General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DRT-24-0454
Direction
DRT
Thesis topic details
Category
Technological challenges
Thesis topics
Differentiable surrogate for simulation-based inference
Contract
Thèse
Job description
Many models of complex phenomena (physics, molecular dynamics, etc.) have no
global analytical expressions but admit implementations in silico in form of
forward simulators. In turn, forward simulations are used to solve inverse
problems: given observations of the phenomena find its initial conditions
viewed as input parameters of the simulator.
In statistical terms solving such an inverse problem corresponds to sampling
from a (bayesian) posterior distribution with the implicit likelihood given by the
simulator - this provides (at least) an answer to the problem with
error bounds in form of uncertainty estimates. High dimensionality and/or
computational load hinder use of simple classical methods (like ABC or
Kernel Density Estimator) and lead to construction of surrogates that approximate
the intractable likelihood coupled with amenable schemes for posterior sampling.
Recent advances in Automatic Differentiation models allow construction of
such surrogates which are yet in their early development. In this thesis
we aim to study and develop new ways to construct differentiable surrogates
and apply them on a number of realistic problems starting
with a number of applications in nuclear imaging.
University / doctoral school
Ecole Doctorale de Mathématiques Hadamard (EDMH)
Ecole Polytechnique
Thesis topic location
Site
Saclay
Requester
Position start date
01/02/2024
Person to be contacted by the applicant
BARAT Eric eric.barat@cea.fr
CEA
DRT/DIN/LIACI
CEA-Saclay
0169088814
Tutor / Responsible thesis director
DURMUS Alain alain.durmus@polytechnique.edu
Ecole Polytechnique
CMAP
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