Recent Submissions
A simulator for wrong-way driver detection
(2025) Luz, Philipp; Metzner, Martin; Schwieger, Volker
Modern Intelligent Transportation Systems (ITS) often require large amounts of data for their performance analysis. For instance, the Ghosthunter project aimed to utilize smartphone position data to detect and warn wrong-way drivers on German freeways. This was to be accomplished with assured integrity, which required the generation and evaluation of vehicle trajectories. It is challenging to assess this number with real trajectories and a straightforward simulation. Since recording real trajectories, as well as manually creating ground truth data with such a large number of required trajectories, would represent an unaffordable time expenditure, a graphics processing unit (GPU) accelerated simulator based on the Monte Carlo method was developed. In the course of this, based on OpenStreetMap road map data, a model for simulating vehicle behavior, and error models for map and global navigation satellite system (GNSS) errors, vehicle trajectories are generated. Subsequently, these are then used to automatically test and evaluate the algorithms for wrong-way driver detection, which encompasses a map matching algorithm and the algorithm for detecting the direction of travel. The simulator facilitated the generation and evaluation of the required trajectories within a three-day period.
Geometrical and regression-based modeling of shell-like deformations in pneumatically actuated thermoplastic fiber-reinforced hybrid composites
(2025) Born, Larissa; Doshi, Bhavya N.; Ridder, Matthias; Kaiser, Patrick; Gresser, Götz T.
Adaptive structures capable of controlled shape change are increasingly demanded in fields such as aerospace, architecture, and automotive engineering. In these applications, shell-like deformations are essential for achieving smooth surface transitions that satisfy aesthetic requirements or improve aerodynamic performance. While pressure-actuated cellular structures (PACS) and bio-inspired designs have demonstrated promising morphing capabilities, they often involve high geometric complexity, rely on antagonistic actuation systems requiring energy input in both directions of motion, or face limitations in manufacturability. Inspired by biological systems such as insect wings, this study presents a novel approach to implement shell-like deformations in planar, mold-free manufacturable, thermoplastic fiber-reinforced hybrid composites using embedded pneumatic actuators which are integrated into pre-formed cavities within the laminate setup. Previous implementations have been limited to uniaxial bending deformations. In contrast, the integration of multiple actuators enables shell-like deformations through coupled bending axes. Unlike antagonistic systems, the elastic stiffness of the fiber-reinforced composite serves as a passive restoring force, allowing for reversible deformation without additional counteractuation or mechanical complexity. In this study, a simplified geometric model combined with a regression-based approach is developed to predict deformation as a function of actuation pressure p , actuator width w , and the spacing d between coupled actuators and thereby eliminate the need for computationally intensive FEM simulations. The model is validated within the tested range of p (0.0 to 1.8 bar), w (20 to 50 mm) and d (10 to 40 mm): bending angles of up to 92 ∘and corresponding shell radii as small as 50 mm were reproducibly achieved, with a coefficient of determination of R2 = 0.96 for w=20 mm, for example. The proposed design strategy bridges the gap between biologically inspired compliant mechanisms and scalable technical implementation of adaptive shell-like components, offering a low-complexity solution based on a planar, mold-free manufacturing approach.
Rethinking asset administration shell communication types : a systematic mapping study and portfolio-based classification
(2025) Ellwein, Carsten; Dietrich, David; Maisch, Nicolai; Neumann, Rebekka; Ajdinović, Samed; Lechler, Armin; Wortmann, Andreas
Digital twins are a critical backbone technology for modern manufacturing and Industrie 4.0 (I4.0). The Asset Administration Shell (AAS) is becoming a popular foundation for modeling digital twins. Asset Administration Shells come in three successive levels of enhancement, also referred to as AAS (communication) types, though there is no common definition for these types. We conducted a systematic mapping study to find out how they are defined in the literature. As the analysis for type 2 AAS and type 3 AAS remains without direct results, we devised a novel classification schema from our findings via portfolio analysis. This schema can provide a foundation for the precise classification of AAS to guide researchers and practitioners in modeling digital twins.
