TY - CHAP A1 - Altherr, Lena A1 - Döring, Bernd A1 - Frauenrath, Tobias A1 - Groß, Rolf A1 - Mohan, Nijanthan A1 - Oyen, Marc A1 - Schnittcher, Lukas A1 - Voß, Norbert ED - Reiff-Stephan, Jörg ED - Jäkel, Jens ED - Schwarz, André T1 - DiggiTwin: ein interdisziplinäres Projekt zur Nutzung digitaler Zwillinge auf dem Weg zu einem klimaneutralen Gebäudebestand T2 - Tagungsband AALE 2024 : Fit für die Zukunft: praktische Lösungen für die industrielle Automation N2 - Im Hinblick auf die Klimaziele der Bundesrepublik Deutschland konzentriert sich das Projekt Diggi Twin auf die nachhaltige Gebäudeoptimierung. Grundlage für eine ganzheitliche Gebäudeüberwachung und -optimierung bildet dabei die Digitalisierung und Automation im Sinne eines Smart Buildings. Das interdisziplinäre Projekt der FH Aachen hat das Ziel, ein bestehendes Hochschulgebäude und einen Neubau an klimaneutrale Standards anzupassen. Im Rahmen des Projekts werden bekannte Verfahren, wie das Building Information Modeling (BIM), so erweitert, dass ein digitaler Gebäudezwilling entsteht. Dieser kann zur Optimierung des Gebäudebetriebs herangezogen werden, sowie als Basis für eine Erweiterung des Bewertungssystems Nachhaltiges Bauen (BNB) dienen. Mithilfe von Sensortechnologie und künstlicher Intelligenz kann so ein präzises Monitoring wichtiger Gebäudedaten erfolgen, um ungenutzte Energieeinsparpotenziale zu erkennen und zu nutzen. Das Projekt erforscht und setzt methodische Erkenntnisse zu BIM und digitalen Gebäudezwillingen praxisnah um, indem es spezifische Fragen zur Energie- und Ressourceneffizienz von Gebäuden untersucht und konkrete Lösungen für die Gebäudeoptimierung entwickelt. KW - Anomalieerkennung KW - IoT KW - Überwachung & Optimierung KW - DiggiTwin KW - BIM KW - Smart Building KW - Digitalisierung Y1 - 2024 SN - 978-3-910103-02-3 U6 - https://doi.org/10.33968/2024.67 N1 - 20. AALE-Konferenz. Bielefeld, 06.03.-08.03.2024 (Tagungsband unter https://doi.org/10.33968/2024.29) SP - 341 EP - 346 PB - le-tex publishing services GmbH CY - Leipzig ER - TY - JOUR A1 - Zhen, Manghao A1 - Liang, Yunpei A1 - Staat, Manfred A1 - Li, Quanqui A1 - Li, Jianbo T1 - Discontinuous fracture behaviors and constitutive model of sandstone specimens containing non-parallel prefabricated fissures under uniaxial compression JF - Theoretical and Applied Fracture Mechanics N2 - The deformation and damage laws of non-homogeneous irregular structural planes in rocks are the basis for studying the stability of rock engineering. To investigate the damage characteristics of rock containing non-parallel fissures, uniaxial compression tests and numerical simulations were conducted on sandstone specimens containing three non-parallel fissures inclined at 0°, 45° and 90° in this study. The characteristics of crack initiation and crack evolution of fissures with different inclinations were analyzed. A constitutive model for the discontinuous fractures of fissured sandstone was proposed. The results show that the fracture behaviors of fissured sandstone specimens are discontinuous. The stress–strain curves are non-smooth and can be divided into nonlinear crack closure stage, linear elastic stage, plastic stage and brittle failure stage, of which the plastic stage contains discontinuous stress drops. During the uniaxial compression test, the middle or ends of 0° fissures were the first to crack compared to 45° and 90° fissures. The end with small distance between 0° and 45° fissures cracked first, and the end with large distance cracked later. After the final failure, 0° fissures in all specimens were fractured, while 45° and 90° fissures were not necessarily fractured. Numerical simulation results show that the concentration of compressive stress at the tips of 0°, 45° and 90° fissures, as well as the concentration of tensile stress on both sides, decreased with the increase of the inclination angle. A constitutive model for the discontinuous