Filters








51 Hits in 10.2 sec

Stochastic Galerkin finite element method with local conductivity basis for electrical impedance tomography [article]

Nuutti Hyvönen, Matti Leinonen
2015 arXiv   pre-print
framework of the complete electrode model.  ...  The uncertainty in the pixel values is propagated to the electrode measurements by numerically solving the forward problem of impedance tomography by a stochastic Galerkin finite element method in the  ...  We would like to thank Professor Jari Kaipio's research group at the University of Eastern Finland (Kuopio) for granting us access to their EIT devices.  ... 
arXiv:1412.1941v2 fatcat:eo5y3p7oezcofjbp5k47feba64

Polynomial collocation for handling an inaccurately known measurement configuration in electrical impedance tomography [article]

Nuutti Hyvönen, Vesa Kaarnioja, Lauri Mustonen, Stratos Staboulis
2016 arXiv   pre-print
The objective of electrical impedance tomography is to reconstruct the internal conductivity of a physical body based on measurements of current and potential at a finite number of electrodes attached  ...  In this work, the dependence of the electrode measurements on all aforementioned model properties is parametrized via polynomial collocation.  ...  We would like to thank Professor Jari Kaipio's research group at the University of Eastern Finland (Kuopio) for granting us access to their EIT devices.  ... 
arXiv:1604.00353v2 fatcat:mazndmss6rajbnnuzissncul5q

Polynomial Collocation for Handling an Inaccurately Known Measurement Configuration in Electrical Impedance Tomography

N. Hyvönen, V. Kaarnioja, L. Mustonen, S. Staboulis
2017 SIAM Journal on Applied Mathematics  
The objective of electrical impedance tomography is to reconstruct the internal conductivity of a physical body based on measurements of current and potential at a finite number of electrodes attached  ...  Although the conductivity is the quantity of main interest in impedance tomography, a real-world measurement configuration includes other unknown parameters as well: The information on the contact resistances  ...  We would like to thank Professor Jari Kaipio's research group at the University of Eastern Finland (Kuopio) for granting us access to their EIT devices.  ... 
doi:10.1137/16m1068888 fatcat:b2esfxeucvhrponvw6sqlfm43a

Detecting stochastic inclusions in electrical impedance tomography

Andrea Barth, Bastian Harrach, Nuutti Hyvönen, Lauri Mustonen
2017 Inverse Problems  
This work considers the inclusion detection problem of electrical impedance tomography with stochastic conductivities.  ...  It is shown that a conductivity anomaly with a random conductivity can be identified by applying the Factorization Method or the Monotonicity Method to the mean value of the corresponding Neumann-to-Dirichlet  ...  Electrical impedance tomography (EIT) is an imaging modality for finding information about the internal conductivity of an examined physical body from boundary measurements of current and potential.  ... 
doi:10.1088/1361-6420/aa8f5c fatcat:75cxaiq3zne2xja5kxqc5uhdge

Generalized linearization techniques in electrical impedance tomography

Nuutti Hyvönen, Lauri Mustonen
2018 Numerische Mathematik  
The method is directly applicable to discrete settings, including the complete electrode model. We also consider Fréchet derivatives of the logarithmic operators.  ...  Electrical impedance tomography aims at reconstructing the interior electrical conductivity from surface measurements of currents and voltages.  ...  Acknowledgments This work was supported by the Academy of Finland (decision 267789) and the Finnish Foundation for Technology Promotion TES.  ... 
doi:10.1007/s00211-018-0959-1 fatcat:4xgb4ul4kjb6xbbvtvpqdvyeda

Generalized linearization techniques in electrical impedance tomography [article]

Nuutti Hyvönen, Lauri Mustonen
2017 arXiv   pre-print
The method is directly applicable to discrete settings, including the complete electrode model. We also consider Fr\'echet derivatives of the logarithmic operators.  ...  Electrical impedance tomography aims at reconstructing the interior electrical conductivity from surface measurements of currents and voltages.  ...  Acknowledgments This work was supported by the Academy of Finland (decision 267789) and the Finnish Foundation for Technology Promotion TES.  ... 
arXiv:1705.10559v1 fatcat:qlsbubkcbvdshk2lv3jcmf7wum

Relaxed Gauss-Newton methods with applications to electrical impedance tomography [article]

Jyrki Jauhiainen, Petri Kuusela, Aku Seppänen, Tuomo Valkonen
2020 arXiv   pre-print
We extensively evaluate the performance of the method on electrical impedance tomography (EIT).  ...  We prove that the method converges to a set of disjoint critical points given that the linearisation of the forward operator for the inverse problem is sufficiently precise.  ...  In the next section, we discuss speci c choices of these functions in the case of electrical impedance tomography.  ... 
arXiv:2002.08044v4 fatcat:q43nzrxidnejbf3gxr3lhmgm6u

Improved EEG source analysis using low-resolution conductivity estimation in a four-compartment finite element head model

Seok Lew, Carsten H. Wolters, Alfred Anwander, Scott Makeig, Rob S. MacLeod
2009 Human Brain Mapping  
We have also demonstrated the feasibility and applicability of the new method to simultaneously estimate brain and skull conductivity and a somatosensory source from measured tactile somatosensory-evoked  ...  As input data, the method needs T1-and PD-weighted magnetic resonance images for an improved modeling of the skull and the cerebrospinal fluid compartment and evoked potential data with high signal-to-noise  ...  ACKNOWLEDGMENTS The authors thank the anonymous reviewers for their helpful critics and comments that significantly improved our manuscript.  ... 
doi:10.1002/hbm.20714 pmid:19117275 pmcid:PMC2733918 fatcat:jnm6csqjt5aa7nfxovre4o4eum

