In our complex world, how do humans learn and make decisions when their cognitive resources are limited? My thesis introduces a new theory called "policy compression" to answer this question! The basic idea is that people simplify their decision-making processes to reduce the mental effort required, without significantly compromising the benefits or rewards of those decisions. I use computational modeling, human experiments, and brain studies in rats to explain why people exhibit certain decision-making patterns, like the tendency to stick with familiar choices, and why they use strategies like "chunking" to reduce mental load. I also propose that different brain regions work together to balance mentally taxing decisions with more automatic, habitual decisions. This allows the brain to optimize behavior in complex environments. In conclusion, my thesis offers a new way to understand how humans and animals make decisions with limited mental resources, and shows how the brain organizes itself to handle decision-making efficiently.

Hypersonic missiles generate plasma that can interfere with radar detection. This research uses open-source, physics-based simulations to model plasma formation efficiently. Results show plasma usually has little effect on radar, but when it does, the method provides industry with a fast, cost-effective way to design improved radar systems for missile detection.

Aneurysms cause hundreds of thousands of deaths each year, yet most never rupture. This research applies vascular mechanics, medical imaging, and multiscale simulations to model how arteries grow and weaken over time. By predicting which aneurysms will burst, it aims to guide safer, patient-specific treatment decisions and prevent fatal outcomes.

This research shows that real fires move through buildings, creating uneven heating that can cause structural collapse. Using full-scale fire tests and simulations, it demonstrates that traditional static fire-resistance testing is inadequate. Designing buildings for traveling-fire scenarios is essential to prevent collapse and protect lives.