fractures of fissured sandstone specimens was derived by combining the logistic model and damage mechanic theory. This model can well describe the discontinuous drops of stress and agrees well with the whole processes of the stress–strain curves of the fissured sandstone specimens. KW - Constitutive model KW - Damage mechanics theory KW - Discontinuous fractures KW - Uniaxial compression test KW - Non-parallel fissures Y1 - 2024 U6 - https://doi.org/10.1016/j.tafmec.2024.104373 SN - 0167-8442 VL - 131 PB - Elsevier CY - Amsterdam ER - TY - RPRT A1 - Birmans, Katrin A1 - Tambornino, Philipp A1 - Ullrich, Anna Valentine T1 - 5 Gründe für Coscine - Handreichung für Forschende an HAW N2 - Welche Vorteile bietet die Forschungsdatenmanagement-Plattform Coscine für die Verwaltung von Daten in Forschungsprojekten? Hierzu gibt die Handreichung einen schnellen Überblick über den landesgeförderten Dienst Coscine für Forschende und FDM-Service-Personal an HAW in NRW (DH.NRW-Hochschulen). FDM-Service-Mitarbeitende können die Handreichung in ihrer Beratung zu Coscine einsetzen und mit der Eingabemaske in der Kopfzeile des Dokuments auf ihre Hochschule anpassen. Y1 - 2024 U6 - https://doi.org/10.5281/zenodo.12156734 N1 - Die Handreichung ist im Projekt Persist@HAW (FK: 16FDFH129), gefördert vom BMBF, entstanden. ER - TY - JOUR A1 - Clausnitzer, Julian A1 - Kleefeld, Andreas T1 - A spectral Galerkin exponential Euler time-stepping scheme for parabolic SPDEs on two-dimensional domains with a C² boundary JF - Discrete and Continuous Dynamical Systems - Series B N2 - We consider the numerical approximation of second-order semi-linear parabolic stochastic partial differential equations interpreted in the mild sense which we solve on general two-dimensional domains with a C² boundary with homogeneous Dirichlet boundary conditions. The equations are driven by Gaussian additive noise, and several Lipschitz-like conditions are imposed on the nonlinear function. We discretize in space with a spectral Galerkin method and in time using an explicit Euler-like scheme. For irregular shapes, the necessary Dirichlet eigenvalues and eigenfunctions are obtained from a boundary integral equation method. This yields a nonlinear eigenvalue problem, which is discretized using a boundary element collocation method and is solved with the Beyn contour integral algorithm. We present an error analysis as well as numerical results on an exemplary asymmetric shape, and point out limitations of the approach. KW - Nonlinear eigenvalue problems KW - Boundary integral equations, KW - Exponential Euler scheme, KW - Parabolic SPDEs Y1 - 2024 U6 - https://doi.org/10.3934/dcdsb.2023148 SN - 1531-3492 SN - 1553-524X (eISSN) VL - 29 IS - 4 SP - 1624 EP - 1651 PB - AIMS CY - Springfield ER - TY - CHAP A1 - Simsek, Beril A1 - Krause, Hans-Joachim A1 - Engelmann, Ulrich M. ED - Digel, Ilya ED - Staat, Manfred ED - Trzewik, Jürgen ED - Sielemann, Stefanie ED - Erni, Daniel ED - Zylka, Waldemar T1 - Magnetic biosensing with magnetic nanoparticles: Simulative approach to predict signal intensity in frequency mixing magnetic detection T2 - YRA MedTech Symposium (2024) N2 - Magnetic nanoparticles (MNP) are investigated with great interest for biomedical applications in diagnostics (e.g. imaging: magnetic particle imaging (MPI)), therapeutics (e.g. hyperthermia: magnetic fluid hyperthermia (MFH)) and multi-purpose biosensing (e.g. magnetic immunoassays (MIA)). What all of these applications have in common is that they are based on the unique magnetic relaxation mechanisms of MNP in an alternating magnetic field (AMF). While MFH and MPI are currently the most prominent examples of biomedical applications, here we present results on the relatively new biosensing application of frequency mixing magnetic detection (FMMD) from a simulation perspective. In general, we ask how the key parameters of MNP (core size and magnetic anisotropy) affect the