Conditionally Gaussian Hypermodels for Cerebral Source Localization [article]

Daniela Calvetti, Harri Hakula, Sampsa Pursiainen, Erkki Somersalo
2008 arXiv   pre-print
Bayesian modeling and analysis of the MEG and EEG modalities provide a flexible framework for introducing prior information complementary to the measured data.  ...  This prior information is often qualitative in nature, making the translation of the available information into a computational model a challenging task.  ...  Appendix: Complete electrode model and FEM for EEG/MEG This appendix describes briefly how the electric and magnetic lead field matrices can be constructed through the complete electrode model [28] and  ... 
arXiv:0811.3185v1 fatcat:d5wkdzgirrf6jeqcpe5qwh74xi

Probabilistic Numerical Methods for Partial Differential Equations and Bayesian Inverse Problems [article]

Jon Cockayne, Chris Oates, Tim Sullivan, Mark Girolami
2017 arXiv   pre-print
This paper develops a probabilistic numerical method for solution of partial differential equations (PDEs) and studies application of that method to PDE-constrained inverse problems.  ...  In particular, the approach confers robustness to failure of the numerical PDE solver, with statistical inferences driven to be more conservative in the presence of substantial discretisation error.  ...  In addition they are grateful to the developers of the Python libraries Autograd and GPyOpt.  ... 
arXiv:1605.07811v3 fatcat:w4e34dlajrelde3b2y7lrihcdm

Boosting Rechargeable Batteries R&D by Multiscale Modeling: Myth or Reality?

Alejandro A. Franco, Alexis Rucci, Daniel Brandell, Christine Frayret, Miran Gaberscek, Piotr Jankowski, Patrik Johansson
2019 Chemical Reviews  
The outcome is compared both to results of other modeling strategies as well as to the vast pool of experimental data available.  ...  This review addresses concepts, approaches, tools, and outcomes of multiscale modeling used to design and optimize the current and next generation rechargeable battery cells.  ...  funding support of the postdoctoral position of A.R. through the project POROUS4APP (Grant 686163).  ... 
doi:10.1021/acs.chemrev.8b00239 pmid:30859816 pmcid:PMC6460402 fatcat:l2iubx435zb7ddpmabujgg5r2u

A design methodology for 2D sparse NDE arrays using an efficient implementation of refracted-ray TFM

Jerzy Dziewierz, Timothy Lardner, Anthony Gachagan
2013 2013 IEEE International Ultrasonics Symposium (IUS)  
A second technology uses ultrasound to noninvasively control the microstructure of collagen within engineered tissues.  ...  The development of more complex tissues has been limited by the need for techniques that can rapidly organize cells and proteins within large three-dimensional scaffolds, and the need to create vascular  ...  The authors acknowledge the ANR and DGA for their support under the project Metactif, grant ANR-11-ASTR-015.  ... 
doi:10.1109/ultsym.2013.0035 fatcat:th5znfh7y5bklfdbmhb4u6iq2i

Certifying Unstability of Switched Systems Using Sum of Squares Programming

Benoît Legat, Pablo Parrilo, Raphaël Jungers
2020 SIAM Journal of Control and Optimization  
Acknowledgements We argue that, from a modeling point of view, the assumptions of distinct timescales is ubiquitous when modeling complex systems.  ...  We, however, explore the stability properties of the slow-fast mechanical system via the passivity properties of Σ 1 and Σ 2 together with the interconnection which leads to (3).  ...  For this reason, the completion of the FEM model using system identification techniques will be pursued.  ... 
doi:10.1137/18m1173460 fatcat:ytlzbwk7vbampbuyo6snenz33m

The structural acoustic properties of stiffened shells

Yu Luan
2008 Journal of the Acoustical Society of America  
Promising approaches to interpreting effects include avoidance of habitat, energetics of foraging, and applying models of anti-predator behavior to human disturbance.  ...  Typical illustrations of the CAA approach will then be presented and applications for transportation systems will be discussed. 1a MON. AM 2969 2969 Invited Papers 1:00 1pAAa1.  ...  transducer has been developped to get the mechanical impedance of the sample from the measurement of the electrical impedance, 3. mechanical properties of the frame are derived by inverse method using  ... 
doi:10.1121/1.2932806 fatcat:zohbewf2k5h7fly2hoqzfdk42e

Trends in preference, programming and design of concert halls for symphonic music

Anders C. Gade
2008 Journal of the Acoustical Society of America  
transducer has been developped to get the mechanical impedance of the sample from the measurement of the electrical impedance, 3. mechanical properties of the frame are derived by inverse method using  ...  In cochlear implants, simultaneous stimulation of adjacent electrodes, can be used to shape the electric fields generated within the cochlea.  ...  Before going to such applications, a detailed parametric study is needed to investigate the sensitivity of the interactions measurement to various parameters ͑range, geoacoustic structure,...͒.  ... 
doi:10.1121/1.2932471 fatcat:hhka5ml2fvcszklkzau2lw3gka
« Previous Showing results 1 — 15 out of 51 results