BEGIN:VCALENDAR VERSION:2.0 PRODID:Linklings LLC BEGIN:VTIMEZONE TZID:Asia/Tokyo X-LIC-LOCATION:Asia/Tokyo BEGIN:STANDARD TZOFFSETFROM:+0900 TZOFFSETTO:+0900 TZNAME:JST DTSTART:18871231T000000 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20250110T023309Z LOCATION:Hall B5 (1)\, B Block\, Level 5 DTSTART;TZID=Asia/Tokyo:20241203T150800 DTEND;TZID=Asia/Tokyo:20241203T151900 UID:siggraphasia_SIGGRAPH Asia 2024_sess106_papers_1139@linklings.com SUMMARY:Solving Inverse PDE Problems using Grid-Free Monte Carlo Estimator s DESCRIPTION:Technical Papers\n\nEkrem Fatih Yilmazer (EPFL), Delio Vicini (Google Inc.), and Wenzel Jakob (EPFL)\n\nPartial differential equations c an model diverse physical phenomena including heat diffusion, incompressib le flows, and electrostatic potentials. Given a description of an object's boundary and interior, traditional methods solve such PDEs by densely mes hing the interior and then solving a large and sparse linear system derive d from this mesh. Recent grid-free solvers take an alternative approach an d avoid this complexity in exchange for randomness: they compute stochasti c solution estimates and generally bear a striking resemblance to physical ly-based rendering algorithms.\n\nIn this article, we develop algorithms t argeting the inverse form of this problem: given an already existing solut ion of a PDE, we infer parameters characterizing the boundary and interior . In the grid-free setting, there are again significant connections to ren dering, and we show how insights from both fields can be combined to compu te unbiased derivative estimates that enable gradient-based optimization. In this process, we encounter new challenges that must be addressed to obt ain practical solutions. We introduce acceleration and variance reduction strategies and show how to differentiate branching random walks in reverse mode.\n\nWe finally demonstrate our approach on both simulated data and a real-world electrical impedance tomography experiment, where we reconstru ct the position of a conducting object from voltage measurements taken in a saline-filled tank.\n\nRegistration Category: Full Access, Full Access S upporter\n\nLanguage Format: English Language\n\nSession Chair: Yonghao Yu e (Aoyama Gakuin University) URL:https://asia.siggraph.org/2024/program/?id=papers_1139&sess=sess106 END:VEVENT END:VCALENDAR