FMMD signal: by varying the core size, we investigate the effect of the magnetic volume per MNP; and by changing the effective magnetic anisotropy, we study the MNPs’ flexibility to leave its preferred magnetization direction. From this, we predict the most effective combination of MNP core size and magnetic anisotropy for maximum signal generation. Y1 - 2024 SN - 978-3-940402-65-3 U6 - https://doi.org/10.17185/duepublico/81475 N1 - 4th YRA MedTech Symposium, February 1, 2024. FH Aachen, Campus Jülich SP - 27 EP - 28 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - JOUR A1 - Ayala, Rafael Ceja A1 - Harris, Isaac A1 - Kleefeld, Andreas T1 - Direct sampling method via Landweber iteration for an absorbing scatterer with a conductive boundary JF - Inverse Problems and Imaging N2 - In this paper, we consider the inverse shape problem of recovering isotropic scatterers with a conductive boundary condition. Here, we assume that the measured far-field data is known at a fixed wave number. Motivated by recent work, we study a new direct sampling indicator based on the Landweber iteration and the factorization method. Therefore, we prove the connection between these reconstruction methods. The method studied here falls under the category of qualitative reconstruction methods where an imaging function is used to recover the absorbing scatterer. We prove stability of our new imaging function as well as derive a discrepancy principle for recovering the regularization parameter. The theoretical results are verified with numerical examples to show how the reconstruction performs by the new Landweber direct sampling method. Y1 - 2024 U6 - https://doi.org/10.3934/ipi.2023051 SN - 1930-8337 SN - 1930-8345 (eISSN) VL - 18 IS - 3 SP - 708 EP - 729 PB - AIMS CY - Springfield ER - TY - INPR A1 - Grieger, Niklas A1 - Mehrkanoon, Siamak A1 - Bialonski, Stephan T1 - Preprint: Data-efficient sleep staging with synthetic time series pretraining T2 - arXiv N2 - Analyzing electroencephalographic (EEG) time series can be challenging, especially with deep neural networks, due to the large variability among human subjects and often small datasets. To address these challenges, various strategies, such as self-supervised learning, have been suggested, but they typically rely on extensive empirical datasets. Inspired by recent advances in computer vision, we propose a pretraining task termed "frequency pretraining" to pretrain a neural network for sleep staging by predicting the frequency content of randomly generated synthetic time series. Our experiments demonstrate that our method surpasses fully supervised learning in scenarios with limited data and few subjects, and matches its performance in regimes with many subjects. Furthermore, our results underline the relevance of frequency information for sleep stage scoring, while also demonstrating that deep neural networks utilize information beyond frequencies to enhance sleep staging performance, which is consistent with previous research. We anticipate that our approach will be advantageous across a broad spectrum of applications where EEG data is limited or derived from a small number of subjects, including the domain of brain-computer interfaces. Y1 - 2024 ER - TY - CHAP A1 - Wittig, M. A1 - Rütters, René A1 - Bragard, Michael ED - Reiff-Stephan, Jörg ED - Jäkel, Jens ED - Schwarz, André T1 - Application of RL in control systems using the example of a rotatory inverted pendulum T2 - Tagungsband AALE 2024 : Fit für die Zukunft: praktische Lösungen für die industrielle Automation N2 - In this paper, the use of reinforcement learning (RL) in control systems is investigated using a rotatory inverted pendulum as an example. The control behavior of an RL controller is compared to that of traditional LQR and MPC controllers. This is done by evaluating their behavior under optimal conditions, their disturbance behavior, their robustness and their development