithm fitness and both actual performance and perceived performance. To collect data, students were asked to create their own preferred learning paths by digitally arranging the provided learning elements after receiving an introduction to the respective categories. Once they had completed a topic with a generated learning path, they rated their satisfaction with it and indicated whether they had followed its sequence. They also estimated whether their knowledge level had changed. Learning analytics were then employed to compare these self-reports with students' actual study behavior. Performance was measured using a rating system, while Spearman's Rho and Kendall's Tau served as the main correlation metrics for data analysis. The results indicate that all three algorithms produce paths more closely aligned with students' preferred learning paths than the lecturer recommendation, although no single algorithm demonstrated clear dominance. Student satisfaction showed some correlation with the fitness of the generated learning path. Additionally, student ratings appeared to have a slight positive correlation with learning path fitness, whereas self-perceived performance showed no discernible difference. Analysis of the link between actual student behavior and their feedback suggested that students were not reliable in judging whether or not they had followed a learning path. These findings are consistent with the authors earlier work suggesting the potential effectiveness of the learning path algorithms examined, thus supporting this new methodological approach to analyzing learning paths. The study also provided valuable insights for further development; however, its limited sample size remains a challenge for validation.}, subject = {E-Learning}, language = {en} } @book{Borgeest2024, author = {Borgeest, Kai}, title = {Manipulation of Exhaust Gas Values}, publisher = {Springer Vieweg}, address = {Wiesbaden}, isbn = {978-3-658-45863-8}, doi = {10.1007/978-3-658-45864-5}, pages = {128}, year = {2024}, abstract = {This booklet presents background information on the exhaust gas scandal, e. g. pollutants, engine control units, exhaust gas recirculation, exhaust gas aftertreatment, which driving cycles are used for testing, how manipulations on the test bench are possible and in which legal and political environment this happened unnoticed. Measures are presented, how vehicles can comply with legal limits and how manipulations can be prevented legally and politically in future.}, subject = {Kraftfahrzeug}, language = {en} } @inproceedings{BuedelKuhlmannTeigelkoetter2024, author = {B{\"u}del, Johannes and Kuhlmann, Kai and Teigelk{\"o}tter, Johannes}, title = {Improved DC-Charging for Traction Drives with Hybrid Powered Dual Two-Level Inverter}, series = {2023 25th European Conference on Power Electronics and Applications (EPE'23 ECCE Europe)}, booktitle = {2023 25th European Conference on Power Electronics and Applications (EPE'23 ECCE Europe)}, doi = {10.23919/EPE23ECCEEurope58414.2023.10264409}, year = {2024}, abstract = {This contribution aims to present a new concept for power sharing of traction drives supplied by local DC grids such as partly or full equipped trolley wire nets. Therefore, a dual two-level inverter with two separate energy storages and an open-end winding machine is used. New control algorithms allow the charging of the energy sources whether two batteries, a combination of a battery and a fuel cell or a combination of battery and a flying capacitor is used. Within the scope of battery performance, this application is able to absorb or deliver the required power from a DC grid and still feed the electrical machine to enable a driving movement of the electric vehicle. As the presented concepts enable voltage balancing due to different battery loads and the use of only one dynamic energy storage in the charging operation, the shown application aims to achieve the high utilization of an electric vehicle powered by a (partly equipped) DC-grid.