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Senast publicerade
- Automatic Generation of vTESTstudio Test Cases from Natural Language Requirements Using Large Language Models(2026) Zhao, Tianqi; Pan, ShuaixinAutomotive testing still involves substantial manual effort when natural-language requirements are translated into tool-compatible test artefacts. As vehicle functions, carlines and software releases increase, this translation step becomes a growing bottleneck in test development. This thesis investigates a two-phase pipeline for generating vTESTstudio-compatible test artefacts from natural-language automotive requirements using Large Language Models (LLMs). The first phase converts a requirement into a structured intermediate representation of logical test steps. The second phase grounds these steps in valid domain resources, including signals and reusable functions, before constructing the final Vector Test Table (VTT) artefact. This separation makes the generation process easier to inspect, evaluate and control. The thesis further studies retrieval-based grounding, parameter-efficient fine-tuning for intermediate representation generation, and retrieved skill guidance for improving logical planning. On the small evaluation sets used in this thesis, the proposed pipeline produced useful test artefacts in selected cases, but human review remained necessary. This is assessed up to the generated logical test steps and the coverage of the VTT artefacts against reference cases, not their syntactic validity or execution in vTESTstudio or CANoe. Within these limits, retrieval tended to improve grounding indomainness and signal coverage, while fine-tuning improved the validity, consistency and domain style of intermediate representations. Retrieved skills helped planningoriented aspects such as logical adequacy and structural quality, though larger skill contexts could make downstream grounding harder. Overall, the thesis suggests that requirement-driven automotive test generation is more controllable when requirement interpretation, domain grounding and artefact construction are treated as separate stages.
- Software-Defined Radio Testbed for 6G Research(2026) Ahmad, Sajeel; Collard, Niclas Christopher; Martinsson, Martin; Mörck, Gabriel; Rahimi, SammyThe increasing demand for wireless communication and the limitations of current cellular networks motivate research into new cellular network architectures. Traditionally, the philosophy in cellular networks has been to have one base station per geographical area, and that a cellular user is only connected to one base station at a time. This has limitations with regard to uneven coverage and poor cellular quality far from base stations. Distributed multiple-input multiple-output (D-MIMO) systems aim to resolve those limitations, providing users with improved cellular network performance. Chalmers University of Technology has a D-MIMO testbed that is used in research. Although the testbed fulfills its intended purpose, its current setup is based on costly laboratory equipment, which limits experimental flexibility and restricts scalability. Therefore, this thesis aims to implement a more flexible and cost-effective method to emulate user equipment in the current testbed. The project first focused on designing and validating a point-to-point communication link between two software-defined radios, evaluating several key aspects of the radios, including bandwidth limitations, maximum achievable throughput, and limitations related to signal duration and onboard memory. The results show that the system can operate with a maximum bandwidth of 49.51 MHz and a maximum throughput of 54.25 Mbit/s. The developed communication system enables reliable data transmission and reception, using preambles to detect and correct transmission errors and verify the accuracy of the transmitted data. It operates without external reference signals and compensates for carrier frequency offsets. Bit error rate (BER) and error vector magnitude (EVM) were used to evaluate the system. In indoor conditions, a BER of 0 and an EVM of 6.25% were achieved, allowing it to transmit data reliably between two radios. The system was also successfully integrated into the D-MIMO testbed, where it was subjected to strict synchronization constraints. The transmitted signal was successfully received by all six remote radio heads and combined using maximum ratio combining, achieving a BER of 0 and an EVM of 4.64%.
- Turbulence and Near-Wall Modeling for Commercial Vehicle Aerodynamics: A Comparative Study of Scale Resolving Approaches(2026) Karlsson, Alexander; Serbülent, BerkenThis thesis presents a comparative study of turbulence and near-wall modeling for aerodynamic simulations of commercial vehicles. The work addresses a central challenge in industrial computational fluid dynamics, namely how to obtain reliable flow predictions without the prohibitive cost of high-fidelity scale-resolving methods. Two geometries were investigated: a simplified truck model and a detailed production-scale Volvo truck. The simplified case was used to evaluate wall-modeled LES, hybrid RANS–LES methods, Scale-Resolving Hybrid methods, and selected RANS formulations against a wall-resolved LES reference and experimental data. The production truck case was used to assess model behavior under full-scale wind-tunnel conditions. Additional simulations investigated model sensitivity to numerical choices such as time step, inner iterations, and prism-layer design. Across both configurations, the turbulence model had a strong influence on predicted separation behavior, wake structure, and drag. For the simplified truck, DDES Elliptic Blending k-ε and wall-modeled LES showed the best overall agreement with the wall-resolved LES. For the full-scale truck, DDES Elliptic Blending k-ε gave the most accurate absolute drag predictions and the best agreement for yaw-weighted drag. However, DDES k-ω SST captured the relative drag differences between geometry variations more accurately. The sensitivity studies showed that the current numerical setup is generally robust. Timestep reduction and prism–layer variation showed only limited effects in aerodynamic drag. Furthermore, it was shown that 6 to 8 inner iterations generally resulted in convergence within each timestep. Overall, the results show that no single turbulence model is optimal for all purposes, and that model selection in industrial vehicle aerodynamics should be guided by the specific engineering objective.