process. All the investigated controllers are developed using MATLAB and the Simulink simulation environment and later deployed to a real pendulum model powered by a Raspberry Pi. The RL algorithm used is Proximal Policy Optimization (PPO). The LQR controller exhibits an easy development process, an average to good control behavior and average to good robustness. A linear MPC controller could show excellent results under optimal operating conditions. However, when subjected to disturbances or deviations from the equilibrium point, it showed poor performance and sometimes instable behavior. Employing a nonlinear MPC Controller in real time was not possible due to the high computational effort involved. The RL controller exhibits by far the most versatile and robust control behavior. When operated in the simulation environment, it achieved a high control accuracy. When employed in the real system, however, it only shows average accuracy and a significantly greater performance loss compared to the simulation than the traditional controllers. With MATLAB, it is not yet possible to directly post-train the RL controller on the Raspberry Pi, which is an obstacle to the practical application of RL in a prototyping or teaching setting. Nevertheless, RL in general proves to be a flexible and powerful control method, which is well suited for complex or nonlinear systems where traditional controllers struggle. KW - Rotatory Inverted Pendulum KW - MPC KW - LQR KW - PPO KW - Reinforcement Learning Y1 - 2024 SN - 978-3-910103-02-3 U6 - https://doi.org/10.33968/2024.53 N1 - 20. AALE-Konferenz. Bielefeld, 06.03.-08.03.2024. (Tagungsband unter https://doi.org/10.33968/2024.29) SP - 241 EP - 248 PB - le-tex publishing services GmbH CY - Leipzig ER - TY - PAT A1 - Hüning, Felix T1 - Positionssensorvorrichtung N2 - Die Erfindung betrifft eine Positionssensorvorrichtung zur Bestimmung einer Absolutposition eines beweglichen ersten Teils relativ zu einem ortsfesten zweiten Teil mit einem mit dem beweglichen ersten Teil gekoppelter Codekörper, der dazu eingerichtet ist, eine Codespur mit einer Mehrzahl von in Spurrichtung aufeinanderfolgenden Codeelementen zu enthalten zur Bildung eines Codewortes, mit einer magnetischen Detektionseinrichtung zur Detektion der Codespur, wobei die Detektionseinrichtung zum einen an dem Codekörper befestigte und entlang der Spurrichtung in einem solchen Abstand gegenpolig zueinander angeordnete Permanentmagneten aufweist, dass der Abstand mit einer vorgegebenen Länge der jeweiligen Codeelemente übereinstimmt, und zum anderen eine Anzahl von ortsfest und quer zu dem Codekörper versetzt angeordnete Wiegandsensoren aufweist, wobei der Abstand des Wiegandsensors zu einer Erstreckungsebene der Permanentmagneten derart gewählt ist, dass bei Überdeckung des Wiegandsensors durch den Permanentmagneten ein Wiegandpuls in dem Wiegandsensor induziert wird. Y1 - 2024 ER - TY - CHAP A1 - Kramer, Pia A1 - Bragard, Michael A1 - Ritz, Thomas A1 - Ferfer, Ute A1 - Schiffers, Tim T1 - Visualizing, Enhancing and Predicting Students’ Success through ECTS Monitoring T2 - 2024 IEEE Global Engineering Education Conference (EDUCON) N2 - This paper serves as an introduction to the ECTS monitoring system and its potential applications in higher education. It also emphasizes the potential for ECTS monitoring to become a proactive system, supporting students by predicting academic success and identifying groups of potential dropouts for tailored support services. The use of the nearest neighbor analysis is suggested for improving data analysis and prediction accuracy. KW - Monitoring KW - Engineering education KW - Data visualization KW - Accuracy KW - Data analysis Y1 - 2024 U6 - https://doi.org/10.1109/EDUCON60312.2024.10578652 SN - 2165-9559 SN - 2165-9567 (eISSN) N1 - 2024 IEEE Global Engineering Education Conference (EDUCON), 08-11 May 2024, Kos Island, Greece PB - IEEE CY - New York, NY ER -