TY - CHAP A1 - Simmering, Veronika A1 - Pfeiffer, Thies A1 - Kindsmüller, Martin Christof T1 - The Impact of Embodiment and Output Modality on Learning with Conversational Agents in VR T2 - GI Workshop 2025 on Virtual and Augmented Reality : VR/AR 2025, Lecture Notes in Informatics (LNI), Gesellschaft für Informatik, Bonn 2025 N2 - In Virtual Reality (VR) learning applications, the integration of pedagogical agents is particularly promising, as they function as a virtual social support. With the recent developments in Large Language Models (LLMs), conversational language models are now available that enable natural language interaction in a VR environment. We evaluated four possible designs for LLM-based agents (푛 = 21) in an aircraft-engine training. Focusing on the primary questions when bringing LLM-based agents into VR: whether to use text or speech and whether to embody the conversational agent in 3D or not. Pre- and post-tests were used to measure retention and questionnaires were used to measure the User Experience (UX) of different design variants. Contrary to our hypotheses, retention was higher when using a non-embodied design compared to an embodied design. The output modality did not have a significant impact on the learning success, but it did have an impact on the UX. Y1 - 2025 U6 - https://doi.org/10.18420/vrar2025_12 SN - 2944-7682 SP - 235 EP - 254 PB - Gesellschaft für Informatik ER - TY - CHAP A1 - Querner, Erich A1 - Ewerling, Philipp A1 - Kindsmüller, Martin Christof T1 - Setting the Stage for Collaboration: A Multi-View Table for Touch and Tangible Map Interaction T2 - Mensch und Computer 2025 - Workshopband : MCI-WS11: 18th Workshop “Be-greifbare Interaktion”. Chemnitz. 31. August - 03. September 2025 N2 - We present a multi-user map application based on a novel multiview concept that enables simultaneous and independent interaction with shared geospatial content. Each user operates a personal View Finder and Focus View, color-coded for clarity, while a shared, immutable Context View provides a common reference frame. The system supports both touch-based and tangible interaction techniques, including gesture control, virtual joysticks, and physical objects. Users can flexibly arrange their workspaces on a multi-touch table, supporting both individual exploration and collaborative tasks. Y1 - 2025 U6 - https://doi.org/10.18420/muc2025-mci-demo-318 SP - 1 EP - 4 PB - Gesellschaft für Informatik ER - TY - CHAP A1 - Querner, Erich A1 - Ewerling, Philipp A1 - Kindsmüller, Martin Christof T1 - Touch gets it done, tangibles make it fun? Balancing objective accuracy and user experience T2 - Mensch und Computer 2025 - Workshopband : MCI-WS11: 18th Workshop “Be-greifbare Interaktion”. Chemnitz. 31. August - 03. September 2025 N2 - This study compares Tangible User Interfaces (TUIs) with conventional touch interfaces (CTIs) on multi-touch tables for exploratory multi-user map applications. We developed a prototype that enables multiple users to interact with map content simultaneously and independently. Four interaction methods were implemented and evaluated: gesture-based touch control, widget-based touch joystick control, and two tangible interaction variants (a joystick and car-steering metaphor). A user study with 15 participants was conducted in which users navigated predefined routes with varying difficulty. We collected both objective performance measurements and subjective user assessments. While touch-based methods yielded higher accuracy in objective metrics, TUI-based interactions were rated significantly better by participants in terms of user experience. Notably, the car-steering tangible control was particularly well-received, highlighting how physical, playful interaction can enhance usability despite lower accuracy. These findings contribute to our understanding of how different interaction paradigms support collaborative exploration on multi-touch surfaces. Y1 - 2025 U6 - https://doi.org/https://doi.org/10.18420/muc2025-mci-ws11-164 SP - 1 EP - 6 PB - Gesellschaft für Informatik ER - TY - CHAP A1 - Daupayev, Nursultan A1 - Reber, Paul A1 - Bendyk, Ricky A1 - Engel, Christian A1 - Hirsch, Sören T1 - Data Reduction for Energy-Constrained Sensors via Event-Aware Sampling T2 - Konferenz: 2025 IEEE SENSORS, Vancouver, BC, Canada, 2025 N2 - Environmental monitoring plays a crucial role in analyzing environmental parameters and detecting anomalies. However, sensor systems work continuously, which results in constant energy consumption and data redundancy, especially for sensors with limited computing power and memory. In addition, installing and maintaining sensors in remote places creates additional challenges. An adaptive environmental sensing approach is developed to reduce data redundancy and energy consumption. A custom-designed sensor based on PIC16LF19156 microcontroller measures CO2, humidity and temperature simultaneously. The sensor is connected to a Raspberry Pi, where a signal processing algorithm is executed, aimed