Chalmers Open Digital Repository

Welcome to Chalmers Open Digital Repository!

Here you can find:

Student theses and papers
Digital special collections, such as Chalmers modellkammare
Selected project reports

Research publications, reports and dissertations can be found in research.chalmers.se

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Now showing 1 - 2 of 2

Recent Submissions

Semantic Communication for Closed-loop Sensing-Communication-Control Systems
(2026) Wang, Jingcheng
This thesis investigates channel state information (CSI) as a sensing input for position estimation and simulated closed-loop control, motivated by the Level-2 interpretation of semantic communication. It evaluates task-relevant state extraction rather than a modeled semantic transmission link. A simulation pipeline combines Sionna RT channel generation in a street-canyon scene, a ResNet-based estimator, Kalman filtering, and linear quadratic regulator (LQR) control. Complex CSI is represented by real and imaginary components across antennas and subcarriers. The neural model predicts two-dimensional position and coordinate-wise variance. Position predictions supply measurements to the filter, while the controller acts on the filtered state. The learned covariance is evaluated separately; the main closed-loop experiments use fixed diagonal covariance. On a random held-out test split of 2000 samples within the simulated scene, the estimator achieves a mean Euclidean localization error of 0.857 m, an RMSE of 1.204 m, and a median error of 0.673 m. Joint antenna–subcarrier masking yields an accuracy plateau: retaining 56.25% of the full CSI coefficients gives the lowest observed mean error, 0.626 m. This does not establish bitrate or energy savings. Predicted covariance is weakly correlated with localization errors and fails the reported consistency check, limiting its direct use in Kalman filtering. The fixed-covariance sweep demonstrates tracking sensitivity to measurement confidence. In one paired seed-0 rollout per setting, a variance of 1 m2 per coordinate yields the lowest true-state LQR cost, 750.27, and tracking RMSE, 0.683 m, among the tested settings. These findings characterize within-scene localization, uncertainty limitations, and covariance-sensitive tracking. Ideal interfaces, one scene and trajectory, and missing controller controls restrict conclusions about communication benefits, generalization, and the contribution of individual pipeline components. Calibrated uncertainty and broader evaluation are needed before deployment.
Multi-View Pedestrian Detection Without Scene-Specific Fine-Tuning via 3D Foundation Models
(2026) Lai, Bowen; Zhang, Junchao
Multi-view pedestrian detection in occluded scenes often relies on scene-specific 3D reconstructions, which are accurate but require lengthy optimization. This thesis investigates whether an off-the-shelf 3D vision foundation model (MapAnything) can provide metric 3D point clouds for this task without scene-specific fine-tuning. We first characterize the foundation model’s geometric error, finding that calibrated inputs yield manageable scale drift correctable via ground-plane scaling, whereas uncalibrated inputs cause severe frame-to-frame distortion (averaging 66.0 cm spatial drift), degrading detection accuracy from 59.9 MODA to 29.1 MODA. To integrate this foundation-model geometry into a detector, we build a differentiable bird’s-eye view (BEV) pipeline based on Lift-Splat-Shoot and PointPillars. To handle the 30–80 cm point cloud dispersion typical of foundation models, we use dilated convolutions to enlarge the BEV backbone’s receptive field. This architecture achieves 68.7 MODA on Wildtrack and 64.0 MODA on MultiviewX. Compared to a per-scene optimized baseline (DCHM), which reaches 83.0 MODA in our singleiteration supervised reproduction and approximately 95 MODA in the best supervised results reported by its authors, the gap reflects the limitations of off-the-shelf foundation geometry. Finally, we show that auxiliary mechanisms like soft-depth sampling can cause oversmoothing, and cross-subset experiments reveal that BEV convolutional networks severely overfit to the training camera rig layout (dropping up to 28.35 MODA when testing on unseen camera subsets).
Interactive Simulation Systems for Industrial Equipment - Supporting System Verification Through Interactive Information Visualization
(2026) Persson, Jakob; Tan Quach, Kevin
Industrial process systems rely on precise level measurements to run safely and profitably. To verify that these measuring instruments work correctly under realistic conditions, engineers use simulation setups like the Interactive Plant Environment (IPE). However, exploring the massive amounts of live data generated during these tests is difficult without specialized tools. The primary purpose of this project is to answer how interactive simulation systems should be designed to support system verification. To investigate this, a prototype interface was developed to allow test engineers to easily run automated scripts, control the system manually, and analyze real-time data. Using a Research through Design (RtD) approach and the Double Diamond process, the project started with semi-structured interviews to understand the daily work flows and frustrations of expert test engineers. Insights from this pre-study indicated that standard usability checklists are insufficient for live industrial environments. By combining these empirical findings with foundational Human-Computer Interaction (HCI) principles