This thesis develops high-performance numerical methods for convex optimization, variational inequalities, and game theory, targeting computational bottlenecks in modern large-scale systems. By leveraging the underlying mathematical structure of these problems, this work bridges the gap between abstract operator theory and real-time control and strategic decision-making applications.
The first core contribution focuses on accelerating first-order methods for smooth and nonsmooth convex optimization. We introduce adaptive step-size rules and coupled smoothing–momentum techniques that achieve optimal convergence rates. These methods are designed to exploit problem structure, ensuring computational efficiency and enabling fast convergence without requiring prior knowledge of global problem parameters.
Extending beyond single-agent optimization, the research adopts the framework of variational inequalities to address complex equilibrium problems. We propose projection-free algorithms and specialized splitting methods for settings in which traditional projection operators are computationally expensive. This unified approach enables efficient computation of equilibria in dynamic games and distributionally robust models, where decision-makers must account for both strategic interactions and data uncertainty.
The practical relevance of these developments is demonstrated through real-world applications and the introduction of an open-source computational toolkit. Collectively, these contributions provide a scalable and robust framework for fast, structure-aware decision-making in complex multi-agent systems.

This thesis presents the design of integrated interface circuits for inductive resonant wireless power transfer (WPT) systems, targeting implantable medical devices (IMDs). IMDs require compact, high-efficiency, and robust wireless power solutions capable of adapting to link and load variations. This thesis systematically develops three receiver and system architectures: voltage-mode (VM), hybrid voltage-/current-mode (V/CM), and resonant-current-mode (RCM), to improve power conversion efficiency (PCE), voltage conversion ratio (VCR), and adaptability over state-of-the-art designs.

Radiation therapy uses ionizing radiation to kill tumor cells by damaging DNA and other biomolecules either directly or via reactive oxygen species generated during water radiolysis. However, radiation effectiveness is often limited by normal tissue tolerance and tumor radioresistance, which motivates the use of radiosensitizers to enhance tumor response. Photosensitizers are being explored as radiosensitizers because they can promote the formation of additional reactive oxygen species and other reactive species under ionizing radiation. However, the mechanisms by which photosensitizers respond to ionizing radiation remain unclear, and reported radiosensitizing outcomes are not always consistent. This thesis therefore investigates the mechanism of how photosensitizers generate reactive oxygen species under different radiation conditions and assesses their potential as radiosensitizers across radiation therapy modalities with different dose rates....

This thesis researches if the traditional Japanese woodworking technique, Kigumi, can offer a solution for a circular and biobased building industry. The construction sector is currently responsible for about 37% of global CO2 emissions. Although wood is a sustainable alternative to concrete and steel, circularity in modern construction is often limited by the use of glue and steel screws. These methods make it difficult to take buildings apart without damaging the wood, which makes reuse difficult.
Kigumi offers a unique solution by using complex, pure wooden joints without glue or metal. In this research, five case studies are analyzed from the ancient Hōryū-ji temple to modern projects like the Tamedia office building and the Expo 2025 ring. The research looks at the technical quality, the level of demountability, and the seismic resistance of these joints. An important part of the thesis is the
transition from handwork to modern technology.
While Kigumi could previously only be made by specialized carpenters (Miya-daiku), 5-axis CNC milling now ensures that these joints can be produced quickly, precisely, and on a large scale. The conclusion of this research is that the combination of old Japanese wisdom and modern robotics is a realistic path toward a sustainable future. It makes buildings fully demountable, allowing wood to be reused at a high level and drastically reducing the impact on the environment.

Deltas are dynamic landforms that develop through the interaction of sediment supply, hydrodynamics, and accommodation. They support large human populations and important ecosystems, yet many deltas are increasingly threatened by subsidence and sea-level rise. One of the key processes contributing to subsidence is sediment compaction. Compaction is an inherent process in delta systems. However, the impact of syn-depositional compaction during active delta formation over millennial timescales remains poorly constrained. This dissertation investigates how syn-depositional compaction influences delta morphodynamics, sediment distribution, and levee breaching, using a process-based numerical modelling approach. These questions are addressed in Chapters 2, 3, and 4 of this dissertation.

To address the above-mentioned questions, we apply and progressively refine compaction formulations within the Delft3D 4 - FLOW code. This approach focuses on mechanical compaction because it contributes to the largest sediment volume reduction compared to biological and chemical compaction. Additionally, it mainly operates within the active part of the delta top. This type of compaction occurs in two phases, primary and secondary compaction, driven by overburden weight and simulated time. Both phases lead to pore fluid expulsion, resulting in sediment volume reduction and lowering of the bed surface (subsidence). By switching compaction on and off in model simulations, the effects of syn-depositional compaction on delta development are assessed. Quantitative metrics are developed to enable comparison between simulations, including changes in delta geometry, sediment mass distribution, accommodation generation, and sediment erodibility.

Modelling results show that syn-depositional compaction generates additional accommodation during delta development, which alters delta morphology. Morphological changes are more prominent in mud-rich deltas than in sand-rich deltas, which experience larger compaction-induced volume reduction for the same compaction rate scenario. In higher compaction rate scenarios, accommodation increases at the delta top, leading to more sedimentation and more evenly distributed sediment at the delta top. This results in a less significant area increase and a wider delta top with a smoother coastline. These morphological responses emerge from feedback between compaction-induced additional accommodation, sedimentation, and channel dynamics.

Additional accommodation generated by syn-depositional compaction also affects the distribution of sediment mass across delta depositional areas. Modelling results show that increased accommodation on the delta plain promotes sedimentation in this area, thereby reducing sediment delivery to the mouth bar and beyond. Further increases in accommodation lead to enhanced lateral sediment redistribution associated with channel relocation, with sedimentation mainly occurring in the mouth bar. Changes in sedimentation within a depositional area are accompanied by compensating changes elsewhere, indicating interdependencies within the delta-wide sediment budget influenced by syn-depositional compaction. These results demonstrate that compaction-induced accommodation redistributes sediment beyond the immediate subsidence area, affecting sedimentation across the entire delta system.

In addition to generating additional accommodation, syn-depositional compaction increases sediment resistance to resuspension. Levees act as key sediment conduits in delta systems, and the location and timing of levee breaching are commonly assessed using proxies that describe the influence of topography on hydraulic forcing acting on levee deposits. However, the role of sediment properties, particularly levee resistance to resuspension, remains poorly constrained. The modelling results show that commonly used proxies, such as superelevation and gradient advantage, are relevant in predicting when and where levee breaching is initiated, but they are insufficient to describe breach progression, which depends on the balance between flow-induced shear stress and sediment resistance to resuspension. Syn-depositional compaction modifies both bed elevation and sediment erodibility, thereby influencing whether breaches are sustained or abandoned.

Overall, this dissertation demonstrates that syn-depositional compaction is a fundamental process influencing simulated delta evolution over millennial timescales. While numerical models cannot capture all processes operating in natural deltas, they provide a controlled framework to explore process interactions that are difficult to observe directly in the field. The results show that syn-depositional compaction affects delta morphology, sediment distribution, and levee breaching, and therefore represents a critical mechanism that should be included in process-based delta modelling studies.