- A Bayesian Framework for Dark Photon Searches at LDMX(2026) Berger, AdamDespite decades of experimental searches, dark matter, a hypothetical form of matter with highly suppressed electromagnetic interactions, has yet to be detected. The absence of any detection in the 10 GeV–TeV mass range has motivated searches in lower mass ranges, reaching sub-GeV levels. Due to the Lee-Weinberg bound, a thermal-relic dark matter particle at this mass scale requires a new force mediator to bring the annihilation cross-section into agreement with the observed relic density. This force mediator is dubbed the dark photon, and several experiments designed to produce and detect it have been built or are currently under construction. The main objective of this thesis is to develop a Bayesian framework for inferring the coupling strength and mass of the dark photon using data from the upcoming Light Dark Matter eXperiment (LDMX), a fixed target experiment where dark photons are expected to be produced in electron-tungsten collisions. The framework is validated on MadGraph5- simulated data sets to quantify LDMX’s (Phase II) detection capabilities and parameterinference power. This task is accomplished using dynamic nested sampling, designed for estimating posteriors and calculating marginal likelihoods. The secondary objective is to investigate whether the degeneracy between the dark photon mass and interaction model can be resolved through a combined analysis of the recoil-electron’s transverse momentum |pT | and total energy E. The degeneracy is explored by comparing Bayes factors computed from the marginal likelihoods of the different models. The framework recovers the dark photon mass and coupling accurately for benchmarks corresponding to thermal relic targets for complex scalar dark matter with R ≡ mA′/mχ = 2.5, while identifying benchmarks with R = 2.2, producing fewer expected signal events, as being below detection threshold. Using two-dimensional (E, |pT |) kinematics, the Bayes factor comparison breaks the mass-model degeneracy between the interaction model groups ([KM, C, A] and [M, E]), with maximum Bayes factors of lnK = 591. One-dimensional analysis of E and |pT | alone still separates the model groups, though less decisively, with maximum Bayes factors of lnK ≈ 42 for E alone and lnK ≈ 22 for |pT | alone. The introduction of a relic-target prior on gf further separates KM from [C, A], at the cost of additional assumptions.
- A Risk-Based Evaluation of the Handover Process for Information Transfer at the Swedish Transport Administration(2026) MartanderThis thesis investigates the handover process between the Investments and Main tenance business areas at the Swedish Transport Administration (STA), with a focus on identifying deficiencies in information transfer and organisational prac tices. The study aims to analyse how the process is carried out in practice, where the risks and challenges arise, and which improvement measures can most effec tively reduce these risks. The research is based primarily on qualitative interviews with personnel involved in the handover process, complemented by a qualitative risk assessment. To evaluate and prioritise potential improvement measures, the Analytic Hierarchy Process (AHP) was applied, using time, cost, and health and safety as decision criteria. The findings indicate that the handover process is generally functional but exhibits significant variation in implementation. While successful outcomes are common, recurring challenges are identified in areas such as stakeholder involvement, unclear responsibilities, fragmented information man agement, and gaps in competence. These issues give rise to risks related to delays, increased costs, and, in some cases, safety-critical errors. In addition, the AHP analysis shows that early involvement of specialists from Maintenance is the most effective measure for reducing risk, as it addresses root causes and prevents errors in early project stages. Measures such as temporary project groups and full-time handover coordinators contribute to improved coordination and continuity, while mandatory training provides long-term support for competence development but has a more limited immediate impact. Besides, the study concludes that im proving the handover process requires a focus on early, preventive interventions combined with strengthened organisational coordination and knowledge sharing. The findings provide practical guidance for the STA and contribute to a broader understanding of how handover processes in infrastructure projects can be im proved to enhance efficiency, reliability and safety.