Reachability on Omanshu Thapliyal

Provable Safety and Efficient Memory for Language Models

Mon, 01 Jan 0001 00:00:00 +0000

Problem

Putting language models into safety-critical operations raises questions that accuracy benchmarks do not answer. If a safety filter says a prompt is safe, will it still say so when the prompt is changed slightly? When a model is adapted to a new task, what has the added component learned to remember, and can that be bounded?

Both are questions about dynamics. State space models (SSMs), the recurrent architecture behind Mamba and S4, are dynamical systems, so the tools used to certify controllers apply to them directly: reachability, contraction and model reduction. This project uses those tools to build language-model components whose behavior can be checked, not just measured.

Safety and Cybersecurity of Cyberphysical Systems

Mon, 01 Jan 0001 00:00:00 +0000

Problem

Drones, air taxis and robot teams are cyberphysical systems: physical machines run by software and linked by networks. Before they can be trusted in safety-critical airspace, we need to know every state they could reach, and whether any of those states is unsafe. The exact answer comes from solving high-dimensional partial differential equations, which is out of reach once a system is nonlinear, learned from data by a neural network, spread across many agents, or under cyberattack.

Unmanned Aerial Vehicle Safe Autonomous Operations

Mon, 01 Jan 0001 00:00:00 +0000

Problem

Air taxis and delivery drones are expected to fly autonomously over cities, but public trust is low: in one survey cited in this work, only 26% of respondents trusted autonomous air taxis. Before these vehicles can fly on their own, their controllers need a clear safety guarantee: the set of states from which the vehicle can still avoid a collision or reach its landing pad. Computing that set means solving a Hamilton-Jacobi equation, and grid-based solvers become impractical for realistic vehicle models with 6 to 12 states. Learning-based controllers scale better, but they are hard to certify.