Repository for Publications and Research Data
News from the ETH Library
Recently Added
Acoustic Reliefs
Item type: Journal Article
Chew, Jeremy; Piovarči, Michal; Xue, Kangrui; et al. (2025)
We present a framework to optimize and generate Acoustic Reliefs: acoustic diffusers that not only perform well acoustically in scattering sound uniformly in all directions, but are also visually interesting and can approximate user-provided images. To this end, we develop a differentiable acoustics simulator based on the boundary element method, and integrate it with a differentiable renderer coupled with a vision model to jointly optimize for acoustics, appearance, and fabrication constraints at the same time. We generate various examples and fabricate two room-scale reliefs. The result is a validated simulation and optimization scheme for generating acoustic reliefs whose appearances can be guided by a provided image.
Cross-Modal Diffusion for Biomechanical Dynamical Systems Through Local Manifold Alignment
Item type: Working Paper
Dey, Sharmita; Ravindran Nair, Sarath (2025)
We present a mutually aligned diffusion framework for cross-modal biomechanical motion generation, guided by a dynamical systems perspective. By treating each modality, e.g., observed joint angles () and ground reaction forces (), as complementary observations of a shared underlying locomotor dynamical system, our method aligns latent representations at each diffusion step, so that one modality can help denoise and disambiguate the other. Our alignment approach is motivated by the fact that local time windows of and represent the same phase of an underlying dynamical system, thereby benefiting from a shared latent manifold. We introduce a simple local latent manifold alignment (LLMA) strategy that incorporates first-order and second-order alignment within the latent space for robust cross-modal biomechanical generation without bells and whistles. Through experiments on multimodal human biomechanics data, we show that aligning local latent dynamics across modalities improves generation fidelity and yields better representations.
UMUD: A Web Application for Easy Access to Musculoskeletal Ultrasonography Datasets
Item type: Dataset
Ritsche, Paul; Sarto, Fabio; Santini, Francesco; et al. (2025)
TinyDEM: Minimal open granular DEM code with sliding, rolling and twisting friction
Item type: Journal Article
Vetter, Roman (2026)
This article introduces TinyDEM, a lightweight implementation of a full-fledged discrete element method (DEM) solver in 3D. Newton's damped equations of motion are solved explicitly for translations and rotations of a polydisperse ensemble of dry, soft, granular spherical particles, using quaternions to represent their orientation in space without gimbal lock. Particle collisions are modeled as inelastic and frictional, including full exchange of torque. With a general particle-mesh collision routine, complex rigid geometries can be simulated. TinyDEM is designed to be a compact standalone program written in simple C++11, devoid of explicit pointer arithmetics and advanced concepts such as manual memory management or polymorphism. It is parallelized with OpenMP and published freely under the 3-clause BSD license. TinyDEM can serve as an entry point into classical DEM simulations or as a foundation for more complex models of particle dynamics. PROGRAM SUMMARY Program Title: TinyDEM CPC Library link to program files: (to be added by Technical Editor) Developer's repository link: — Licensing provisions: BSD 3-clause Programming language: C++11 Supplementary material: Videos 1–6 Nature of problem: Dynamics and statics of polydisperse ensembles of visco-elastic, frictional, non-adhesive spherical particles (such as in granular media) in 1D, 2D and 3D. All three modes of torque exchange (sliding, rolling and twisting) are modeled with slip-stick Coulomb friction. Solution method: The discrete element method is used to solve Newton's damped equations of motion for particle translations and rotations with the semi-implicit Euler scheme. Quaternions are used to represent particle orientations. For efficient collision detection, a linked cell list is used. A static geometrical environment can be defined with a discrete mesh. The program is parallelized with OpenMP for shared-memory systems. Additional comments including restrictions and unusual features: The source code is exceptionally compact, consisting of only about 600 commented lines in two files—a header and a source file. With no dependencies, it is highly portable and accessible, making it also suited for educational purposes.
Wireless Low-Latency Synchronization for Body-Worn Multi-Node Systems in Sports
Item type: Conference Paper
Nico Krull; Lukas Schulthess; Michele Magno; et al. (2025)
Biomechanical data acquisition in sports demands sub-millisecond synchronization across distributed body-worn sensor nodes. This study evaluates and characterizes the Enhanced ShockBurst (ESB) protocol from Nordic Semiconductor under controlled laboratory conditions for wireless, low-latency command broadcasting, enabling fast event updates in multi-node systems. Through systematic profiling of protocol parameters, including cyclic-redundancy-check modes, bitrate, transmission modes, and payload handling, we achieve a mean Device-to-Device (D2D) latency of 504.99 +- 96.89 us and a network-to-network core latency of 311.78 +- 96.90 us using a one-byte payload with retransmission optimization. This performance significantly outperforms Bluetooth Low Energy (BLE), which is constrained by a 7.5 ms connection interval, by providing deterministic, sub-millisecond synchronization suitable for high-frequency (500 Hz to 1000 Hz) biosignals. These results position ESB as a viable solution for time-critical, multi-node wearable systems in sports, enabling precise event alignment and reliable high-speed data fusion for advanced athlete monitoring and feedback applications.