}, subject = {Wechselrichter}, language = {en} } @inproceedings{FischerHaugSchoppeletal.2025, author = {Fischer, David Vincent and Haug, Jim and Schoppel, Paul and Abke, J{\"o}rg and Becker, Matthias and Hagel, Georg}, title = {Evaluation of a Node-based Automatic Short Answer Tool "NodeGrade"}, series = {Proceedings of the 6th European Conference on Software Engineering Education}, booktitle = {Proceedings of the 6th European Conference on Software Engineering Education}, publisher = {ACM}, address = {New York, NY, USA}, doi = {https://dl.acm.org/doi/10.1145/3723010.3723021}, pages = {20 -- 29}, year = {2025}, abstract = {NodeGrade tries to provide a suitable solution for the problem of time-intensive short answer grading. This research focuses simultaneously on performance, functionality and user experience, which is underlined by a triangulated approach. The evaluation results show comparable performance of NodeGrade on public datasets, even outperforming GPT-4 on the SemEval 2013 Task 7. Matching of NodeGrade's output with multiple human expert raters reveals some weaknesses regarding cases at the lower and upper boundary. In terms of user experience, the interviewed and observed students recognized both positive facets, like better learning support and helpful feedback, and negative sides, including technical limitations and lack of transparency. Overall, NodeGrade promises high potential for further practical use and testing in the field of software engineering education and automatic short answer grading.}, subject = {Software Engineering}, language = {en} } @inproceedings{HockHaugAbke2025, author = {Hock, Isabell and Haug, Jim and Abke, J{\"o}rg}, title = {DIDACTIC INTEGRATION OF SELF-STUDY AND FACE-TO-FACE TEACHING: EXPERIENCES WITH AN ADAPTIVE LEARNING SYSTEM IN ENGINEERING EDUCATION}, series = {ICERI Proceedings}, volume = {1}, booktitle = {ICERI Proceedings}, publisher = {IATED}, isbn = {978-84-09-78706-7}, issn = {2340-1095}, doi = {https://doi.org/10.21125/iceri.2025.1600}, pages = {5825 -- 5829}, year = {2025}, abstract = {This paper presents a study of student perspectives on the didactic integration of digital learning elements into face-to-face university lectures and seminars. The overarching context is the use of the adaptive learning system (ALS) HASKI (short for Hochschullehre: Adaptiv, selbstgesteuert, KI-gest{\"u}tzt, i.e. Higher Education: Adaptive, Self-Directed, AI-Supported), which was tested in computer science teaching within a blended learning approach, more specifically in flipped classroom scenarios. The joint project, consisting of three Bavarian universities, focuses on the exploratory integration of an AI-based ALS into higher education. The system was applied in a course for mechatronics students (2nd semester) and provided a variety of adaptive learning elements. HASKI generates individual learning paths with AI based on learning behavior and learning styles. It is designed to promote personalized, self-directed learning as support for blended learning scenarios. The method chosen for data collection is a qualitative content analysis based on exploratory interviews with a semi-structured set of questions. Four central analysis criteria were considered: acceptance and perception of the learning elements, integration into lectures and exercise sessions, didactic coherence, and suggestions for improvement. The results show that students prefer explanatory scripts, interactive tasks, and quiz elements that require a certain degree of reflection. In addition, the respondents are largely convinced of the integration into the seminar, as the HASKI system adequately guides them for what to prepare for. When it comes to embedding the system into lectures, especially in the form of question rotation in small groups, the feedback is ambivalent. Although the potential for in-depth learning was recognized, the low participation of fellow students was critically reflected upon. A particular difficulty mentioned was the lack of coordination between self-study and classroom attendance. While some participants saw this as a discrepancy of coherence, others viewed the adaptive system as a balancing factor. There was a desire for a clearer time structure and more in-depth materials that go beyond mere repetition. Overall, the findings provide initial indicators of successful aspects in the integration of adaptive systems into classroom teaching. The continuous development of a clear didactic division of roles between self-study and classroom phases is of central importance here. Further research with larger samples, if necessary, could provide more comprehensive insights.}, subject = {E-Learning}, language = {en} } @inproceedings{GirvanStolteMann2020, author = {Girvan, Philipp and Stolte, Andreas and Mann, Michael}, title = {Conceptualising Different Approaches to the New Redispatch Procedure in Germany with Special Regard to the Distribution of Competences among the Grid Operators}, publisher = {IEEE}, organization = {IEEE}, isbn = {9783800753383}, year = {2020}, abstract = {P. Girvan, A. Stolte and M. Mann, "Conceptualising Different Approaches to the New Redispatch Procedure in Germany with Special Regard to the Distribution of Competences among the Grid Operators," PESS 2020; IEEE Power and Energy Student Summit, Online, 2020, pp. 1-6. New regulations in Germany bring forth the question how a new Redispatch procedure can