Publikationsserver der Ostbayerischen Technischen Hochschule Regensburg
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Transient surrogate modeling of modally reduced structures with discontinuous loads and damping
No full textIn this work, a surrogate model for structural, transient and discontinuously excited finite element method simulations is developed. This allows to reduce the computational effort of repeated calculations of identical models under different load cases. The architecture of the surrogate combines fully connected neural network layers with long short-term memory layers. For the reproduction of different damping ratios, a categorical variable is added to the continuous input data. Based on a recursive flow of the predicted data back to the input layer, long-term dependencies do not vanish due to short-input sequences. The system dimension is reduced by applying the model-order reduction technique for modal decomposition. The high accuracy of the surrogate and the reduction of computational costs are shown on an academic example of a cantilever beam and a real-world example of a robot. The advantages of our approach are illustrated in comparison with state-of-the-art surrogates for transient finite element analysis. By using the surrogate proposed in this study, oscillations due to discontinuous excitation of mechanical structures can be reproduced. For this purpose, only short-input sequences are necessary since the excitation of the oscillations does not have to be part of the input sequence during the whole duration of the oscillations. Due to the categorical variable for the damping ratio, the surrogate can account for the influence of different damping in parameter studies
Technologies for Evaluation of Pelvic Floor Functionality: A Systematic Review
No full textPelvic floor dysfunction is a common problem in women and has a negative impact ontheir quality of life. The aim of this review was to provide a general overview of the current state oftechnology used to assess pelvic floor functionality. It also provides literature research of the phys-iological and anatomical factors that correlate with pelvic floor health. The systematic review wasconducted according to the PRISMA guidelines. PubMed, ScienceDirect, Cochrane Library andIEEE databases were searched for publications on sensor technology for the assessment of pelvicfloor functionality. Anatomical and physiological parameters were identified through a manualsearch. In the systematic review 115 publications were included. 12 different sensor technologieswere identified. Information on the obtained parameters, sensor position, test activities and subjectcharacteristics were prepared in tabular form from each publication. 16 anatomical and physiologi- cal parameters influencing pelvic floor health were identified in 17 published studies and rankedfor their statistical significance. Taken together, this review could serve as a basis for the develop-ment of novel sensors which could allow for quantifiable prevention and diagnosis, as well as par-ticularized documentation of rehabilitation processes related to pelvic floor dysfunctions
Diagnostische Genauigkeit und klinische Anwendungen tragbarer Bewegungssensoren für die Kniegelenksrehabilitation
No full textOperational wear behaviour of 3D-printed lightweight metal gears: EDS and oil analysis comparison
No full textAdditive manufacturing (AM) has come to the fore in recent years among manufacturing techniques. This technique, which has different advantages than traditional ones such as casting, forging and machining, is expected to be widely used in producing machine parts like gears in the coming years. Therefore, experimental data on AM parameters for lightweight metal gears are important for industrial production. In this study, a wear test was applied to AlSi10Mg and Ti6Al4V gears under operational conditions, and the wear behaviour of conventionally and additively manufactured gears was compared. The amount of abrasion elements was determined by analysing the oil in the gearbox. In addition, gear surfaces were analysed using scanning electron microscopy and an energy-dispersive spectrometer before and after wear. Thus, the wear behaviour of gears produced by conventional and AM under service conditions was demonstrated comparatively
Enhancing Decision-Making for Human-Centered Construction Robotics: A Methodological Framework
No full textWhile the Architecture, Engineering, and Construction (AEC) industry is increasingly aware of the rising demands for productivity and human-centered construction improvements, the holistic adoption of robotics as a fundamental strategy to address these challenges has not yet reached comprehensive fruition. This paper therefore introduces a methodological framework aiming to address the industry's pressing need for a systematic approach for assessing the feasibility of integrating robotics into human-centered construction processes. It aims to enhance decision-making regarding the degree of automation in human-centered construction processes, ranging from partial to full robotization or non-robotization. The framework is characterized by a more holistic end-to-end data-/workflow and therefore adopts a multifaceted approach, leveraging BIM-based planning methodologies and integrating new technologies [e.g., Motion Capturing (MoCap), work process simulation software incorporating Digital Human Models (DHM), self-developed conversion/interfacing software and more] that have not been widely used in the industry to date. Subsequently, the framework is evaluated in a real-life bricklaying construction process to ensure a more application-based approach. Overall, the framework advances current construction processes with a more inclusive and conscious technology infill to empower construction professionals with the workflow and corresponding tools necessary for the practical integration of robotics into human-centered construction processes
From Ray Tracing to Channel Impulse Responses: A Review on the Description of Polarimetric Time-Invariant SISO Channels
No full textOne key enabler of autonomous driving is vehicle-to-everything (V2X) communication and positioning using cellular technologies. To design a vehicular localization system, the understanding and modeling of the physical radio channel (RC) is crucial. Polarization is an important yet often overlooked parameter of the RC. The combined polarization of the transmitting and receiving antennas, along with the environment, significantly affects the Channel Impulse Response (CIR) and localization performance. This paper aims to provide a deterministic description of the time-invariant Single-Input Single-Output (SISO) RC with focus on its polarimetric properties. The aim is to link the understanding of physical wave propagation directly to the conventional CIR descriptions used in localization and signal processing. The focus is on SISO RC modeling for arbitrary antennas, including Line-of-Sight (LoS) and multiple reflections. This study intentionally excludes diffraction, diffuse scattering, and bandwidth limitations, yet establishes a foundational frame-work for future multi-antenna systems with full polarimetric capabilities. The paper describes wave propagation using the Jones Calculus to separate polarimetric wave components, and models the polarimetric reception typical of RC modeling methods in positioning. This approach allows for the calculation of received signal at the antenna feed point. The application context of this research is in ranging or positioning within the V2X framework
On Eye Tracking in Software Engineering
No full textEye 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
Basic Investigations on a Compliant 2D Tensegrity Grid for the Use in Soft Robotic Applications
No full textThe use of compliant tensegrity grids in soft robotic applications is a promising research topic. By using these grids, systems with large shape and stiffness change ability can be realized. In this paper, different tensegrity grid variants, consisting of rigid members indirectly connected via compliant tensioned members, are presented. A selected grid variant is analyzed in more detail for shape adaptation. Therefore the use of the grid as end effector in form-fit grippers is selected as a specific application case. Covariance Matrix Adaptation Evolution Strategies are used to optimize actuators for two given shape function variants and an evaluation is carried out
GLOBE Tabletop - Capability Development through Pre-Exercise Learning for Humanitarian Missions
No full textSimulation exercises play a significant role in training for humanitarian missions and provide suitable space for appropriate preparation of humanitarian personnel. It was observed that participants in the GLOBE simulation, a humanitarian crisis simulation exercise, lacked fundamental knowledge concerning structure and process organization, situational awareness, and complex planning tasks. Thus, this paper explores the concept of capability development through pre-exercise learning, suggests improvements of the efficacy and effectiveness of learning for individuals engaged in humanitarian mission simulations, and provides implications for improving the overall effectiveness and outcomes of simulation exercises. The conceptualization of pre-exercise learning with gamification and tabletop exercise elements prior to participation in the simulation exercise is expected to lead to enhanced capability development during the simulation of humanitarian missions