0000000000378913

AUTHOR

Petteri Piiroinen

0000-0002-1356-7052

showing 3 related works from this author

From Feynman–Kac formulae to numerical stochastic homogenization in electrical impedance tomography

2016

In this paper, we use the theory of symmetric Dirichlet forms to derive Feynman–Kac formulae for the forward problem of electrical impedance tomography with possibly anisotropic, merely measurable conductivities corresponding to different electrode models on bounded Lipschitz domains. Subsequently, we employ these Feynman–Kac formulae to rigorously justify stochastic homogenization in the case of a stochastic boundary value problem arising from an inverse anomaly detection problem. Motivated by this theoretical result, we prove an estimate for the speed of convergence of the projected mean-square displacement of the underlying process which may serve as the theoretical foundation for the de…

65C05Statistics and Probability65N21stochastic homogenizationquantitative convergence result01 natural sciencesHomogenization (chemistry)78M40general reflecting diffusion process010104 statistics & probabilitysymbols.namesakeFeynman–Kac formula60J4535Q60Applied mathematicsFeynman diagramBoundary value problemSkorohod decomposition0101 mathematicsElectrical impedance tomographyBrownian motionMathematicsrandom conductivity field65N75010102 general mathematicsFeynman–Kac formulaLipschitz continuityBounded functionstochastic forward problemsymbols60J55Statistics Probability and Uncertainty60H30electrical impedance tomographyThe Annals of Applied Probability
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Optimal recovery of a radiating source with multiple frequencies along one line

2020

We study an inverse problem where an unknown radiating source is observed with collimated detectors along a single line and the medium has a known attenuation. The research is motivated by applications in SPECT and beam hardening. If measurements are carried out with frequencies ranging in an open set, we show that the source density is uniquely determined by these measurements up to averaging over levelsets of the integrated attenuation. This leads to a generalized Laplace transform. We also discuss some numerical approaches and demonstrate the results with several examples.

attenuated Radon transformMultispectralRAYUniqueness theorem01 natural sciencesinversio-ongelmat44A10 (Primary) 65R32 44A60 46N40 65Z05 (Secondary)030218 nuclear medicine & medical imaging0302 clinical medicine111 MathematicsDiscrete Mathematics and CombinatoricstietokonetomografiaPharmacology (medical)INVERSIONnuclear medicineBeam hardeningPhysicsLaplace transformDetectorNumerical Analysis (math.NA)Inverse problemuniqueness theoremFunctional Analysis (math.FA)Mathematics - Functional AnalysisMultiplicative system theoremkuvantaminensovellettu matematiikkaModeling and SimulationSPECTLine (geometry)numeerinen analyysipositroniemissiotomografiaemission computed tomographyAttenuated Radon transformEmission computed tomographyControl and OptimizationLaplace transformmultispectralOpen setCollimated light03 medical and health sciencesnuclear medicine.multiplicative system theoremFOS: Mathematicsinverse source problemMathematics - Numerical Analysis0101 mathematicsAttenuation010102 general mathematicsInverse source problemRangingComputational physicsTENSOR TOMOGRAPHYPETbeam hardeningNuclear MedicineAnalysis
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Probabilistic interpretation of the Calderón problem

2017

In this paper, we use the theory of symmetric Dirichlet forms to give a probabilistic interpretation of Calderon's inverse conductivity problem in terms of reflecting diffusion processes and their corresponding boundary trace processes. This probabilistic interpretation comes in three equivalent formulations which open up novel perspectives on the classical question of unique determinability of conductivities from boundary data. We aim to make this work accessible to both readers with a background in stochastic process theory as well as researchers working on deterministic methods in inverse problems.

Control and OptimizationStochastic processComputer science010102 general mathematicsProbabilistic logicBoundary (topology)Inverse problem01 natural sciencesDirichlet distributionInterpretation (model theory)010104 statistics & probabilitysymbols.namesakeModeling and SimulationNeumann boundary conditionsymbolsDiscrete Mathematics and CombinatoricsApplied mathematics0101 mathematicsAnalysisTRACE (psycholinguistics)Inverse Problems & Imaging
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