at reducing data redundancy, thereby increasing the energy efficiency of the system. The algorithm includes the discrete wavelet transform (DWT) to extract spectral features from the signals. A machine learning model trained on previous data estimates the daily variability of the signal and saves data labeled as SAVE (deviations) or SKIP (consistency). As a result, only the relevant intervals showing significant fluctuations are retained. The effectiveness of the proposed approach was evaluated by reconstructing the compressed signals and comparing them with the original data based on RMSE and MAE metrics, which confirms the insignificant loss of information. Y1 - 2025 SN - 979-8-3315-4467-6 U6 - https://doi.org/10.1109/SENSORS59705.2025.11330656 SN - 2168-9229 SP - 1 EP - 4 PB - IEEE ER - TY - JOUR A1 - Vollmer, Michael T1 - Optical Phenomena in the Atmosphere JF - Encyclopedia of Atmospheric Sciences N2 - Following a brief description of the atmosphere and spectra of the Sun as dominant daytime light source, the most common optical phenomena within the troposphere are discussed, which are due to scattering of radiation with the constituents of the atmosphere. At first mirages, rainbows, coronas, iridescence, glories and halos are explained. Then light scattering phenomena which give rise to sunset colors, blue and colorful skies are presented as well as related phenomena like blue mountains, white clouds, green flashes and visual ranges. The review ends with a short survey of other less easily observable optical phenomena of the atmosphere and a very detailed bibliography. Y1 - 2025 U6 - https://doi.org/10.1016/B978-0-323-96026-7.00177-6 IS - 2 SP - 285 EP - 306 PB - academic press ET - 3 ER - TY - CHAP A1 - Vollmer, Michael T1 - Elektromagnetische Wellen – Grundlagen und ausgewählte Anwendungen T2 - Schwingungen und Wellen in Alltagskontexten N2 - Schwingungen und Wellen zeigen sich in vielen Alltagsphänomenen der Physik, d. h. in der Lebenswelt von Schülerinnen und Schülern. Dazu zählen in der Mechanik Beispiele wie Schaukeln, Seilwellen oder Wasserwellen am Strand, in der Akustik Schallwellen durch beliebige Geräusche oder stehende Wellen in Musikinstrumenten und im Elektromagnetismus die allgegenwärtigen elektromagnetischen Wellen. Letztere haben vielfältigste Anwendungen, z. B. Erhitzen mit Mikrowellengeräten, Kommunizieren mit Smartphones, Datenübertragung mit Lichtleitern oder Fotografieren mit Kameras, ganz zu schweigen von medizinischen Anwendungen der Endoskopie, des Röntgens oder laserbasierten chirurgischen Eingriffen. Viele dieser Anwendungen haben ein enormes Motivationspotenzial in der Lehre, weshalb das Thema fest in Lehrplänen der Sekundarstufen verankert ist. Im Folgenden werden zunächst allgemeine Grundlagen und Gemeinsamkeiten der Beschreibung beliebiger Wellen diskutiert, bevor das Hauptaugenmerk auf elektromagnetische Wellen und ausgewählte Anwendungen gelegt wird. Y1 - 2025 U6 - https://doi.org/10.1007/978-3-662-70949-8_3 SP - 35 EP - 48 PB - Springer ET - 1 ER - TY - JOUR A1 - Vollmer, Michael T1 - How far can we see at day? JF - European Journal of Physics N2 - We discuss the farthest objects on Earth observable for the unaided, healthy naked eye during the daytime, i.e., the maximum visual range for observers on Earth. Visual range depends first on the properties of the material between observer and object and its interaction processes with radiation, but second also on our visual perception system. After a rough comparison of ranges in water, glass, and the atmosphere, we focus on the physical basis of visual range for the latter. As a contrast phenomenon, visual range refers to allowed light paths within the atmosphere. It results from the interplay of geometry, refraction, and light scattering. We present a concise overview of this field by qualitative descriptions and quantitative estimates as well as classroom demonstration experiments. The starting point is the common geometrical visual ranges, followed by extensions due to refraction and limitations due to contrast, which depend on scattering and absorption processes within the atmosphere. The quantitative discussion of scattering is very helpful to easily understand the huge ranges in nature from meters in dense fog to hundreds of kilometers in clear atmospheres. Extreme visual ranges from about 300 km to above 500 km require optimal atmospheric conditions, cleverly chosen locations and times, and a sophisticated topography analysis. Even longer visual ranges are possible when looking through the vertical atmosphere. From the ISS, daytime ranges well above 1000 km are possible. Y1 - 2025 U6 - https://doi.org/10.1088/1361-6404/adc4a0 VL - 46 IS - 3 PB - IOP Science ER - TY - JOUR A1 - Vollmer, Michael T1 - Naked eye celestial objects and phenomena: how far can we see at night? JF - European Journal of Physics N2 - How far can we see with the naked eye at night? Many celestial objects like stars and galaxies as well as transient phenomena such as comets and supernovae