better integrate renewable energies into the congestion management. These changes fall back to the amendment of the German law on power line expansion from Mai 2019 [1]. This debate got picked up by the German Association of Energy in 2019 [2]. Since then Redispatch 2.0 has become a major topic for grid operators, especially for the DSO which will see major impacts on the congestion management. Redispatch describes the process of resolving grid congestion by adjusting the schedule of conventional power plants. With a high amount of renewables on their grid Germany has seen a drastic increase in grid congestion and the resulting costs [3]. For that reason, the government decided to adapt the Redispatch process and in- clude renewable energy power plants into it. While this new approach promises to resolve some of the costly problems with the current Redispatch, it also introduces a big challenge to the grid operators. This calls for a new approach to the distribution of competencies among the grid operators. With this need in mind, three different possible concepts for the new Redispatch are developed and evaluated within three unique scenarios. This evaluation shows that a concept, which focuses on a Redispatch lead by the TSO, is most adapt for the new requirements. This result is picked up in the recommendation of action, where further research is encouraged.}, subject = {Elektrizit{\"a}tsversorgungsnetz}, language = {de} } @inproceedings{ManzAbkeHagel2025, author = {Manz, Julian and Abke, J{\"o}rg and Hagel, Georg}, title = {Automated Tracking of User Interactions in Web-Based Adaptive Learning for Software Engineering}, series = {ECSEE '25: Proceedings of the 6th European Conference on Software Engineering Education}, booktitle = {ECSEE '25: Proceedings of the 6th European Conference on Software Engineering Education}, editor = {Mottok, J{\"u}rgen and Hagel, Georg}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, isbn = {979-8-4007-1282-1}, doi = {10.1145/3723010.3723020}, pages = {180 -- 184}, year = {2025}, abstract = {This paper explores the automation of generating and dispatching Experience API (xAPI) statements for comprehensive tracking of user interactions in e-learning environments. It introduces the react-xapi-wrapper library, an extension of the xAPI JavaScript library designed for use in web applications. Key aspects discussed include the library's features, its integration into a web-based adaptive learning system (ALS) for software engineering, and the custom verbs used. The goal is to reduce implementation effort for tutors and developers while taking advantage of xAPI's interoperability, scalability, and ability to track student learning activities and behaviors, laying the foundation for more responsive and personalized learning experiences.}, subject = {Computerunterst{\"u}tztes Lernen}, language = {en} } @inproceedings{BuedelHerkommerKuhlmannetal.2021, author = {B{\"u}del, Johannes and Herkommer, Christian and Kuhlmann, Kai and Teigelk{\"o}tter, Johannes}, title = {Advanced DC-charging Methods for Traction Drives with Dual Two-Level Inverter During Machine Operation}, series = {2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe)}, booktitle = {2021 23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe)}, doi = {10.23919/EPE21ECCEEurope50061.2021.9570611}, year = {2021}, abstract = {This paper aims to present a concept and especially developed control methods for an open-end winding traction drive, powered by a dual two-level inverter, where the two separate energy sources can be charged via a DC grid during operation and while being standstill. For achieving a high quality DC-current, the parasitic Back-EMF harmonics of the electrical machine will be compensated. The application aims to achieve high utilisation of the electric vehicle in combination with a partly equipped trolley wire net.}, subject = {Wechselrichter}, language = {en} } @inproceedings{NormannHaugValenciaetal.2023, author = {Normann, Marc and Haug, Jim and Valencia, Yeimy and Abke, J{\"o}rg and Hagel, Georg}, title = {Adaptive Learning Path Sequencing Based on Learning Styles within N-dimensional Spaces}, series = {ECSEE '23: Proceedings of the 5th European Conference on Software Engineering Education}, volume = {2023}, booktitle = {ECSEE '23: Proceedings of the 5th European Conference on Software Engineering Education}, editor = {Mottock, J{\"u}rgen and Hagel, Georg}, doi = {https://doi.org/10.1145/3593663.3593676}, pages = {56 -- 64}, year = {2023}, abstract = {Planning adaptive learning paths for students' progress throughout a course can be a challenging task, although it can be helpful for their learning progress. Within the HASKI-System, students