Spin environment of a superconducting qubit in high magnetic fields
(2025) Günzler, Simon; Beck, Johannes; Rieger, D.; Gosling, Nicolas; Zapata, Nicolas; Field, M.; Geisert, Simon; Bacher, Andreas; Hohmann, J. K.; Spiecker, Martin; Wernsdorfer, Wolfgang; Pop, Ioan-Mihai
Superconducting qubits equipped with quantum non-demolition readout and active feedback can be used as information engines to probe and manipulate microscopic degrees of freedom, whether intentionally designed or naturally occurring in their environment. In the case of spin systems, the required magnetic field bias presents a challenge for superconductors and Josephson junctions. Here we demonstrate a granular aluminum nanojunction fluxonium qubit (gralmonium) with spectrum and coherence resilient to fields beyond one Tesla. Sweeping the field reveals a paramagnetic spin-1/2 ensemble, which is the dominant gralmonium loss mechanism when the electron spin resonance matches the qubit. We also observe a suppression of MHz range fast flux noise in magnetic field, suggesting the freezing of surface spins. Using an active state stabilization sequence, the qubit hyperpolarizes long-lived two-level systems (TLSs) in its environment, previously speculated to be spins. Surprisingly, the coupling to these TLSs is unaffected by magnetic fields, leaving the question of their origin open. The robust operation of gralmoniums in Tesla fields offers new opportunities to explore unresolved questions in spin environment dynamics and facilitates hybrid architectures linking superconducting qubits with spin systems.
Interplay of ferroptotic and apoptotic cell death and its modulation by BH3-mimetics
(2025) Qiu, Yun; Hüther, Juliana A.; Wank, Bianca; Rath, Antonia; Tykwe, René; Aldrovandi, Maceler; Henkelmann, Bernhard; Mergner, Julia; Nakamura, Toshitaka; Laschat, Sabine; Conrad, Marcus; Stöhr, Daniela; Rehm, Markus
Ferroptosis and apoptosis are widely considered to be independent cell death modalities. Ferroptotic cell death is a consequence of insufficient radical detoxification and progressive lipid peroxidation, which is counteracted by glutathione peroxidase-4 (GPX4). Apoptotic cell death can be triggered by a wide variety of stresses, including oxygen radicals, and can be suppressed by anti-apoptotic members of the BCL-2 protein family. Mitochondria are the main interaction site of BCL-2 family members and likewise a major source of oxygen radical stress. We therefore studied if ferroptosis and apoptosis might intersect and possibly interfere with one another. Indeed, cells dying from impaired GPX4 activity displayed hallmarks of both ferroptotic and apoptotic cell death, with the latter including (transient) membrane blebbing, submaximal cytochrome-c release and caspase activation. Targeting BCL-2, MCL-1 or BCL-XL with BH3-mimetics under conditions of moderate ferroptotic stress in many cases synergistically enhanced overall cell death and frequently skewed primarily ferroptotic into apoptotic outcomes. Surprisingly though, in other cases BH3-mimetics, most notably the BCL-XL inhibitor WEHI-539, counter-intuitively suppressed cell death and promoted cell survival following GPX4 inhibition. Further studies revealed that most BH3-mimetics possess previously undescribed antioxidant activities that counteract ferroptotic cell death at commonly employed concentration ranges. Our results therefore show that ferroptosis and apoptosis can intersect. We also show that combining ferroptotic stress with BH3-mimetics, context-dependently can either enhance and convert cell death outcomes between ferroptosis and apoptosis or can also suppress cell death by intrinsic antioxidant activities.
Mixed-mode in-memory computing : towards high-performance logic processing in a memristive crossbar array
(2025) Du, Nan; Polian, Ilia; Bengel, Christopher; Li, Kefeng; Chen, Ziang; Zhao, Xianyue; Hübner, Uwe; Chen, Li-Wei; Liu, Feng; Di Ventra, Massimiliano; Menzel, Stephan; Krüger, Heidemarie
In-memory computing is a promising alternative to traditional computer designs, as it helps overcome performance limits caused by the separation of memory and processing units. However, many current approaches struggle with unreliable device behavior, which affects data accuracy and efficiency. In this work, the authors present a new computing method that combines two types of operations—those based on electrical resistance and those based on voltage-within each memory cell. This design improves reliability and avoids the need for expensive current measurements. A new software tool also helps automate the design process, supporting highly parallel operations in dense two-dimensional memory arrays. The approach balances speed and space, making it practical for advanced computing tasks. Demonstrations include a digital adder and a key part of encryption module, showing both strong performance and accuracy. This work offers a new direction for reliable and efficient in-memory computing systems with real-world applications.
Manipulating wetting and pore filling by wall transparency
(2025) Kondrat, Svyatoslav; Schimmele, Lothar; Giacomello, Alberto; Tasinkevych, Mykola; Dietrich, S.