can be observed in the night sky. We discuss the furthest distances of such objects and phenomena observable with the naked eye during the night-time for Earth-bound observers. The physics of night-time visual ranges differs from that of daytime observations because human vision shifts from cones to rods. In addition, mostly point sources are observed due to the large distances involved. Whether celestial objects and phenomena can be detected depends on the contrast of their radiation and the background sky luminance. We present a concise overview of how far we can see at night by first discussing the effects of the Earth's atmosphere. This includes attenuation of transmitted radiation as well as its role as a source of background radiation. Disregarding the attenuation of light due to interstellar and intergalactic dust, simple maximum night-time visual range estimates are based on the inverse square law, which can be easily verified by laboratory and demonstration experiments. From the respective calculations, we find that individual stars within the Milky Way galaxy of up to 15 000 light years are observable. Even further away are observable galaxies with several billion stars. The Andromeda galaxy can be observed with the naked eye at a distance of around 2.5 million light years. Similarly, the observability of supernovae also allows a visual range beyond the Milky Way galaxy. Finally, gamma ray bursts as the most energetic events in the universe are discussed concerning naked eye observations. Y1 - 2025 U6 - https://doi.org/10.1088/1361-6404/adbf74 VL - 46 IS - 3 PB - IOP Science ER - TY - JOUR A1 - Stannarius, Ralf A1 - Wang, Jing A1 - Pongó, Tivadar A1 - Fan, Bo A1 - Börzsönyi, Tamás A1 - Hidalgo, Raúl Cruz ED - Alam, M. ED - Das, S.L. ED - Bose, M. ED - Murthy, T.G. ED - Chikkadi, V. ED - Singh, A. ED - Luding, S. T1 - Forces on a sphere suspended in flowing granulate JF - EPJ Web of Conferences N2 - We investigate the forces of flowing granular material on an obstacle. A sphere suspended in a discharging silo experiences both weight of the overlaying layers and drag of the surrounding moving grains. In experiments with frictional hard glass beads, the force on the obstacle was found to be practically flow-rate independent. In contrast, flow of nearly frictionless soft hydrogel spheres added drag forces which increased with the flow rate until reaching saturation at high flow speeds. The total force grew quadratically with the obstacle diameter in the soft, low friction material, while it grew much weaker, nearly linearly with the obstacle diameter, in the bed of hard, frictional glass spheres. In addition to the drag, obstacles embedded in the flowing hydrogel spheres experience a weight force from the top as if immersed in a hydrostatic pressure profile, but negligible counter-forces from below. In contrast, the frictional hard particles create a strong pressure gradient near the upper surface of the obstacle. Numerical simulations provide additional information that is difficult to access experimentally. They reproduce the experimental results and give hints for the origin of the different force contributions. The results have considerable practical importance for the discharge of storage containers with large objects suspended in flowing granular material. Y1 - 2025 U6 - https://doi.org/10.1051/epjconf/202534002019 VL - 340 PB - EDP Sciences ER - TY - JOUR A1 - Harth, Kirsten A1 - Trittel, Torsten A1 - Mohammadi, Mahdieh A1 - Puzyrev, Dmitry A1 - Enezz, Mohammad A1 - Cruz Hidalgo, Raul A1 - Stannarius, Ralf ED - Alam, M. ED - Das, S.L. ED - Bose, M. ED - Murthy, T.G. ED - Chikkadi, V. ED - Singh, A. ED - Luding, S. T1 - Granular gases of rough spheres: Velocity, rotation and collision statistics from in-situ measurements, optical data and simulations JF - EPJ Web of Conferences N2 - Granular gases are not only of interest in fundamental physics, but they can also serve as a test ensembles for the validity of collision models employed in (loose) granular matter. The theoretical literature mainly addresses spheres under ideal conditions and simulations allow full access to all particle parameters, but experiments cannot fulfill these idealizations. We investigate granular gases of soft, rough spheres by combining microgravity experiments and adjusted simulations. We introduce Smart Particles with embedded autarkic micro-sensors for in-situ measurements of rotation rates and accelerations. Additionally, we extract 3D positions, translations and orientations of the particles from stereoscopic video data using Machine-Learning based algorithms. We address the partition of kinetic energy between the degrees of freedom, the angular and translational velocity as well as collision statistics. A simulation is adjusted to experiment parameters, showing good agreement of translational motion, but qualitative differences in the decay of rotational kinetic energy. Y1 - 2025 U6 - https://doi.org/10.1051/epjconf/202534003012 VL - 340 PB - EDP Sciences ER -