should be able to get their own, personalized learning paths. In this paper, we present an approach towards the learning path sequencing problem. This idea is based on a novel proposal for arranging learning objects in a multi-dimensional space, bringing the relationship and similarities of these objects into a new relationship. We show, that we can use both, the Ant Colony Optimization Algorithm and the Genetic Algorithm with the idea of the Traveling-Salesman-Problem and get results, that are comparable with a proposed literature-based adaption mechanism. Nevertheless, the learning paths are all personalized based on the Felder \& Silverman Learning Style Model and the hyperspace model will allow us later on to include more dimensions for other influencing factors.}, subject = {Lernstil}, language = {en} } @article{MahtoMahatoChandanetal.2024, author = {Mahto, Kailash Kumar and Mahato, Bidyut and Chandan, Bikramaditya and Das, Durbanjali and Das, Priyanath and Fotis, Georgios and Vita, Vasiliki and Mann, Michael}, title = {A New Symmetrical Source-Based DC/AC Converter with Experimental Verification}, series = {Electronics}, volume = {13}, journal = {Electronics}, number = {10}, publisher = {MDPI AG}, issn = {2079-9292}, doi = {http://dx.doi.org/10.3390/electronics13101975}, year = {2024}, abstract = {This research paper introduces a new topology for multilevel inverters, emphasizing the reduction of harmonic distortion and the optimization of the component count. The complexity of an inverter is determined by the number of power switches, which is significantly reduced in the presented topology, as fewer switches require fewer driver circuits. In this proposed topology, a new single-phase generalized multilevel inverter is analyzed with an equal magnitude of voltage supply. A 9-level, 11-level, or 13-level symmetrical inverter with RL load is analyzed in MATLAB/Simulink 2019b and then experimentally validated using the dSPACE-1103 controller. The experimental verification of the load voltage and current with different modulation indices is also presented. The analysis of the proposed topology concludes that the total required number of components is lower than that necessary for the classical inverter topologies, as well as for some new proposed multilevel inverters that are also compared with the proposed topology in terms of gate driver circuits, power switches, and DC sources, which thereby enhances the goodness of the proposed topology. Thus, a comparison of this inverter with the other topologies validates its acceptance.}, subject = {Spannungswandler}, language = {en} } @article{DasMahatoChandanetal.2024, author = {Das, Durbanjali and Mahato, Bidyut and Chandan, Bikramaditya and Joshi, Hitesh and Mahto, Kailash Kumar and Das, Priyanath and Fotis, Georgios and Vita, Vasiliki and Mann, Michael}, title = {A New Cascaded Multilevel Inverter for Modular Structure and Reduced Passive Components}, series = {Electronics}, volume = {13}, journal = {Electronics}, number = {17}, publisher = {MDPI AG}, issn = {2079-9292}, doi = {http://dx.doi.org/10.3390/electronics13173566}, year = {2024}, abstract = {In high-power applications, achieving adequate power quality in power converter design is accomplished by utilizing multilevel inverters instead of using two-level and three-level inverters. The device generates a sinusoidal output voltage, which results in reduced total harmonic distortion and lower voltage stress on the switches and leads to lower electromagnetic interference, making it suitable for use in renewable energy applications. However, to illustrate the advantages mentioned above, a significant number of switching devices and DC sources are necessary while raising the voltage levels. This article proposes an asymmetrical voltage generation method, which operates in a ratio of 1:5 and generates 25 levels using 11 power switches. The topology is modular in structure, and each module has a lower component count, which significantly reduces the overall cost. The proposed topology is capable of generating negative output voltage levels without the use of an H-bridge configuration, where only three switches are used to generate any voltage levels. The functionality of the developed module is amended by fixing different voltage values in DC sources. This article also presents a comprehensive examination of the circuit and the functioning of various voltage levels. The advantages of the proposed inverter have been demonstrated by comparative research with the currently existing MLI topologies. Ultimately, both the simulation and experimental findings validated the practical capabilities.}, subject = {Mehrpunktwechselrichter}, language = {en} }