Atomically thin walls become increasingly prevalent in modern technologies. Exhibiting a unique property-transparency to interparticle interactions-such walls influence processes as diverse as capacitive energy storage, electron transfer, and wetting. However, the impact of wall transparency on wetting and capillary phenomena remains poorly understood. Herein, we employ classical density functional theory to explore how van der Waals interactions across thin solid walls affect capillarity and substrate wetting. Our findings demonstrate that a fluid-filled, sidewise-open channel beneath a thin wall can drastically enhance the lyophobicity of the wall (hydrophobicity if fluid is water), up to the point of effectively transforming lyophilic surfaces into lyophobic ones. Conversely, a fluid covering a thin wall can convert capillary condensation to drying and induce unusual capillary phases within the channel. These findings highlight the potential of wall transparency as a tool for manipulating channel filling and wetting behaviors, emphasizing its significance for interfacial phenomena and fluid adsorption in porous materials.
In vivo tibialis anterior muscle mechanics through force estimation using ankle joint moment and shear wave elastography
(2025) Kaya Keles, Cemre Su; Hiller, Jennifer; Zimmer, Manuela; Ates, Filiz
Understanding how individual muscles contribute to joint mechanics is crucial for biomechanics. This study investigated the tibialis anterior (TA) shear modulus using shear wave elastography (SWE) and studied its relationship with ankle angle, contraction intensity, and joint moment-derived TA force and stress. Fourteen healthy volunteers (seven females, 26.43 ± 3.67 years) participated. SWE from TA, EMG, and ankle joint moment data were collected across ankle angles (- 15° dorsiflexion to 45° plantar flexion) during rest, maximum voluntary contraction (MVC), and isometric submaximal contractions. TA muscle length, passive ankle joint moment, and TA passive shear modulus increased with increasing plantar flexion ( p < 0.001). During MVC, ankle joint moment peaked at 15° (50.13 Nm ± 15.54 Nm) whereas shear modulus remained unchanged (122.96 ± 9.87 kPa) across muscle lengths ( p = 0.068). SWE reflected contractions at 25%, 50%, and 75% MVC ( p < 0.001). TA force estimates peaked between 15° and 30°, with no significant decrease beyond this range. While SWE captured length-dependent passive properties and contraction intensity changes, the shear modulus at MVC (a stiffness measure obtained from SWE) did not align with the tangent modulus (derived from joint-moment-based force-length characteristics). Emphasizing the need for validation, SWE could serve as a valuable tool for understanding muscle mechanics and muscles’ roles in joint dynamics.
Threshold switching in vertically aligned MoS2/SiOx heterostructures based on silver ion migration
(2025) Lee, Jimin; Ahmad, Rana Walied; Cruces, Sofía; Braun, Dennis; Völkel, Lukas; Ran, Ke; Maroufidis Andreadis, Vasileios; Mayer, Joachim; Menzel, Stephan; Daus, Alwin; Lemme, Max C.
Threshold switching (TS) is a non-permanent change in electrical resistance controlled by voltage modulation in two-terminal devices. Silver (Ag) filament-based TS has been observed in two-dimensional transition metal dichalcogenides, which are promising due to their van der Waals gaps, facilitating ion migration and filament formation without disturbing covalent bonds. This work demonstrates the heterostructure growth of vertically aligned molybdenum disulfide (VAMoS2) with an amorphous silicon oxide (SiOx) layer after sulfurization. Ag ion migration through this material stack enables TS. Our Ag/SiOx/VAMoS2/Au devices exhibit low switching voltages of ~0.63 V, high on-state currents over 200 μA, and stable switching exceeding 10⁴ cycles. A physics-based dynamical model identifies two rate-limiting steps for filament formation, and the simulated switching kinetics align with experimental results. Our devices achieve fast switching in 311 ns and spontaneous relaxation in 233 ns. These findings advance understanding of switching mechanisms and highlight their potential for memory and neuromorphic computing applications.
Predicting fracture in disordered network materials using the local intelligent stress threshold indicator
(2025) Bachhav, Bhagyashri; Wu, Zhao; Markert, Bernd; Stamm, Benjamin; Shields, Michael D.; Falk, Michael L.; Bamer, Franz
Network glass fracture occurs as a sequence of elementary events occurring at weak sites in the glass structure. Fracture is a highly complex process that occurs suddenly and without obvious structural or thermodynamic signs prior to the event’s occurrence. We show that a stress threshold value quantified by local mechanical probing highly correlates with nanoscale crack nucleation in a two-dimensional network glass. Subsequently, a neural network-based predictor, the local intelligent stress threshold indicator (LISTI), links the local stress threshold with the undeformed local structural topology. LISTI yields a reliable heatmap indicating soft spots that strongly correlate with the localized initiation and development of the fracture process. Finally, we show that LISTI can be used to find local zones prone to rearrangement in real-measured two-dimensional silica glass structures.