and Information Visualization (InfoVis) theory, the project introduces a set of custom design guidelines: spatial fidelity and dynamic state mapping, flexible test control, stable views for live data, clear error handling, proactive input validation and defensive safety nets, and data filtering. Based on these guidelines, a functional web application prototype was built featuring visual tank models, live data plotting, and seamless switching between automated and manual execution. A heuristic evaluation of the prototype suggested that the interface supports expert test engineers by reducing cognitive load through visual metaphors and maintaining stable views during live data inspection. While the prototype managed complex testing scenarios, it also exposed vulnerabilities regarding conflicting commands and unguided error recovery, which directly resulted in refining and expanding the guidelines. Ultimately, this project proposes a set of domain-specific guidelines that can assist designers and developers in building interactive simulation and verification systems for similar industrial contexts.
Bridging Infrastructure; A Broad Study, Applied On Älvängen
(2025) Berntsson, Helge
As society has developed and expanded, the transport network has grown. The small, simple path has turned into a street, and today that street is a motorway that runs straight through the community. This is a common sight in towns that have grown with the car, and it’s a structure that creates infrastructure barriers. An obstacle along someone’s path, creating barrier effects. This structure exists today in Älvängen. The motorway and railway separate large areas next to the town centre, but the barrier effects can be considered minor as there is currently no attraction to the separated areas. This may change if the municipality’s visions for the future are realised. How can barrier effects then be prevented when the need to cross the motorway and railway is created? The foundation of the thesis is based on two theoretial oriented parts, one of which has been to test whether the conceptual model of barrier effects developed by Job van Eldijk as part of his research on infrastructure barriers can be used to develop a needs specification for a specific location, in this case Älvängen. The second part is a study of reference projects, using research for design as a methodology. How have infrastructure barriers been dealt with in different places around the world, and what can we learn from this? The lessons learned from the reference projects have then been used to create a number of design principles that should be taken into account and used when designing new pedestrian and cycle bridges with the aim of reducing barriers. These design principles have then been applied, together with the needs identified for Älvängen, to create a proposal for a new pedestrian and cycle bridge over the motorway and railway in Älvängen. A new pedestrian and cycle bridge that will help the residents of Älvängen to travel between the town centre and the green areas along the Göta Älv river, while minimising any future barrier effects that may arise. Finally, the lessons learned from the project as a whole are summarised, with a strong focus on footbridges, which have become the core of the project.
Combining Fluorescence and Nanofluidic Scattering Microscopy For Biomolecule Characterization
(2026) Sofra, Christina
Characterization of single biomolecules is fundamental for understanding biological processes at the molecular level. Although fluorescence microscopy using nanofluidic devices has been a longstanding workhorse for the study of single biomolecules, crucial limitations exist, with the main being alterations in structural conformation due to fluorophore binding. Techniques based on detection of scattering light, such as iSCAT (Interferometric scattering microscopy) microscopy, have emerged and evolved to label-free biolomecular probing techniques. Nanofluidic scattering microscopy (NSM), a technique relying on freely diffusing biomolecules inside nanofluidic structures, has also been developed the last years with impressive results as a reliable label-free characterization method. This thesis investigates the applicability of NSM as a label-free technique for the characterization of single DNA molecules confined inside nanochannels, using fluorescence microscopy as a reference method. Both measurements were performed under comparable experimental conditions to evaluate the capability of both techniques in determining DNA extension. In parallel, a dedicated analysis algorithm was developed for the fluorescence measurement technique, including automated molecular detection, trajectory extraction, and DNA length estimation using errorfunction fitting. Measurements were performed on DNA samples prepared in 0.5×TBE and 0.05×TBE. Fluorescence microscopy showed larger and more variable molecular extensions in 0.05×TBE, while NSM yielded similar median extensions under both conditions, with a broader distribution in 0.05×TBE. Correlated measurements showed a positive relationship between the two methods, although individual discrepancies and potential selection bias require further investigation before quantitative agreement can be established. The fluorescence analysis also requires further optimization for reliable measurements of DNA extension fluctuations. This work establishes an experimental and analytical framework for simultaneous fluorescence microscopy and NSM measurements of confined single DNA molecules.